ST. LOUIS COUNTY
DEPARTMENT OF TRANSPORTATION
CONSTRUCTION DIVISION
RESIDENT ENGINEERS’
MANUAL
1
Original Date: 1/3/94
Revised Date: 05/27/16
TABLE OF CONTENTS
TABLE OF CONTENTS .............................................................................................................................2
TABLE OF ILLUSTRATIONS & TABLES ...........................................................................................13
TABLE OF FORMULAS...........................................................................................................................14
SECTION 100 – PRE-CONSTRUCTION PHASE .................................................................................15
101 GENERAL .......................................................................................................................................15
102 CONSTRUCTION CONTRACT AND SPECIFICATIONS ......................................................15
103 CONSTRUCTION PLANS ............................................................................................................16
103.1 TITLE SHEET ........................................................................................................... 16
103.2 “A” AND “B” SHEETS ............................................................................................... 17
103.3 STANDARD DRAWINGS ......................................................................................... 18
103.4 DETOURS ................................................................................................................ 18
103.5 CROSS SECTIONS .................................................................................................. 19
104 FIELD CHECK ...............................................................................................................................19
105 DIGITAL RECORD OF PRE EXISTING JOB SITE ................................................................20
106 UTILITY RELOCATION ............................................................................................................21
107 CONSTRUCTION STAKING ......................................................................................................22
107.1 MATERIALS FURNISHED BY CONTRACTOR ........................................................ 22
107.2 PRECONSTRUCTION LAYOUT .............................................................................. 22
107.3 CLEARING LIMITS ................................................................................................... 23
107.4 SITE BENCH MARKS ............................................................................................... 23
107.5 PROPERTY CORNERS AND MONUMENTATION .................................................. 23
107.6 USGS, MSD AND OTHER BENCH MARKS ............................................................ 24
108 FIELD MEETING PRIOR TO PRECONSTRUCTION CONFERENCE ...............................24
109 PRECONSTRUCTION CONFERENCE .....................................................................................24
109.1 SPEACIAL ITEMS .................................................................................................... 31
110 RELATED PROJECT CORRESPONDENCE ...........................................................................32
110.1 TEMPORARY EROSION AND SEDIMENT CONTROL ........................................... 32
110.2 SUBCONTRACTOR APPROVAL REQUEST ........................................................... 32
110.3 MATERIAL SUPPLIER APPROVAL REQUEST ....................................................... 33
110.4 SUPERINTENDENT ................................................................................................. 34
110.5 BAR CHART FOR CONSTRUCTION SCHEDULE .................................................. 34
110.6 EQUAL EMPLOYMENT OPPORTUNITY ................................................................. 34
110.7 NON-DISCRIMINATION ........................................................................................... 35
2
Original Date: 1/3/94
Revised Date: 05/27/16
111 NOTICE TO PROCEED ...............................................................................................................35
112 NOTICE TO PROPERTY OWNERS ..........................................................................................35
113 WASTE DISPOSAL SITES AND BORROW AREAS ...............................................................36
SECTION 200 – EARTHWORK AND EXCAVATION ........................................................................37
201 CONSTRUCTION STAKING ......................................................................................................37
201.1 MATERIALS FURNISHED BY CONTRACTOR ........................................................ 37
202 CONSTRUCTION LAYOUT ........................................................................................................38
202.1 CLEARING LIMITS ................................................................................................... 38
202.2 BENCH MARKS........................................................................................................ 38
202.3 SLOPE STAKES ....................................................................................................... 39
202.4 CROSS SECTIONS .................................................................................................. 40
202.5 ROCK SECTIONS .................................................................................................... 41
203 DETERMINING QUANTITY ......................................................................................................41
204 WASTE DISPOSAL SITES AND BORROW AREAS ...............................................................41
205 MISCELLANEOUS ITEMS..........................................................................................................42
206 SUBGRADE ....................................................................................................................................42
206.1 DIRT SUBGRADE (CONCRETE) ............................................................................. 42
206.2 DIRT SUBGRADE (ASPHALT) ................................................................................. 44
207 EXCAVATION FOR BRIDGES ...................................................................................................45
207.1 CLASS 1 EXCAVATION ........................................................................................... 45
207.2 CLASS 2 EXCAVATION ........................................................................................... 45
207.3 INSPECTION OF EXCAVATIONS............................................................................ 46
208 EXCAVATION FOR BOX CULVERT .......................................................................................47
SECTION 300 – AGGREGATE BASES ..................................................................................................48
301 CONSTRUCTION STAKING ......................................................................................................48
302 SUBGRADE PLANER ...................................................................................................................49
303 AGGREGATE SUBGRADE .........................................................................................................49
304 FORM PAVING..............................................................................................................................50
305 FIELD MEASURMENT ................................................................................................................50
306 CHECK LIST – AGGREGATE BASE ........................................................................................51
SECTION 400 – FLEXIBLE PAVEMENT .............................................................................................53
401 GENERAL .......................................................................................................................................53
402 CONSTRUCTION LAYOUT ........................................................................................................53
402.1 SUBGRADE PREPARATION (OVERLAY) ............................................................... 54
3
Original Date: 1/3/94
Revised Date: 05/27/16
403 PAVING FABRICS ........................................................................................................................54
403.1 SURFACE PREPARATION ...................................................................................... 54
403.2 FABRIC PLACEMENT .............................................................................................. 55
404 EQUIPMENT ..................................................................................................................................55
404.1 DISTRIBUTOR SYSTEMS ....................................................................................... 55
404.2 HAULING EQUIPMENT ............................................................................................ 57
404.3 ROLLERS ................................................................................................................. 57
404.4 BOX SPREADER...................................................................................................... 58
404.5 ASPHALT PAVER .................................................................................................... 59
404.6 AUTOMATIC SCREED CONTROL .......................................................................... 60
405 MATERIALS ..................................................................................................................................61
405.1 PRIME AND TACK COATS ...................................................................................... 61
405.2 ASPHALT ................................................................................................................. 62
406 ON-SITE INSPECTION PROCEDURES (ASSOCIATED ITEMS) ........................................63
406.1 PERSONNEL ............................................................................................................ 63
406.2 TEMPERATURE RESTRICTIONS ........................................................................... 63
406.3 MATERIAL SUPPLIERS (24-HOUR NOTICE) ......................................................... 64
406.4 TEMPORARY STRIPING ......................................................................................... 64
406.5 LOOP DETECTORS ................................................................................................. 64
406.6 UTILITY ADJUSTMENTS ......................................................................................... 65
406.7 MANHOLE ADJUSTMENT RINGS ........................................................................... 66
406.8 DRIVEWAYS AND STREET INTERSECTIONS ....................................................... 67
406.9 SIGNING ................................................................................................................... 68
406.10 MISCELLANEOUS ................................................................................................. 69
407 TACK AND PRIME APPLICATION ..........................................................................................71
408 PAVING OPERATION .................................................................................................................73
408.1 UTILIZING THE VARIOUS SCREED CONTROLS ................................................... 73
408.2 WEDGE COURSE .................................................................................................... 74
408.3 MAIN LINE CONSTRUCTION PROCEDURES ........................................................ 75
408.4 BUTT JOINTS ........................................................................................................... 76
408.5 TRANSITIONAL JOINTS .......................................................................................... 76
408.6 CONSTRUCTION JOINTS ....................................................................................... 76
408.7 LONGITUDINAL JOINTS .......................................................................................... 77
408.8 COMPACTION REQUIREMENTS ............................................................................ 77
4
Original Date: 1/3/94
Revised Date: 05/27/16
408.9 ROLLING .................................................................................................................. 77
409 SEAL COAT....................................................................................................................................79
409.1 AGGREGATE SPREADER ...................................................................................... 79
410 PAVEMENT SURFACER .............................................................................................................80
411 TESTING .........................................................................................................................................82
412 CHECK LIST – FLEXIBLE PAVEMENT..................................................................................83
SECTION 500 – RIGID PAVEMENT ......................................................................................................86
501 CONSTRUCTION STAKING ......................................................................................................86
502 SLIP FORM PAVING ....................................................................................................................87
503 FORMS ............................................................................................................................................88
504 PAVING ACCESSORIES..............................................................................................................89
504.1 KEYWAY .................................................................................................................. 90
504.2 BENT BARS ............................................................................................................. 90
504.3 CONTRACTION JOINTS .......................................................................................... 90
504.4 EXPANSION JOINTS ............................................................................................... 91
504.5 CONSTRUCTION JOINTS ....................................................................................... 91
504.6 OTHER APPURTENANCES .................................................................................... 91
504.7 DOWEL BARS FOR CURB ...................................................................................... 92
505 JOINT DETAILS ............................................................................................................................92
506 CONCRETE PAVING EQUIPMENT .........................................................................................92
506.1 VIBRATORY SCREED ............................................................................................. 93
506.2 RAIL FINISHING MACHINE ..................................................................................... 94
506.3 SUBGRADE PLANER .............................................................................................. 96
506.4 CONCRETE SPREADER ......................................................................................... 96
506.5 SLIP FORM PAVINIG EQUIPMENT ......................................................................... 96
507 CONCRETE DELIVERY ..............................................................................................................98
507.1 NON-AGITATING TRUCKS ...................................................................................... 98
507.2 TRUCK MIXED ......................................................................................................... 98
507.3 AGITATING TRUCKS ............................................................................................... 99
507.4 MATERIAL ................................................................................................................ 99
508 PAVING OPERATION ...............................................................................................................100
508.1 PERSONNEL .......................................................................................................... 100
509 PAVING PROCEDURES ............................................................................................................101
509.1 PAVEMENT DEPTH CHECK ................................................................................. 101
5
Original Date: 1/3/94
Revised Date: 05/27/16
509.2 BEGINNING THE POUR ........................................................................................ 102
509.3 DURING THE POUR .............................................................................................. 102
509.4 INTERRUPTION OF THE POUR............................................................................ 103
509.5 SURFACE TEXTURE ............................................................................................. 103
510 CURING METHODS ...................................................................................................................104
511 SAWING AND SEALING JOINTS ............................................................................................105
512 OPENING TO TRAFFIC ............................................................................................................106
513 COLD WEATHER CONCRETE ...............................................................................................107
513.1 TEMPERATURE ..................................................................................................... 107
514 CONCRETE REPLACEMENT (MAINTENANCE) CONTRACTS .....................................108
514.1 PRELIMINARY WORK PRIOR TO AWARD OF CONTRACT ................................ 108
514.2 PRE-CONSTRUCTION CONFERENCE ................................................................ 109
514.3 CONSTRUCTION PROCEDURES ......................................................................... 109
514.4 CLOSURE OF PAVEMENT SLABS ....................................................................... 110
514.5 SIGNS, BARRICADES AND FLAGGER ................................................................. 111
514.6 INSPECTORS’ WORKSHEETS ............................................................................. 111
514.7 BACKFILL ............................................................................................................... 111
514.8 JOINT SEALING MATERIAL .................................................................................. 111
514.9 RESIDENT ENGINEER’S DUTIES ......................................................................... 111
515 CHECK LIST – RIGID PAVEMENT ........................................................................................112
SECTION 600 – DRAINAGE CONSTRUCTION ................................................................................115
601 GENERAL .....................................................................................................................................115
601.1 RIGHT-OF-WAY EASEMENTS .............................................................................. 115
602 CONSTRUCTION STAKING ....................................................................................................115
602.1 LASER METHOD .....................................................................................................................116
602.2 STRUCTURES ....................................................................................................... 117
603 MATERIALS ................................................................................................................................119
603.1 PIPE........................................................................................................................ 119
603.2 JOINT SEALING (WITH MSD APPROVAL) ........................................................... 120
603.3 GASKET JOINTS (MSD TYPE A THRU D) .......................................................... 120
604 EXCAVATION .............................................................................................................................120
604.1 EXISTING UTILITIES ............................................................................................. 121
604.2 BRACING AND SHORING ..................................................................................... 121
604.3 ROCK CUT ............................................................................................................. 121
6
Original Date: 1/3/94
Revised Date: 05/27/16
604.4 UNSTABLE AREAS ................................................................................................ 122
604.5 TRENCH WIDTH .................................................................................................... 122
604.6 TRENCH LENGTH ................................................................................................. 122
604.7 INSPECTION OF EXCAVATION ............................................................................ 122
605 PIPE BEDDING ............................................................................................................................123
606 EXCESSIVE GRADES ................................................................................................................124
606.1 CONCRETE CRADLE ............................................................................................ 124
606.2 BEDDING FOR EXCESSIVE GRADE (CAP) ......................................................... 125
607 PIPE PLACEMENT .....................................................................................................................125
607.1 UTILITY CONFLICT DURING SEWER INSTALLATION ........................................ 126
607.2 CONCRETE ENCASEMENT .................................................................................. 127
607.3 HEADWALLS AND TOE WALLS ............................................................................ 128
607.4 PIPE COLLARS ...................................................................................................... 128
607.5 INSPECTION OF PIPE LAYING ............................................................................. 128
608 BACKFILL ....................................................................................................................................129
608.1 GRANULAR BACKFILL .......................................................................................... 129
609 BORING ........................................................................................................................................130
610 GROUTING ..................................................................................................................................131
611 FIELD MEASUREMENT ...........................................................................................................131
612 STRUCTURES..............................................................................................................................131
612.1 VERTICAL ALIGNMENT OF STRUCTURES ......................................................... 131
612.2 CONCRETE BASES ............................................................................................... 131
612.3 BRICK ..................................................................................................................... 132
612.4 STEPS .................................................................................................................... 132
612.5 TRANSITIONS ........................................................................................................ 133
612.6 INVERTS ................................................................................................................ 133
612.7 INSIDE DROP STRUCTURES ............................................................................... 134
612.8 REINFORCED STRUCTURES AND DROP STRUCTURES ................................. 134
612.9 INSPECTION OF STRUCTURES........................................................................... 134
612.10 TUCKPOINTING AND PLASTERING EXISTING DRAINAGE STRUCTURES .... 136
613 MANHOLE FRAMES AND COVERS......................................................................... 136
614 INLETS ..........................................................................................................................................136
614.1 INLET COVERS...................................................................................................... 136
614.2 GRATED INLETS ................................................................................................... 137
7
Original Date: 1/3/94
Revised Date: 05/27/16
614.3 SIDE INTAKE UNITS .............................................................................................. 137
614.4 STREET INLETS .................................................................................................... 137
614.5 INSPECTION OF INLETS ...................................................................................... 138
615 PRECAST AND CAST-IN-PLACE CONCRETE STRUCTURES ........................................138
615.1 INSPECTION OF CAST-IN-PLACE CONCRETE STRUCTURES ......................... 139
616 PRECAST CONCRETE BOX CULVERTS ..............................................................................139
617 STRUCTURES BUILT ON MoDOT RIGHT-OF-WAY .........................................................139
618 EXISTING STRUCTURES .........................................................................................................140
619 FIELD MEASUREMENTS .........................................................................................................140
619.1 BASIS OF PAYMENT ............................................................................................. 140
620 GABION WALL INSULATION .................................................................................................141
620.1 CONSTRUCTION STAKING .................................................................................. 141
620.2 MATERIALS ........................................................................................................... 141
620.3 CONSTRUCTION REQUIREMENTS ..................................................................... 142
620.4 BASIS OF PAYMENT ............................................................................................. 143
621 SINKHOLE AREAS.....................................................................................................................143
SECTION 700 - STRUCTURES .............................................................................................................145
701
GENERAL ..................................................................................................................................145
702
SURVEY LAYOUT PRINCIPLES ..........................................................................................145
702.1 BRIDGES .............................................................................................................. 145
702.2 BOX CULVERTS................................................................................................... 147
702.3 RETAINING WALLS ............................................................................................... 148
702.4
703
704
HAUNCHING ..................................................................................................... 148
SHEET PILING...................................................................................................... 148
FOUNDATIONS .....................................................................................................................149
704.1 POURED IN PLACE FOUNDATION ..................................................................... 149
704.2
705
PEDESTAL PILING............................................................................................ 150
BEARING PILE .........................................................................................................................152
705.1 PILING MATERIAL................................................................................................ 152
705.2 PILING DRIVING EQUIPMENT ............................................................................ 152
705.3 PILE DRIVING PROCEDURE REVIEW ................................................................ 154
705.4 SPLICES ............................................................................................................... 157
705.5 FALSEWORK PILING ........................................................................................... 158
705.6
PILE PAYMENT ................................................................................................. 158
8
Original Date: 1/3/94
Revised Date: 05/27/16
706
SUBSTRUCTURAL UNITS .....................................................................................................158
706.1
FORMS .............................................................................................................. 159
706.2
COLUMNS ......................................................................................................... 159
706.3
INSPECTION OF FOOTINGS AND COLUMNS ................................................ 159
706.4
ABUTMENTS AND CAPS .................................................................................. 160
706.5
FORMING .......................................................................................................... 160
706.6
BOX-OUTS ........................................................................................................ 161
706.7
WEEP HOLES ................................................................................................... 162
707
707.1
708
REINFORCING STEEL ......................................................................................... 162
INSPECTION ..................................................................................................... 166
PLACING SUBSTRUCTURE CONCRETE ..........................................................................168
708.1
TEMPERATURE RESTRICTIONS .................................................................... 168
708.2 FORMS AND CONCRETE .................................................................................... 169
708.3 PUMPING ............................................................................................................. 170
708.4 FORM REMOVAL ................................................................................................. 172
709
TYPES OF STRUCTURES ......................................................................................................172
709.1 STRUCTURAL STEEL GIRDERS......................................................................... 173
709.2 PRESTRESSED CONCRETE I-GIRDERS ........................................................... 174
709.3 PRECAST BOX GIRDERS/BOX BEAMS ............................................................. 175
710
DECK FORMING ..................................................................................................................176
710.1 HAUNCH ............................................................................................................... 176
710.2 DECKING .............................................................................................................. 177
710.3 REINFORCING STEEL ......................................................................................... 178
710.5 BRIDGE CONDUIT SYSTEMS ............................................................................. 179
711
DECK POUR ..............................................................................................................................180
711.2
FINISHING MACHINE ....................................................................................... 180
711.3 CONCRETE FINISHING ....................................................................................... 181
711.4
CONCRETE PLACEMENT ................................................................................ 182
711.5
IRREGULAR DECK AREAS .............................................................................. 183
711.6
CURING ............................................................................................................. 184
711.1 WEATHER CONDITIONS ..................................................................................... 184
711.7
712
STRAIGHTEDGED ............................................................................................ 185
BARRIER WALL, SIDEWALK AND PARAPET WALLS .............................................185
712.1 RUBBING .............................................................................................................. 187
9
Original Date: 1/3/94
Revised Date: 05/27/16
712.2 PLAQUE ................................................................................................................ 187
713
SEALING ....................................................................................................................................187
714
DAMPPROOFING ....................................................................................................................188
715
BACKFILLING .........................................................................................................................188
716
APPROACH SLAB ....................................................................................................................188
716.1 MUDJACKING HOLES ......................................................................................... 189
716.2 BARRIER WALL TRANSITION SECTION ............................................................ 189
717
PEDESTRIAN FENCE OR ALUMINUM HANDRAIL .......................................................190
718
WATERPROOFING .................................................................................................................193
719
TIMBER CONSTRUCTION ....................................................................................................193
719.1 TIMBER RETAINING WALLS ............................................................................... 194
720
CRIB RETAINING WALLS ....................................................................................................195
721
STRUCTURAL PLATE BRIDGE AND CULVERT CONSTRUCTION ...........................196
721.1 STRUCTURAL PLATE PIPE AND PIPE ARCH CULVERT .................................. 196
721.2 STRUCTURALLY REINFORCED PLATE ARCH AND PIPE ARCH ..................... 197
721.3 PIPE ARCHES ...................................................................................................... 198
722
PAINTING ..................................................................................................................................198
723
CHECK LIST – DECK POURS ...............................................................................................202
SECTION 800 – ROADSIDE DEVELOPMENT ..................................................................................207
801 PLANTING TREES, SHRUBS AND OTHER PLANTS .........................................................207
801.1 GENERAL ............................................................................................................... 207
802 PLANTING REQUIREMENTS .................................................................................................207
803 TREE STAKING ..........................................................................................................................207
804 INSPECTION REQUIRED .........................................................................................................208
805 METHOD OF PAYMENT...........................................................................................................208
SECTION 900 – TRAFFIC SIGNALS & TRAFFIC CONTROL .......................................................209
901 TRAFFIC SIGNALS IDENTIFICATION CODE ....................................................................209
902 COORDINATION ........................................................................................................................209
903 CONSTRUCTION REQUIREMENTS ......................................................................................210
903.1 CONDUIT ............................................................................................................... 210
903.2 SIGNALS ................................................................................................................ 211
903.3 CABLES .................................................................................................................. 212
904 SIGNAL OPERATION ................................................................................................................214
905 METHOD OF MEASUREMENT ...............................................................................................214
10
Original Date: 1/3/94
Revised Date: 05/27/16
906 TRAFFIC CONTROL..................................................................................................................215
906.1 GENERAL ............................................................................................................... 216
906.2 RESPONSIBILITY .................................................................................................. 216
906.3 FUNDAMENTAL PRINCIPLES AND PROCEDURES ............................................ 217
907 SIGNS.............................................................................................................................................222
907.1 DESIGN .................................................................................................................. 222
907.2 ILLUMINATION / REFLECTORIZATION ................................................................ 222
907.3 POSITION OF SIGNS ............................................................................................. 224
907.4 ERECTION OF SIGNS ........................................................................................... 224
908 TYPES OF SIGNS ........................................................................................................................225
908.1 REGULATORY SIGNS ........................................................................................... 225
908.2 WARNING SIGNS .................................................................................................. 225
908.3 ADVANCE WARNING SIGNS ................................................................................ 226
908.4 MAINTENANCE AND MINOR CONSTRUCTION WARNINNG SIGNS .................. 227
908.5 WARNING SIGNS FOR BLASTING AREAS .......................................................... 227
908.6 GUIDE SIGNS ........................................................................................................ 228
909 CHANNELIZING DEVICES ......................................................................................................229
909.1 CONES ................................................................................................................... 230
909.2 VERTICAL PANELS ............................................................................................... 230
909.3 CHANNELIZERS .................................................................................................... 231
909.4 BARRICADES......................................................................................................... 232
909.5 PORTABLE BARRIERS ......................................................................................... 233
910 MARKINGS ..................................................................................................................................234
911 DELINEATORS ...........................................................................................................................234
912 LIGHTING DEVICES .................................................................................................................235
913 FLAGGING AND HAND SIGNAL PROCEDURES ...............................................................236
SECTION 1000 – MATERIALS TESTING ..........................................................................................237
1001 GENERAL ...................................................................................................................................237
1002 FIELD TESTING .......................................................................................................................237
1003 SOILS TESTING ........................................................................................................................238
1003.1 EQUIPMENT REQUIRED ..................................................................................... 238
1003.2 FIELD DENSITY TEST BY SAND CONE METHOD............................................. 240
1003.3 MOISTURE CONTENT DETERMINATION .......................................................... 242
1003.4 SIGNIFICANCE OF TESTS .................................................................................. 243
11
Original Date: 1/3/94
Revised Date: 05/27/16
1003.5 FREQUENCY OF TESTING ................................................................................. 244
1004 CONCRETE TESTING .............................................................................................................244
1004.1 EQUIPMENT REQUIRED ..................................................................................... 245
1004.2 SLUMP TEST ....................................................................................................... 245
1004.3 AIR CONTENT TEST ........................................................................................... 246
1004.4 COMPRESSION CYLINDER TEST ...................................................................... 248
1004.5 SIGNIFICANCE OF TESTS .................................................................................. 250
1004.6 FREQUENCY OF TESTING ................................................................................. 250
1005 COUNTY LABORATORY SOILS TESTING ........................................................................250
1005.1 ATTERBERG LIMITS ........................................................................................... 251
1005.2 MOISTURE-DENSITY RELATION (PROCTOR TEST) ........................................ 252
1005.3 FREQUENCY OF TESTING ................................................................................. 253
1006 COUNTY LABORATORY AGGREGATE TESTING ..........................................................253
1006.1 ATTERBERG LIMITS ........................................................................................... 253
1006.2 MOISTURE – DENSITY RELATION..................................................................... 254
1006.3 GRADATION TESTS ............................................................................................ 254
1006.4 FREQUENCY OF TESTING ................................................................................. 255
1007 COUNTY LABORATORY BITUMINOUS MATERIALS TESTING ................................255
1007.1 DENSITY DETERMINATIONS ............................................................................. 255
1007.2 FREQUENCY OF TEST ....................................................................................... 255
1008 COUNTY LABORATORY LIQUID ASPHALT TESTING .................................................256
1008.1 EMULSIFIED ASPHALTS ..................................................................................... 256
1008.2 FREQUENCY OF TESTING ................................................................................. 256
1009 PORTLAND CEMENT CONCRETE INSPECTION ............................................................256
1009.1 SAMPLING BY RESIDENT ENGINEER AND MATERIALS PERSONNEL .......... 257
1009.2 GRADATION CONTROL AND SIEVE ANALYSIS................................................ 257
1009.3 MOISTURE CONTROL OF AGGREGATE ........................................................... 257
1009.4 YIELD TESTS ....................................................................................................... 258
1009.5 FREQUENCY OF TESTING ................................................................................. 258
1010 INSPECTION OF DRAINAGE ITEMS ..................................................................................258
1010.1 BRICK TESTING .................................................................................................. 258
1010.2 FREQUENCY OF TESTING BRICK ..................................................................... 258
1010.3 TESTING OF A PIPE ............................................................................................ 259
1011 TESTING METAL PRODUCTS AND MISCELLANEOUS ITEMS ..................................259
12
Original Date: 1/3/94
Revised Date: 05/27/16
1011.1 SURFACE COATINGS ......................................................................................... 259
1012 REINFORCING STEEL ........................................................................................... 259
1013 PRESTRESSED CONCRETE BEAM INSPECTION............................................................260
1014 STRUCTURAL STEEL INSPECTION ...................................................................................260
1015 CERTIFICATION REQUIREMENTS ....................................................................................260
1016 RECORD TESTING ..................................................................................................................261
1017 SMALL QUANTITY ACCEPTANCE .....................................................................................262
TABLE OF ILLUSTRATIONS & TABLES
ILLUSTRATION 103.1 – SAMPLE TITLE SHEET..............................................................................17
ILLUSTRATION 103.2A – SAMPLE “A” SHEET ................................................................................17
ILLUSTRATION 103.2B – SAMPLE “B” SHEET.................................................................................18
ILLUSTRATION 103.5 – SAMPLE CROSS SECTION SHEET .........................................................19
ILLUSTRATION 202.3 – TYPICAL SLOPE STAKE INFORMATION ............................................40
ILLUSTRATION 501 – TYPICAL PAVEMENT & RADIUS STAKES .............................................87
ILLUSTRATION 602 – TYPICAL SEWER STAKING ......................................................................116
ILLUSTRATION 602.2A – TYPICAL INLET STAKING ..................................................................118
ILLUSTRATION 602.2B – TYPICAL FLARED END SECTION STAKING ..................................119
ILLUSTRATION 702.1 – TYPICAL BRIDGE STAKING PLAN ......................................................147
ILLUSTRATION 702.2 – TYPICAL BOX CULVERT STAKING PLAN ........................................147
ILLUSTRATION 702.3 – TYPICAL RETAINING WALLS STAKING PLAN ...............................148
TABLE 707 - DATA ON STANDARD DEFORMED BARS ...............................................................163
ILLUSTRATION 906.3A – TYPICAL ROAD CLOSURE PLAN ......................................................217
ILLUSTRATION 906.3B – WORKZONE COMPONENTS ...............................................................218
ILLUSTRATION 906.3C – DELINEATION & CHANNELIZATION ..............................................219
ILLUSTRATION 906.3D – EXAMPLE OF INAPPROPRIATE EXISTING PAVEMENT MARKINGS
.....................................................................................................................................................................220
ILLUSTRATION 906.3E – TYPICAL FLAGGING PROCEDURES ................................................220
ILLUSTRATION 906.3F – EXAMPLE OF FADED SHEETING & CHIPPED/PEELING
LETTERING .............................................................................................................................................221
ILLUSTRATION 906.3G – EXAMPLES OF IMPROPERLY INSTALLED AND/OR
MANIPULATED TRAFFIC CONTROL DEVICES............................................................................221
ILLUSTRATION 907.2A –REFLECTIVE SHEETING MATERIALS REFERENCE ...................223
ILLUSTRATION 907.2B – PROPER STORAGE OF WORKZONE SIGNAGE .............................223
ILLUSTRATION 907.3 – WORKZONE SIGNAGE POSITIONING ................................................224
13
Original Date: 1/3/94
Revised Date: 05/27/16
ILLUSTRATION 908.1 – EXAMPLES OF REGULATORY SIGNAGE ..........................................225
ILLUSTRATION 908.3 – EXAMPLES OF ADVANCED WARNING SIGNAGE...........................226
ILLUSTRATION 908.6A – EXAMPLE OF END CONSTRUCTION/END ROAD WORK SIGN 228
ILLUSTRATION 908.6B – EXAMPLE OF DETOUR SIGNAGE ON BARRICADE .....................229
ILLUSTRATION 909.1 – TRAFFIC CONE DIMENSIONS ...............................................................230
ILLUSTRATION 909.2 – VERTICAL CHANNELIZATION PANELS ............................................231
ILLUSTRATION 909.3 – EXAMPLES OF CHANNELIZER TYPES ..............................................231
ILLUSTRATION 909.4A – EXAMPLES OF TYPE I & II BARRICADES ......................................232
ILLUSTRATION 909.4B – EXAMPLE OF TYPE III BARRICADES ..............................................232
ILLUSTRATION 909.5 – EXAMPLES OF TYPE PORTABLE BARRIERS ...................................233
ILLUSTRATION 910 – EXAMPLES OF TEMPORARY PAVEMENT MARKINGS....................234
ILLUSTRATION 911 – EXAMPLES OF DELINEATORS ................................................................235
ILLUSTRATION 909.4A – FLAGGING & HAND SIGNAL PROCEDURES .................................236
ILLUSTRATION 1003.1A – NUCLEAR DENSITY GUAGE .............................................................239
ILLUSTRATION 1003.1B – SAND CONE DENSITY TEST ..............................................................239
TABLE 1005.2 – STANDARD RANGES FOR MOISTURE – DENSITY TEST (AASHTO T-99) 253
TABLE 1006.1 – STANDARD ATTERBERG LIMITS VALUES ......................................................254
TABLE 1006.2 – ANTICIPATED AGGREGATE BASE MOISTURE – DENSITY RESULTS .....254
TABLE 1017A – SMALL QUANTITY ACCEPTANCE .....................................................................262
TABLE 1017B – MINIMUM FIELD SCHEDULE FOR MATERIALS SAMPLING AND TESTING
.....................................................................................................................................................................264
TABLE 1017C – OFF-SYSTEMS GUIDE SCHEDULE FOR FEDERAL-AID ACCEPTANCE
SAMPLING AND TESTING ..................................................................................................................270
TABLE 1017D – COMMON CONSTRUCTION MATERIALS REQUIRING CERTIFICATIONS273
TABLE OF FORMULAS
FORMULA 305.0 – CALCULATING AGGREGATE APROX. TONNAGE .....................................51
FORMULA 405.1 – LIQUID ASPHALT CORRECTION FACTOR ...................................................62
FORMULA 407.0 – CALCULATING APROX. LIQUID ASPHALT QUANTITIES ........................72
FORMULA 408.3 – CALCULATING APROX. ASPHALT TONNAGE.............................................75
FORMULA 507.4 - CALCULATING APROX. CONCRETE VOLUME ..........................................100
14
Original Date: 1/3/94
Revised Date: 05/27/16
SECTION 100
PRE-CONSTRUCTION PHASE
101 GENERAL
Prior to the letting of a contract, a set of Construction Plans and the Construction Contract and Specifications
Book can be obtained from the Contracts Administrator at the Construction Division Office. These
Construction Plans and Specifications should be evaluated as soon as possible to determine any errors or
oversights. If any mistakes are found, they should be discussed with the Engineering Supervisor before the bid
opening date.
102 CONSTRUCTION CONTRACT AND SPECIFICATIONS
The Specifications contained in the contract book are referred to as the Special Provisions. The Special
Provisions contain requirements specific to the work which are not otherwise thoroughly detailed or set forth in
the “St. Louis County Standard Specifications for Highway Construction.” Whenever the Special Provisions
are in conflict with the Specifications or the plans, the Special Provisions will prevail.
The Special Provisions include, but are not limited to, the following information:
(a) The working or calendar days allotted to the project. It is important that the RE review the number of
days provided to complete the contract work and communicate concerns to the design engineer if
appropriate.
(b) The amount of liquidated damages charged for each calendar day or working day that all work remains
incomplete. If the contract has a completion date established then the liquidated dames will apply after
the contract end date has expired “and” pay item work still remains.
(c) Amount of insurance coverage required.
(d) ADA Checklist
(e) Workzone lane restrictions time limits. RE should communicate with Operations, Traffic
(f) Personnel to see if the hours listed in the contract can and/or should be adjusted.
(g) Items considered Specialty Items for the contract for subcontracting percent purposes.
(h) Contingent items.
(i) Hourly wage rates. The following link will take you to the MoDOT LPA quick links site:
http://epg.modot.org/index.php?title=136.14_Helpful_Information_and_Links#136.12.3_Helpful_Information_and_Links
When the bid documents of the Construction Contract are executed, the Contract becomes a legal document.
As a result, the Specifications and Special Provisions become a part of this legal document and are enforceable
as such.
The Design Division keeps an active data base of all Job Special Provisions that could appear in a contract,
below is a link to that database – contact Joe Kulessa, 314-615-58584 (or the current Engineering Supervisor) if
changes are needed to the verbiage:
15
Original Date: 1/3/94
Revised Date: 05/27/16
http://countynet.stlouisco.net/Departments/HwysPubWorks/HwyDesign/JSP/Forms/AllItems.aspx
The following information is contained in the contract:
(a) The estimated quantities and the contract unit price bid for each item. These unit costs will be used to
pay the contractor for the work performed under the contract.
(b) The Contract Bid Bond.
(c) The Certificate of Insurance.
(d) On the Job Training (OJT) Goal, if required by MoDOT on Federally funded jobs.
(e) Contract DBE Goal, expressed as a percentage of the total contract, as well as list of the Disadvantaged
Business Enterprises (DBE) employed by the Prime Contractor and a summation of their work
expressed in dollars to show the contract goals are met.
Example: If the total contract value is $1,000,000.00 and the DBE goal is 10% then the contract
should include a list of DBE subcontractors who will perform work on this contract and a
summation of their total expected value of work to meet or exceed:
$1,000,000.00 x 10% => $1000,000.00 in DBE subcontracted work.
103 CONSTRUCTION PLANS
103.1 TITLE SHEET
The Title Sheet contains the following:
(a) Name of the project,
(b) The county project number,
(c) The federal project number, if applicable
(d) Index of Sheets
(e) Date of Approval
(f) Project Limits
(g) Project Location
(h) Average Daily Traffic (ADT)
(i) Legend of Symbols
16
Original Date: 1/3/94
Revised Date: 05/27/16
ILLUSTRATION 103.1 – SAMPLE TITLE SHEET
103.2 “A” AND “B” SHEETS
“A” Sheets are a summary of all quantities identified on each page of the Construction Plans. These quantities
should be checked for accuracy in computation and compilation.
ILLUSTRATION 103.2A – SAMPLE “A” SHEET
17
Original Date: 1/3/94
Revised Date: 05/27/16
“B” Sheets quantities reflect items of construction for a particular page of the Construction Plans. As part of the
“B” Sheet, all storm and/or sanitary sewer data are shown in tabular form. Within this table, all information
concerning the phase of construction depicted on this plan sheet can be found.
ILLUSTRATION 103.2B – SAMPLE “B” SHEET
103.3 STANDARD DRAWINGS
Standard Drawings are included in the Construction Plans. These sheets should be checked for conformity with
the current standard shown in the “Design Criteria for the Preparation of Improvement Plans” These sheets
should also be checked for compliance with other adopted standards (i.e. Missouri Department of
Transportation (MoDOT), if work is being performed in State Right-of-Way).
Below is link to the current and approved Standard Drawings:
http://www.stlouisco.com/PropertyandRoads/HighwayPublicationsManuals/StandardDrawings
103.4 DETOURS
If detours are a part of the traffic handling on the project, care should be taken to follow the routing of the
detours in relation to the construction of the items called for in the plans. Make sure adequate width of
roadway, drainage, length of tapers, overhead clearance, detour construction quantities, detour signing and
correlation of construction items all check. Special attention should be paid to existing utilities that could
interfere with the detours. Check that adequate construction limits are provided to construct the detour. Review
the adequacy of detours should be checked for both vehicular traffic as well as pedestrian traffic.
Below is a link to the Manual on Uniform Traffic Control Devices:
18
Original Date: 1/3/94
Revised Date: 05/27/16
http://mutcd.fhwa.dot.gov/
103.5 CROSS SECTIONS
Cross sectional areas should be spot checked, and field investigation should provide comparison of existing
contours with those on the plans.
Any differences or other difficulties should be noted and discussed with your Engineering Supervisor.
Below is an example of a Cross Section sheet from Conway Road, near Bridge #206:
ILLUSTRATION 103.5 – SAMPLE CROSS SECTION SHEET
104 FIELD CHECK
An in-depth check of existing conditions should be made to determine the topographical accuracy of the
Construction Plans and to predetermine problem areas prior to the start of construction. Assistance of the
Survey Party may be required to field check various elevations. Most differences can be adjusted if discovered
prior to construction.
Items to be checked should include the following:
19
Original Date: 1/3/94
Revised Date: 05/27/16
(a) Existing drainage facilities to be used in conjunction with the new construction should be checked for
deterioration, location, settlement, joint displacement, blockage, proper capacity and adjustment
requirement.
(b) The composition and makeup of existing roadways should be checked for deterioration, areas of
instability, width and proximity of structures and utilities to remain in place.
(c) Existing water and gas services shutoff valves, meters and main shutoff and cathode boxes should be
noted and tied by distance to objects with will remain in place during the course of construction. Each
residential and commercial shutoff and meter box should be located and checked against plans. Forms
for location tie-out are available at the Construction Office.
(d) Topography, additions or removal of buildings, recent site grading, rock out crops, slope instability,
channel course changes or any addition of a permanent structure should be immediately brought to your
Engineering Supervisor’s attention.
(e) Clearance of objects and structures to remain in place should be checked. Both vertical and horizontal
minimum clearances must be maintained.
(f) Existing working septic systems and leach fields should be noted and immediately brought to your
supervisor’s attention. Sinkholes and French drains should be checked to see if capacity is adequate for
out fail drainage. Buildings and other improvements which are not shown on the plans should be noted
and provisions should be made to connect them into the new sewer system.
(g) The structural condition of bridges and box culverts to be used in place or as a part of a detour should be
checked. Needed maintenance or unsafe conditions should be noted and reported to your engineering
supervisor.
(h) The Resident Engineer should coordinate with their supervisor in notification to the local municipalities,
police, fire, school, and ambulance district offices prior to the start of construction concerning detours,
road closings and anticipated work scheduling. Adequate notice should be provided to these agencies
concerning the start of work.
(i) Conditions of any existing improvements which the contractor could damage during his work should be
noted for future reference. These could include curbs, sidewalks, driveways, subdivision markers, etc.
These items should also be covered in the project photographs taken prior to construction.
(j) Check for sprinklers.
(k) Construction limits should be checked to ensure that adequate area is provided to complete various work
under the contract, both permanent and temporary.
(l) Review the Right-of-Way file at 1050 North Lindbergh, if available, to check if items agreed to in the
negotiations are included on the plans or in Special Provisions.
105 DIGITAL RECORD OF PRE EXISTING JOB SITE
20
Original Date: 1/3/94
Revised Date: 05/27/16
A Complete set of digital pictures, or video, shall be taken of all properties within the construction limits,
existing project boundary’s, existing environmental conditions and any other preexisting condition that could be
beneficial to reference at a later date.
Before construction or utility relocation commences, a complete set of photographs, or recording, should be
made showing the existing conditions on centerline throughout the project, each private or commercial entrance,
exposed foundations, existing street approaches, markers, headstones, or entrance markers, and exiting damage
or cracks in sidewalks, house foundation, entrance approaches or outbuildings.
Trees, shrubs and vegetation to remain in place but in close proximity to grading areas should also be
photographed in case of root damage or other damage which might kill the plant after an extended period of
time. In areas where blasting or pile driving may occur, existing cracks in foundations, walkways and chimneys
should be documented and periodically re-photographed to sustain or reject damage claims.
In addition, any other item unique to the particular project which may be damaged by the contractor should be
photographed.
All digital photos should be stored on the computer, and on a separate CD or DVD and kept safe from scratches
with the hard copy project folder.
106 UTILITY RELOCATION
The utility relocation may commence prior to or during construction by the contractor. This work will be in
accordance with the Utility Relocation Plan as approved by the Department. The Utility Relocation Plan will
contain plans of relocations to be made, existing facilities to remain in place or to be abandoned, and will be
included in the Special Provisions in the contract. The RE should review the Utility Relocation Plan to ensure
that it does not conflict with the project Construction Plans or with other Utility Relocation Plans.
The RE is solely responsible for monitoring work being performed by utility companies in conjunction with the
project. During the course of construction, it may be necessary to alter or revise the Utility Relocation Plan in
regard to alignment or elevation of a particular utility to be adjusted or relocated.
This change should be made only under the following criteria:
(a) Any change should be discussed with the Engineering Supervisor and Utilities Coordinator.
(b) Changes should only be made if they are in the best interest of St. Louis County and within the limits of
good engineering practice.
(c) Changes do not impose a penalty on other utilities or the contractor at a later date.
(d) Changes do not represent a major departure from the scope or original intent of the Utility Relocation
Plan as approved.
Any changes in alignment or elevation should be recorded by the Survey Party Chief and shown on the As-Built
Plans, and the Engineering Supervisor and contractor should be notified. At the discretion of the Engineering
Supervisor, any major change proposed may have to be approved by the Special Use Permit Section prior to
commencement of the change.
21
Original Date: 1/3/94
Revised Date: 05/27/16
Utility relocations may be reimbursable, either totally or in part, to the utility involved. The Resident Engineer
will keep records of labor, equipment and material used as a check on future billings from the utility.
Reimbursable items should be noted on the Utility Relocation Plan.
107 CONSTRUCTION STAKING
The purpose of construction staking on the project is to establish alignment and elevation control for the
construction of specific portions of the total improvement. The RE must be very familiar with the construction
staking on the project, both as to theory and application.
All construction staking will be performed by a County or consultant Survey Party under the direct supervision
of a Party Chief who is responsible for the completion and accuracy of all staking performed.
Construction staking performed by a consultant Survey Party will likely be done by a subcontractor. The
Resident Engineer may not have direct access to such a Survey Party. Arrangements for construction staking
shall be made with the general contractor’s site representative.
Construction staking provided by County survey personnel shall be arranged with the Chief of Surveys. The
party Chief is supervised by the Chief of Surveys who will coordinate work needed between several
construction projects and other duties. Because of manpower limitations and variable workloads, the Resident
Engineer should attempt to provide at least a 2 day notice of upcoming staking needs. To accomplish this, the
contractor should be consulted as to staking needs for his own and subcontractor’s work on a daily basis. An
awareness by the Resident Engineer and inspection personnel of the various construction elements performed
and planned for implementation is imperative. The RE should pay close attention to work done by the Survey
Party in an attempt to detect errors. Special attention should be paid to critical areas such as bridge alignment
and construction.
The RE is encouraged to request that the Party Chief provide the RE with cut sheets, bench marks, reference
points, cross sections and level notes to aid in the construction of the project and provide a reference in the
absence of the Party Chief.
107.1 MATERIALS FURNISHED BY CONTRACTOR
The contractor is charged with providing the materials necessary for the staking of the project. As a first order
of business the necessary materials should be itemized as to specific item, size, brand designation and number
required to aid the contractor in their acquisition. Prompt compliance with this itemized list is required. The
Project Superintendent should be given the list which is prepared by the party Chief.
107.2 PRECONSTRUCTION LAYOUT
As a general rule, the following procedures and staking methods are utilized on all County projects:
The preliminary layout work on construction projects is performed by County forces or, more often, by
consultant engineers as a part of the development of Construction Plans and Right-of-Way acquisition Plans.
The consultant engineer, through contractual arrangement, provides reference ties and other control devices for
the project. This would include establishing the project centerline, baselines for ramps and detours, centerlines
and working lines for structure, right-of-way corners and angle points and elevation control in the form of bench
marks based on United States Geological Survey (USGS) datum.
22
Original Date: 1/3/94
Revised Date: 05/27/16
Prior to the start of construction, the Survey party will reestablish the construction centerline points of
curvature, points of tangency, ramp baselines and centerlines of structures, as needed and determined by the RE.
Centerlines and baselines will be staked in 100 foot intervals and at 50 foot intermediate points. These station
points will provide the required alignment for utility relocation and serve to locate all items of construction of
the project. (Note: As a general rule, stationing runs from south to north and from west to east.) Pay special
attention to any equations in the centerline stationing (i.e. 105+25 Back = 105+35 Ahead).
107.3 CLEARING LIMITS
Prior to the beginning of construction, the Survey Party may, if necessary, provide staking which will demarcate
the right-of-way (commonly written as R/W) and establish clearing limits for tree and vegetation growth
removal (commonly written C/L, not to be confused with Center Line). As a check, the clearing stake should
fall at the toe or top of slopes and is shown on the plan sheets of the Construction Plans as a dotted line denoted
with a C/L superscription.
107.4 SITE BENCH MARKS
Prior to the beginning of construction, the Survey Party will run an elevation circuit to establish the accuracy of
all bench marks shown on the plans. Any variation in location or elevation should be shown on the plan sheets
of the Construction Plans. It is very important that the Resident Engineer be familiar with the location of bench
marks on the project, and it is essential that bench mark elevations be shown on the plans of the Resident
Engineer and all construction inspectors.
Bench marks established for elevation control at structures should meet the following criteria:
(a) Only one bench mark should be set for each structure and only that bench mark should be referred to.
(b) The elevation of the bench mark should be clearly marked so the elevation is readily available to all
participants in the construction process.
(c) The bench mark should be a formidable object (i.e. a railroad spike or a square on existing headwall not
easily moved or vandalized). The bench mark should be so situated as to allow ready access and direct
backsights. The bench mark should be located on a solid, fixed object which will remain unmoved by
vibration or adjacent construction.
(d) Occasional checks by elevation circuit should be made by the Survey Party to verify the constancy of the
bench mark. Where structures are adjacent or visible, one to the other, the bench marks must be
checked to assure compatibility for connecting roadways. Always be sure to check each unit of a
structure for proper elevation. Then double check.
107.5 PROPERTY CORNERS AND MONUMENTATION
The policy of St. Louis County is not to stake any property corners for private or commercial properties.
Normally, the settlement provided during R/W acquisition does include cost necessary to reestablish these
corners. As required by St. Louis County Ordinance, the Survey Party will establish right-of-way limits at the
end of the project by means of monuments. These monuments will establish the boundary of the road right-ofway and will establish points of curvature and tangency and angle points as shown on the plans. During the
23
Original Date: 1/3/94
Revised Date: 05/27/16
pre-construction investigation, any existing monuments or corners should be noted and the Party Chief notified
to allow for reference ties to be placed. It is illegal to knowingly move, remove, deface or destroy any corner of
the United States Public Land Survey System, property boundary marker, bench mark or horizontal control
monument; therefore, care should be taken to notify the chief of Surveys when a corner is encountered.
107.6 USGS, MSD AND OTHER BENCH MARKS
Should USGS, St. Louis County or other bench marks be destroyed during the construction of the roadway or
the demolition of a bridge or box culvert, the Chief of Surveys must be notified immediately. It is the policy of
St. Louis County not to reset USGS bench marks but rather to set St. Louis County tablets in their place. This
replacement tablet will be provided by the Chief of Surveys and should be poured in place at a site designated
by him. As St. Louis County maintains a directory of bench marks within St. Louis County, it is imperative to
maintain all existing bench marks and establish new bench marks to replace demolished ones.
108 FIELD MEETING PRIOR TO PRECONSTRUCTION CONFERENCE
Prior to the Preconstruction Conference, the Resident Engineer and the Utility Coordinator will meet with the
contractor’s representative and any affected utility companies at the job site to discuss any conflicts that will
affect the contractor’s scheduling of the project. The purpose of this meeting is to make all parties aware of
these conflicts and to coordinate and discuss solutions prior to the Pre-Construction Conference.
109 PRECONSTRUCTION CONFERENCE
A Preconstruction Conference will be held prior to the start of construction on each project. The purpose of this
conference is to discuss the implementation of temporary and permanent erosion control work, to discuss
coordination efforts required for utility relocations, discuss logistics of construction phasing, discuss known
plan and specification issues or known changes that will need to be made, provide contractor with additional
sets of plans and specifications, discuss material concerns and discuss survey needs, as appropriate.
Below is a link to an actual recorded Pre-Construction conference for Shackelford Widening CIP project,
recorded in Spring of 2016:
http://Link_to_be_added_after_Shackelford_Preconstruction_Meeting (not yet active)
Also provided below is an example Preconstruction Agenda, some parts may not be relevant for all types of
projects, use only the sections relevant to your project during the meeting.
24
Original Date: 1/3/94
Revised Date: 05/27/16
Pre-Construction Conference Agenda
AR/CR ####
Short Job Description
Contract No.:
Date:
Fed No.:
Time: Location:
(Note: “This meeting may being audio/video recorded
and will become part of the construction project records.”)
Note: Any sections not needed for this project may be deleted.
Forms for Consultant and Contractor Staff are located at:
http://www2.dot.state.fl.us/proceduraldocuments/forms/forms.asp
1. Introductions
A. Name, Company;
B. Please make sure that everyone has signed the attendance list.
2. Description of Project
A. This project consists of
Contractor:
Total Contract Amount: $
Contract Calendar Days:
__________________________
__________________________
________
3. Important Dates
A. Project Award:
B. Execution:
C. Notice to Proceed:
D. First Chargeable Contract Day will be:
E. Contractor’s anticipated start date:
4. Delineation of Lines of Authority
A. Contacts:
City of ? / County
Agency Contact/Project Manager
Project Administrator
Inspectors
_________________
_________________
_________________
_________________
_________________
NAME
PHONE
NAME
PHONE
Office Specialist
CONTRACTOR
Project Manager
Superintendent
Forman
QC Representatives
25
Original Date: 1/3/94
Revised Date: 05/27/16
EMERGENCY CONTACTS (DAY AND NIGHT)
NAME
COMPANY
PHONE
5. Progress Meetings
A. Agreed upon date, time and location (Utilities Meetings will be combined with Progress Meetings).
6. Project Bulletin Board
A. Location of Board – needs to be permanently fixed where employees gather
B. Below is a link to the Project Bulletin Board Checklist:
1) http://www.modot.org/business/contractor_resources/documents/JobSiteBulletinBoardChecklistre
vised12-15-1.pdf
7. Utilities
A. Utility company comments
1) Status of each utility
2) Point of contact and phone number
B. Resident Utility Coordinator comments
1) Review of Utility Issues
C. Contractor comments
D. Excuse Utility Representatives
8. Construction Schedule / Progress Chart Submittals
A. Submission of Work Schedule”-“Schedule Submissions” of the Special Provisions.
1) Submit to the engineer within 21 calendar days after execution of the Contract or at the
preconstruction conference, whichever is earlier.
a) Monthly updates of the Contract Schedule are to be submitted within 7 calendar days
before the monthly estimate cut-off date.
B. Night work, Day Work
C. Provide updated schedules at the progress meetings on monthly cutoff dates.
D. Provide two-week look ahead schedules at the progress meetings.
E. If the time granted by Supplemental Agreement is 15 days or greater a Revised Schedule is required.
9. Maintenance of Traffic (plans review and discussion)
A. Lane Closure Restrictions
B. Discussion of MOT Phasing
C. MUTCD Material Quality requirements
10. Review of Plans and Special Requirements
A. Any errors or omissions noted by the contractor.
B. Special Project Requirements
11. Bridge Work
A. Contractor’s Quality Control (QC) Plan
B. Pile Installation Plan
C. Drilled Shaft Installation Plan
D. Any rigging and/or shoring plans
26
Original Date: 1/3/94
Revised Date: 05/27/16
E. Schedule pre-work meetings that are pertinent to the project with all involved parties prior to initial / major
construction activities (i.e. “General Structural Concrete Pour”, “Bridge Beam”, “Bridge Deck Pour”, etc.).
12. Asphalt Paving by –
, Resident Asphalt Specialist
A. Pre-paving Meeting to be held
B. 5 day minimum notice given to RE and Materials Engineer before any paving will be allowed.
13. Materials
A. Discuss materials precon package.
B. Discuss time frame for submittal, review and approval.
C. Discuss ordering procedures and how early to place orders
D. How many plants will used and does the contractor have a backup plan in case a plant breaks down?
14. Erosion Control and SW Pollution Prevention Plans
A. Rules and rules, policies, guidelines and BMP’s can be found at
http://www.stlouisco.com/YourGovernment/CountyDepartments/Transportation/TransportationPublication
sManuals/SedimentandErosionControl
B. If required, all permits must be posted
C. Contractor is required to inspect and maintain controls weekly and within 24 hours after a rainstorm in
excess of 0.50 inches. The contractor shall report all inspection findings and corrective actions taken as a
result of the inspection. Rain event inspection forms will be completed by the Engineer and delivered to
the Contractor for immediate maintenance of disturbed or failing BMP’s. Once a BMP repair need is
identified and the site is accessible by contracting equipment, the contractor will have 5 working days to
repair the deficiency.
D. Below is a link to the “Major Land Disturbance Special Inspector’s Weekly Inspection Report:
1) http://www.stlouisco.com/Portals/8/docs/document%20library/public%20works/code%20enforcem
ent/permits/land-dist/Land-Dist-Spec-Insp-Wkly-Rpt.pdf.
15. Subletting Work/Rental Agreements/Purchase Orders/Letters of Entry
A. Have the certifications been submitted?
B. Sublet work cannot exceed 50% of the total contract price
C. List of subcontractors.
D. Procedures for Rental Agreements/Purchase Orders/Letters of Entry (DOT Form 700-010-11)
16. Contract Time
A.
Days
B. Alternative Contract; review provision and incentive/disincentive bonus if applicable.
C. Holidays
D. Weather Days – In accordance with Specification One day of inclement weather = One day of time
granted.
17. Requested Documentation from Contractor
A. The following documentation need to be submitted:
1) CPM Schedule(s) or work progress schedule as required by the contract.
2) List of subcontractors.
3) Shop Drawing Schedule of Submittals (w/in 60 days of contract start).
4) Lighting Plan showing the type and location of lights to be used for night work.
5) Erosion Control Plan
6) Producer Supplier List.
7) All concrete and asphalt mix designs to be used on the project
27
Original Date: 1/3/94
Revised Date: 05/27/16
8) Maintenance of traffic plans
9) Emergency phone list
a) CC’s on letters to law enforcement agencies and emergencies response agencies (such
as fire department and ambulance service).
10) Letters to local police, fire and ambulance departments nearby the project.
11) Air Redosing Plan
12) Pile Installation Plan
13) Drilled Shaft Installation Plan
18. Estimates
A. Provide Monthly Estimate Cut-Off dates to the contractor. Dates can also be found at the following link
http://www.dot.state.fl.us/construction/CONSTADM/EstimatesCutOff.shtm
B. Request for Partial Payment for Stockpiled Material
1) Request for Payment for Stockpiled Materials due with the required documentation At least 5
working days before a monthly cut off.
19. Pre-Work Meetings
A. Schedule meetings with all involved parties prior to initial / major construction activities. Check off
Agendas listed below that are pertinent to the project, and should have meetings scheduled.
B. Pre-Work Agendas
 Utility Pre-Work Agenda
 Earthwork Pre-Work Agenda
 Drainage Pre-Work Agenda
 Pre-Paving Conference Agenda
o Pre-Paving Conference Minutes Amendment
 MSE Wall Pre-Work Agenda
 General Structural Concrete Pour Pre-Work Agenda
 Mass Concrete Pre-Work Agenda
 Concrete Pavement Pre-Work Agenda
 Concrete Bridge Deck Pre-Work Agenda
 Drilled Shaft Pre-Work Agenda
 Piling Pre-Work Agenda
 Sheet Pile Pre-Work Agenda
 Auger Cast Piling Pre-Work Agenda
 Bridge Beam Pre-Work Agenda
 Post-Tensioning & Grouting
 Pavement Marking Pre-Work Agenda
 Sign Installation Pre-Work Agenda
 Signalization Pre-Work Agenda
 Traffic Monitoring Site (TMS) Pre-Work Agenda
o TMS Handouts
 PTMS Checklist
 PTMS Testing Minimums
 PTMS & TTMS Inspection Sheet
 Intelligent Transportation System (ITS) Pre-Work Agenda
 Lighting Pre-Work Agenda
o Excuse Representatives not needed for EEO Meeting
20. General Discussion – Q&A
28
Original Date: 1/3/94
Revised Date: 05/27/16
21. Meeting was adjourned at
29
Original Date: 1/3/94
Revised Date: 05/27/16
SIGN-IN SHEET FOR PRE-CONSTRUCTION CONFERENCE
PLEASE PRINT
NAME
COMPANY
E-MAIL
PHONE
30
Original Date: 1/3/94
Revised Date: 05/27/16
109.1 SPEACIAL ITEMS
The following should be provided by the RE for use at the Preconstruction conference:
(a) Anticipated relocation schedule of the various utilities, estimated projected start and
completion dates and any conflict causing a delay in starting the project.
(b) Particular interest should be paid to utility relocation. A notation of location from center
line for each utility versus proposed construction should be investigated with any
conflicts noted for correction and/or possible adjustments.
(c) A listing of required certifications of materials should be provided for the contractor at
the preconstruction conference.
(d) Additional Contract Books
The following items are to be submitted by the contractor and approved prior to
commencement of work:
(a) The contractor’s schedule for the implementation of temporary erosion and sediment
control work.
(b) List of proposed subcontractors, item numbers from contract of work to be sublet and
contract prices of item. List of minority subcontractors with dollar amount sublet to
ensure that proper percentages are met.
(c) List of material suppliers and materials they will supply.
(d) Proposed Project Superintendent (with resume).
(e) Bar Chart of construction schedule.
(f) Equal Employment Opportunity (EEO) policy statement and EEO officer.
(g) Non-Discrimination Notice.
Items to be submitted during construction:
(a) Certified payrolls for the prime contractor and the subcontractors (one for every week the
prime or subcontractors are working). These are to be submitted weekly by the
contractor and checked weekly by the RE. Early review of submitted payrolls will allow
for timely corrections should any inconsistencies be found.
(b) Material certifications are to be submitted prior to their use on the project.
31
Original Date: 1/3/94
Revised Date: 05/27/16
(c) Letters showing that the prime and subcontractors employ licensed personnel.
(d) Copy of Permit from MSD for sewer work on the project (if necessary)
(e) Bulletin Board information
(f) Certificates of Insurance for Subcontractor.
(g) Shop drawings as required
(h) Proposed location of waste disposal sites.
(i) Letters of permission from any property owners near the project whose private property
will be used to park equipment or store materials.
(j) EEO form PR-1391 must be submitted during the first week of August for work
completed in the last pay period of July (Federal Projects)
110 RELATED PROJECT CORRESPONDENCE
110.1 TEMPORARY EROSION AND SEDIMENT CONTROL
Provisions requiring a specific temporary erosion and sediment control plan are incorporated in
the Special Provisions of the contract. The contractor shall submit his schedules for the
implementation of the temporary erosion and sediment control work for approval. No work shall
be started until the erosion control sequences and method of operations have been approved.
The RE may limit the amount of surface area of erodible earth material exposed by the
construction until permanent or temporary pollution control measures are installed. Such work
may involve the construction of temporary berms, dikes, sediment basins, slope drains and the
use of temporary mulched seeding or other control devices or methods as necessary to control
erosion. Be sure to check the contract as some items may be pay items. The following link
provides Sediment and Erosion Control guidance.
http://www.stlouisco.com/YourGovernment/CountyDepartments/Transportation/TransportationP
ublicationsManuals/SedimentandErosionControl
110.2 SUBCONTRACTOR APPROVAL REQUEST
This correspondence is to be submitted by the prime contractor for each subcontractor utilized in
the construction of the project. This submittal must be approved by the Department before any
work can be performed by the designated subcontractor.
32
Original Date: 1/3/94
Revised Date: 05/27/16
Each subcontractor’s approval will be based on past performance or, if insufficient information is
available, a resume detailing previously completed projects, personnel, experience and
equipment will be required.
Approval of any subcontractor does not relieve the prime contractor of any direct or implied
liability for compliance with the plans and Specification. Failure to provide quality construction,
adequate on job safety precautions or compliance with EEO or other minority employment
requirements may result in retraction of this stated approval. The letter requesting approval of a
subcontractor should contain the following information:
(a) Name of proposed subcontractor
(b) Item or items of work to be performed
(c) Contract unit price of each item (if other than plan unit price, also provide explanation for
partial payment)
The department will provide a letter of approval for the subcontractor to the prime contractor
stating:
(a) Line items the subcontractor is approved for.
(b) List of approved specialty item.
(c) Percentage of the project sublet (prime must perform at least 50%)
(1) Items listed as specialty are not included in the subcontractor approval percentage
110.3 MATERIAL SUPPLIER APPROVAL REQUEST
This correspondence is to be submitted by the prime contractor for each and every material item
to be used in the construction of the project. This letter should be submitted prior to
construction involving the particular item being requested for approval.
Approval of any item for inclusion in the project is always tentative, dependent on continued
compliance with the specified standards and the requirements of the specifications.
Approval of any material supplier does not relieve the prime contractor of any requirements for
independent testing, chemical analysis, certification, or on job sampling.
The letter of request from the contractor for approval should contain the following:
(a) The supplier’s name, the specific plant or plants that the contract requests to use, the
name of the item supplied, any pertinent information on any unused product specified for
use in the contract Special Provisions
33
Original Date: 1/3/94
Revised Date: 05/27/16
The letter of supplier approval from this Department should contain specific approval of
the supplier per item, certain tentative approval contingent on specified reason and/or
request for additional information.
110.4 SUPERINTENDENT
The prime contractor is responsible for all the work in progress, and the prime contractor will
name a Project Superintendent. The Project Superintendent shall be a competent and reliable
person who shall have final authority to act for the contractor. He is the counterpart of the
Resident Engineer. The Project Superintendent must be present on the job site when all work by
the prime contractor and/or subcontracts is being performed. The Project Superintendent is the
contact person for all negotiations with the contractor. He is responsible for signing the Weekly
Reports, Force Accounts and Change Orders, coordination of subcontractors and suppliers and
all insurance claims and Safety matters.
The name of the Project Superintendent and other designated corporation agents may be
contained in the contract documents. These persons must be able to obligate the owner or
corporation in binding legal manners. The letter requesting approval of a Project Superintendent
should contain the name, work experience and personal resume.
110.5 BAR CHART FOR CONSTRUCTION SCHEDULE
This correspondence is to be submitted by the prime contractor prior to or at the PreConstruction Conference. The Bar Chart should plot the prosed progress of the major items of
the project vs the working days required for the construction of the project. It should also be tied
into calendar days so that a completion date for the project is shown.
Approval of the Bar Chart by this Department obligates the contractor to a schedule of
manpower and equipment utilization which will closely compare to the proposed item
completion dates enumerated. The RE should periodically check this production schedule
against actual production. The contract should be advised of any substantial deviation from the
production schedule. This information should also be given to the engineering supervisor. In
general, failure by the contractor to remedy this imbalance will result in correspondence being
directed to his attention from the Highway Construction Engineer with notification extended to
the bonding company.
110.6 EQUAL EMPLOYMENT OPPORTUNITY
The contractor shall take specific affirmative action to ensure EEO as outlined in the contract.
The contractor must adopt an EEO operation policy as stated in the contract, or one of equal
coverage, and transmit a copy to this Department.
The contractor shall designate a responsible official to monitor all employment related activity to
ensure that the company EEO policy is being carried out.
34
Original Date: 1/3/94
Revised Date: 05/27/16
110.7 NON-DISCRIMINATION
The contractor will not discriminate against any employee or applicant for employment because
of race, color, religion, sex or national origin. A copy of the contractor’s Notice to the Unions
regarding the contractor’s commitment shall be posted on the Bulletin Board and a copy
furnished to the RE.
111 NOTICE TO PROCEED
The Notice to Proceed is a legal document which informs the contractor when he is to commence
construction operations on the project. The Notice to Proceed date also establishes the start date
from which working days will begin to be counted.
Commencement of work on a project remains contingent on the following factors have occurred:
(a) Approval of the prime contractor by the County Council and contract books signed by the
County Executive and, if the project is federally foundered, by the Federal Highway
Administration.
(b) Award of the contract by the County, executed by the contractor and submitted to the
County.
(c) Filing by the contractor of the specified performance bond.
(d) Approval of the contractor’s erosion control plan.
(e) Filing of an adequate Certificate of Insurance policy for the prime contractor
(f) Approval of the designated Project Superintendent.
(g) Approval of any material supplier or subcontractor to be employed for work at this time.
(h) Contractor obtaining permit from MSD for sewer work to be performed on the project (if
applicable)
(i) Posting of Project Bulletin Board
(j) Installation of office trailer by contractor where applicable.
112 NOTICE TO PROPERTY OWNERS
Prior to the start of the construction, the RE will place a notice to Property Owners, indicating a
contractor is about to start work, on the affected property owners door. This Notice to Property
owners will not be placed in, on or around any mailboxes. The RE will supply the project
35
Original Date: 1/3/94
Revised Date: 05/27/16
information to the Construction Office and the Notice to Property Owners will be typed using
this information. Plastic door bags are available at the Construction Office in which to place the
Notice to Property owners. On multiple sites, the Notice to Property owners will have to be
revised to keep the anticipated construction dates current.
An example letter can be found using the following links:
http://countynet.stlouisco.net/Departments/HwysPubWorks/Construction/default.aspx?RootFold
er=%2fDepartments%2fHwysPubWorks%2fConstruction%2fShared%20Documents%2fProjects
%20%2d%20Jesse%20Jonas%2fProjects%202015%2f2015%20Concrete%20Replacement%20
D%2c%20CR%2d1611%2fBag%20Letter&FolderCTID=&View=%7b239C8641%2dD177%2d
49DB%2dA53D%2dC14AC1B8ABC1%7d
or
http://countynet.stlouisco.net/Departments/HwysPubWorks/Construction/Shared%20Documents/
Forms/AllItems.aspx?RootFolder=%2fDepartments%2fHwysPubWorks%2fConstruction%2fSha
red%20Documents%2fQRG%5fForms%5fLinks%2fForms%2fCommon%20Forms&FolderCTI
D=&View=%7b530867D5%2d2971%2d4BFD%2d9859%2d8470EC9901E9%7d
113 WASTE DISPOSAL SITES AND BORROW AREAS
The contractor must submit a list of waste disposal sites for approval prior to their use. The
request for approval shall include the location of the waste disposal site; property owner’s
permission to place waste material on his property (which includes a statement that relieves St.
Louis County of any liability for the placement of the material on this property) and the property
owner’s mailing address if different from the waste disposal site location. If the waste disposal
site is located within the boundaries of a municipality, the contractor must also obtain permission
form the municipality to use this site. The Mayor or City Administrator of the municipality in
question must sign and approve the waste disposal site location. In addition, disposal sites shall
not be located in floodplain areas, and proof that the site is not in a floodplain may be required.
Locations of proposed borrow areas should also be submitted for approval with letters of
permission from affected property owners. Borrow areas must be submitted for approval
sufficiently ahead of time to allow for sampling by Materials Testing Laboratory personnel so
that a proctor may be obtained.
36
Original Date: 1/3/94
Revised Date: 05/27/16
SECTION 200
EARTHWORK AND EXCAVATION
201 CONSTRUCTION STAKING
The purpose of construction staking on the project is to establish alignment and elevation control
for the construction of specific portions of the total improvement. The RE must be very familiar
with the construction staking on the project, both as to theory and application.
All construction staking will be performed by a County or consultant Survey Party under the
direct supervision of a Party Chief who is responsible for the completion and accuracy of all
staking performed.
Construction staking performed by a consultant Survey Party will likely be done by a
subcontractor. The Resident Engineer may not have direct access to such a Survey Party.
Arrangements for construction staking shall be made with the general contractor’s site
representative.
Construction staking provided by County survey personnel shall be arranged with the Chief of
Surveys. The party Chief is supervised by the Chief of Surveys who will coordinate work
needed between several construction projects and other duties. Because of manpower limitations
and variable workloads, the Resident Engineer should attempt to provide at least a 2 day notice
of upcoming staking needs. To accomplish this, the contractor should be consulted as to staking
needs for his own and subcontractor’s work on a daily basis. An awareness by the Resident
Engineer and inspection personnel of the various construction elements performed and planned
for implementation is imperative. The RE should pay close attention to work done by the Survey
Party in an attempt to detect errors. Special attention should be paid to critical areas such as
bridge alignment and construction.
The RE is encouraged to request that the Party Chief provide the RE with cut sheets, bench
marks, reference points, cross sections and level notes to aid in the construction of the project
and provide a reference in the absence of the Party Chief.
201.1 MATERIALS FURNISHED BY CONTRACTOR
The contractor is charged with providing the materials necessary for the staking of the project.
As a first order of business the necessary materials should be itemized as to specific item, size,
brand designation and number required to aid the contractor in their acquisition. Prompt
compliance with this itemized list is required. The Project Superintendent should be given the
list which is prepared by the party Chief.
37
Original Date: 1/3/94
Revised Date: 05/27/16
202 CONSTRUCTION LAYOUT
As a general rule, the following procedures and staking methods are utilized on all County
projects:
The preliminary layout work on construction projects is performed by County forces or, more
often, by consultant engineers as a part of the development of Construction Plans and Right-ofWay acquisition Plans. The consultant engineer, through contractual arrangement, provides
reference ties and other control devices for the project. This would include establishing the
project centerline, baselines for ramps and detours, centerlines and working lines for structure,
right-of-way corners and angle points and elevation control in the form of bench marks based on
United States Geological Survey (USGS) datum.
Prior to the start of construction, the Survey party will reestablish the construction centerline
points of curvature, points of tangency, ramp baselines and centerlines of structures, as needed
and determined by the RE. Centerlines and baselines will be staked in 100 foot intervals and at
50 foot intermediate points. These station points will provide the required alignment for utility
relocation and serve to locate all items of construction of the project. (Note: As a general rule,
stationing runs from south to north and from west to east.) Pay special attention to any equations
in the centerline stationing (i.e. 105+25 Back = 105+35 Ahead).
202.1 CLEARING LIMITS
Prior to the beginning of construction, the Survey Party may, if necessary, provide staking which
will demarcate the right-of-way (commonly written as R/W) and establish clearing limits for tree
and vegetation growth removal (commonly written C/L, not to be confused with Center Line).
As a check, the clearing stake should fall at the toe or top of slopes and is shown on the plan
sheets of the Construction Plans as a dotted line denoted with a C/L superscription.
202.2 BENCH MARKS
Prior to the beginning of construction, the Survey Party will run an elevation circuit to establish
the accuracy of all bench marks shown on the plans. Any variation in location or elevation
should be shown on the plan sheets of the Construction Plans. It is very important that the
Resident Engineer be familiar with the location of bench marks on the project, and it is essential
that bench mark elevations be shown on the plans of the Resident Engineer and all construction
inspectors.
Bench marks established for elevation control at structures should meet the following criteria:
(a) Only one bench mark should be set for each structure and only that bench mark should
be referred to.
38
Original Date: 1/3/94
Revised Date: 05/27/16
(b) The elevation of the bench mark should be clearly marked so the elevation is readily
available to all participants in the construction process.
(c) The bench mark should be a formidable object (i.e. a railroad spike or a square on
existing headwall not easily moved or vandalized). The bench mark should be so situated
as to allow ready access and direct backsights. The bench mark should be located on a
solid, fixed object which will remain unmoved by vibration or adjacent construction.
(d) Occasional checks by elevation circuit should be made by the Survey Party to verify the
constancy of the bench mark. Where structures are adjacent or visible, one to the other,
the bench marks must be checked to assure compatibility for connecting roadways.
Always be sure to check each unit of a structure for proper elevation. Then double check.
202.3 SLOPE STAKES
The slope stake is set to identify the point at which a roadway fill of a given height on a set slope
will intercept the existing ground line. This point is called the toe of the slope. In contract, the
slope stake is also set to identify the point at which a roadway cut of a given depth on a set slope
will intercept the existing ground line. The point is called the top of slope. The slope stake is set
to enable the contractor to perform rough grading operations on the project (rough grading being
defined as + 0.3 foot). The slope stake is set by determining the shoulder point elevation in
relation to the then existing ground elevation at the theoretical slope intercept. Knowing the
centerline elevation, it is possible to determine the shoulder point elevation by observing the
typical section cross slopes, curb sections and distances to the shoulder point. In portions of the
roadway with a constant typical section, a constant shoulder point distance and elevation can be
obtained. By knowing the desired slope of the cut or fill section, a distance and elevation to the
intercept at the original ground line can be computed. By taking a trial ground shot at the
computed distance, a determination of actual distance and elevation to the slope intercept point
can be established. While setting the slope stakes, a cross section should be randomly taken to
check the accuracy of the cross section shown on the plans. In areas which do not match the plan
cross section, a new set of cross sections should be taken to provide accurate earthwork
quantities. The typical slope stakes as set in the field will be of wood, 1 by 4 inches, 12 to 18
inches in length, with a sharpened point. The information contained on the slope stake will be as
shown in illustration 202.3
39
Original Date: 1/3/94
Revised Date: 05/27/16
ILLUSTRATION 202.3 – TYPICAL SLOPE STAKE INFORMATION
The contractor should be cautioned to provide protection for these and all construction staking.
The specifications provide action to be followed for failure to preserve and maintain these stakes.
202.4 CROSS SECTIONS
Cross sections are found in the project Construction Plans and are the basis of determination for
all earthwork quantities. The purpose of the cross section is to provide an end view of the road
way section. By an average summation of the end view surface areas of adjacent sections
multiplied by the distance between adjacent sections, a volume of cut material or fill material can
be computed. By compiling these volumes, a total volume of excavation or embankment
quantity can be calculated. Cross sections show the original ground line as a dashed line in the
sections and are normally taken every 100 feet and at 50 foot intermediate points. Additional
cross sections are taken at drive approaches, street approaches, channels and other points of nonconformity compared to the typical end section for a normal 50 foot distance.
Besides providing a means of earthwork computation, the cross section also provides a means of
establishing a profile view of driveways and entrances intersecting the mainline. The cross
section also shows the typical roadway section, right-of-way, approximate top of toe of slope and
elevations at a particular point.
When the Resident Engineer receives the Construction Plans for the project, the cross sections
should be compared to the typical section to ascertain the accuracy of the one as opposed to the
other. Centerline elevations should also be checked as opposed to profile grade on centerline. A
visual check of the topography of the project as opposed to the cross sections in the plans should
reveal any gross errors in the original ground line. With the establishment of slope stakes by the
Survey Party, it will be possible to further check the accuracy of the original ground line. In any
40
Original Date: 1/3/94
Revised Date: 05/27/16
areas where the original cross sections prove to be inaccurate, off by 1 foot or more, a new set of
cross sections should be made. These new sections should indicate the centerline elevation,
gutter line, or should line elevations, top of slope or toe of slope elevation, ditch flow line
elevation and all points of grade breaks or vertical offset in elevation. These new cross sections
should be taken at the stationing point shown for the former section or at points of major
elevation change not previously shown. The Resident Engineer is responsible for reducing the
field notes, plotting and computing these cross section volumes.
For ease of computation, cross sections should always be taken perpendicularly to the centerline
or baseline and to a distance left or right of the centerline which will ensure a closed complete
section. In the event two cross sections should overlap (i.e. mainline cross sections and channel
cross sections), a common distance should be established to the point of intersection and a butt
line established between the two sections to ensure accuracy in volume calculations. Care
should be taken to ensure that all areas of possible excavation are covered by cross sections.
Side streets and entrances with large side slopes should be cross sectioned separately and butt
lines established to ensure accurate volume calculation.
A 00 section should be established to demarcate the original ground conditions in an undisturbed
state. The 00 section will always be required to begin or end a series of sections unless the
beginning or ending section commences or ends at a butt line. The distance from the 00 section
to the next section will not always be 50 feet but will reflect the distance from the section to
undisturbed original ground.
202.5 ROCK SECTIONS
For sections to be taken in rock (of whatever classification), preliminary 3 point sections should
be taken to determine the centerline elevation and shoulder elevations in relation to these
elevations as shown on the plans. The contractor will schedule the determination of top of rock
by drilling or spot excavation in advance of major excavation so that revisions in the slope stakes
can be made based on the actual field elevations, not plan elevations. Any major discrepancy in
the top of rock elevation (+/- 1 foot) should be reported to your supervisor immediately.
203 DETERMINING QUANTITY
Intentionally left blank
204 WASTE DISPOSAL SITES AND BORROW AREAS
On the majority of projects, the volume of excavation or embankment will not balance and
material will either have to be disposed of or borrowed off site. This situation is discussed in
Section 100 and Special Provisions will be provided in your contract documents. Reference St
Louis County’s Sediment and Erosion Control Manual for inspection and monitoring
requirements:
41
Original Date: 1/3/94
Revised Date: 05/27/16
http://www.stlouisco.com/YourGovernment/CountyDepartments/Transportation/TransportationP
ublicationsManuals/SedimentandErosionControl
205 MISCELLANEOUS ITEMS
Prior to starting any grading operation, the Resident Engineer should be familiar with the
appropriate items which can be found in the Specifications or the Special Provisions:
(a)
(b)
(c)
(d)
(e)
(f)
Clearing and grubbing.
Removal
Temporary erosion and sediment control
Borrow sites
Waste sites
Obtaining Proctor results for material testing
206 SUBGRADE
206.1 DIRT SUBGRADE (CONCRETE)
The inspection of concrete pavement begins with the proper preparation of the dirt subgrade.
The major problem which will be encountered in preparation of the dirt subgrade will be soil
stability. Compaction of the subgrade must be obtained in each lift of material placed. The
degree of compaction is proportional to moisture content and soil classification as is stability.
Any area of instability in the subgrade is to be removed and replaced with stable material.
Material may be removed up to 24 inches in depth to obtain stability. In those areas where
instability is caused by excessive moisture, aeration of the subgrade may be required to obtain
the optimum moisture for compaction. Failure to provide natural drainage during grading
operations at the end of the workday may cause ponding after a period of rain. Failure to pump
or drain the area as soon as possible will cause wet or soft areas that will require replacement
with dry dirt or other means at the expense of the contractor. Where excessive moisture is a
result of subterranean drainage, a French drain or underdrain system may be required to remove
excessive moisture form the grade. When instability is caused by soil classification (sands and
organic silts), removal and replacement with rock backfill or other approved backfill is the best
option.
Subgrade preparation is crucial in preparing the subgrade to support the pavement uniformly.
Pay particular attention to sections of the subgrade overlying culvert installations or any utility
installation such as sewer, telephone cables, power conduits and water lines. Carelessness in
backfilling utility trenches will cause troublesome soft spots in the subgrade. Also, density
requirements vary near culvert and bridge structures.
When a compacted, stable subgrade is obtained, the proper grade and cross slope must be
developed. Paving grades will be established to produce the desired roadway alignment,
elevation and configuration. Regardless of the method used to establish the final subgrade, the
42
Original Date: 1/3/94
Revised Date: 05/27/16
paving grade hubs will provide the only means of checking these items. A longitudinal string
line should be set early to provide a check of the individual grade stakes that may have been
disturbed or misread. Minor adjustments can be made to the string line to obtain a proper grade
line, or the Survey Party may be needed to check any appreciable variances.
Inspection of the subgrade will include:
(a) Alignment – The roadway width will be determined from the offset distance stated on
the paving grade stakes.
Adequate width for form setting or for the travel width of slip form equipment must also
be taken into account when establishing the graded width of the roadway. In cut areas or
surcharged areas, care must be taken to lay slopes back sufficiently to clear the widest
point on the paving equipment. (Also check for drainage structures and utility
appurtenance clearance).
(b) Elevation – The paving grade stakes will provide the finished pavement grade at the edge
of pavement or centerline.
The finish subgrade for dirt will be the pavement thickness plus the base course thickness
(if required) subtracted from the pavement grade. This grade should be checked by
string line and ruler at the indicated graded intervals (25 feet, 50 feet or odd stationed
grade hubs). When conventional paving methods are used, a pin will be placed at edge
of pavement and at centerline and graded in a accordance with the hub as established.
The grade established on the pin will be finished pavement. By stretching the string line
from the indicated grade on the pin on one edge of the roadway to the pin or poured
abutting surface on the other side of the roadway, the depth of grading may be checked to
establish the proper subgrade.
When a mechanical subgrade planer is used to establish the dirt subgrade, a string line
will be placed to control both alignment and elevation. Checking of this will be as
previously discussed. When the dirt subgrade is at the proper elevation, a final rolling of
the surface will be performed with a steel wheel roller weighing no less than 5 ton.
Following this rolling, the final elevation check will be made for approval of the
subgrade. A compaction test may be made to establish that the proper density is present
before pavement or base courses are placed. This final subgrade check, as all previous
checks, should be recorded in the Subgrade Book. A tolerance of ½ inch high will be
allowed in each section checked, provided a trend is no established in the subgrade.
While a roughly compensating section is acceptable, it is desirable to develop as smooth
of a roadway subgrade as possible.
Under no circumstance should a consistently +/- ½ inch subgrade be allowed. A fairly
consistent low soil subgrade may be acceptable, at the contractor’s option, to save time
or assure aggregate base thickness: however, no extra payment will be made for the
additional aggregate base or concrete thickness. Document such areas with extreme
43
Original Date: 1/3/94
Revised Date: 05/27/16
care in both the Subgrade Book and Daily Diary. Base rock moisture and density should
be recorded as well.
(c) Configuration – When superelevation is added to a circular curve, a transition section
must be incorporated into the subgrade. The beginning and end of this section should be
staked by the Survey Party with intermediate stakes showing both grade and rate of
change in transition which should be included in the plans. Aside from alighment and
elevation considerations, these transition sections should present a smooth and consistent
section between the graded check points. The same consideration should be given to the
configuration when sharp vertical curves are present in the roadway. The rule to follow
is “It can be wrong if it looks right, but it can’t be right if it looks wrong.” When making
any adjustments to grade to satisfy the above, special attention to any drainage changes
must be considered.
(d) Density – The standard method of testing density is with a nuclear density gauge. A
minimum of one compaction test should be completed for each day’s work, or, a
minimum of one compaction test per lift per 500 feet of placed fill. To assure uniformity
in rolling, use a random number generator to determine the testing locations (both for
longitudinal location and for lateral offset). Random location testing DOES NOT
prohibit the engineer from testing visibly concerning areas at will. Areas that appear wet
or exhibit excessive displacement should be tested for compliance and remediation, if
necessary.
206.2 DIRT SUBGRADE (ASPHALT)
As with concrete pavement inspection, the inspection of bituminous pavement begins with the
proper preparation of the dirt subgrade. The top 18 inches of subgrade should be thoroughly and
uniformly compacted to a density of not less than 95 percent of the Standard Proctor.
Compaction lifts below the top 18 inches need to achieve 90 percent of the Standard Proctor.
Frequency of testing should follow the guidance established in 206.1 (d). In those areas of
subgrade instability, undergrading should be performed to such a depth as is necessary to provide
a stable base. In isolated areas, the undergraded area may be backfilled with dirt rock or base
asphalt to obtain a stable base. In large areas of instability or saturated subgrade, aeration and
recompaction of the subgrade material may be the best and most economical means of obtaining
stability. Due to the nature of the proposed asphalt pavement, a stable, well compacted base is
indispensable. Before any asphaltic material can be placed, the base must be rolled. Excessive
rolling should be avoided, as it tends to bring moisture to the surface and affects stability. The
elevation and alignment of the roadway will be determined from the offset stakes by use of a
string line and ruler as enumerated in previous sections. Tolerances for grading on the prepared
subgrade will be +/-- ½ inches. The correct elevation of subgrade material must be closely
controlled with checks made at not more than 50 foot intervals, and closer for superelevation
transitions and sharp vertical curves. Results of subgrade checks should be recorded in the
Subgrade Book. The width of the roadway should be the stated lane widths plus an additional
width on each side to produce a side slope of 3:1
44
Original Date: 1/3/94
Revised Date: 05/27/16
207 EXCAVATION FOR BRIDGES
Excavation for structural units is divided into two classifications, Class 1 and Class 2
207.1 CLASS 1 EXCAVATION
Class 1 Excavation will include all excavation within these established limits:
(a) The lower limit of Class 1 Excavation will be an elevation established in the plans. This
elevation will clearly demarcate the lower limit of Class 1 Excavation and will also mark
the upper limit of Class 2 Excavation.
(b) The upper limit of Class 1 Excavation will be the existing ground line or lower limit of
roadway drainage or channel excavation including overbreak, if applicable.
(c) The lateral limit of Class 1 Excavation will establish an area bounded by the perimeter of
the structural unit plus an additional 18 inch width beyond the neat line of the footings,
tie beams or superstructure overhangs. The additional 18 inches width is to allow for
overdigging and working room and should only be included for payment if actually
removed. Where forming of footings or walls is not required and the structural unit is
poured against the walls of the excavation, payment will be made on a computed basis
and will not include any volume beyond the established neat lines of the unit.
Class 1 Excavation will be paid at all structures unless otherwise shown in the Special Provisions
and in the following special conditions:
(a) Class 1 Excavation will be allowed when roadway spill fills are placed and compacted
prior to the construction of intermediate bents (not applicable for abutments).
Measurements will be made from the roadway fill slope to the designated elevation.
(b) Class 1 Excavation will be allowed for columns above pedestal piling. Limits will be the
top of pedestal elevation shown on the plans, the existing ground line or channel
elevation and an 18 inches width greater than the perimeter of the column. No
excavation quantity will be allowed for pedestal pile. Class 1 Excavation will normally
be paid as the volume necessary to reach an elevation as established on the plans as the
fixed plane; however, in some cases an additional depth of excavation will be necessary
to obtain a stable footing condition.
When it becomes necessary to increase the depth of Class 1 Excavation, additional compensation
in pay will be as follows:
(a) Additional depth up to 8 feet below grade equals 125 percent of the Class 1 Excavation
bid price. Additional depth beyond the initial 8 foot overage – by Force Account.
207.2 CLASS 2 EXCAVATION
45
Original Date: 1/3/94
Revised Date: 05/27/16
Class 2 Excavation will include the removal of all material, excluding water, bounded as follows:
(a) The upper limit of Class 2 Excavation will be the elevation designated as the lower limit
of Class 1 Excavation
(b) The lower limit of Class 2 Excavation will be the bottom of footings or seal courses or 18
inches below the bottom of the tie beams and overhands.
(c) The lateral limits of Class 2 Excavation will be the same as for Class 1 Excavation.
As with Class 1 Excavation, additional depth of excavation will involve additional
compensations as follows:
(a) Additional depth beyond bottom of footing up to an added 8 feet of excavation – 150
percent of the contract bid price. Added depth beyond the initial 8 foot extension by
Force Account.
207.3 INSPECTION OF EXCAVATIONS
Inspection of the excavation phase of a structure’s construction will first and foremost be
concerned with the soundness of the underlying supportive material. If not included in the
Special Provisions of the contract, a detailed requirement of the quality of this material will be
available from the Bridge Engineer. (In most cases, a geotechnical report will have been
submitted stating the structural requirements for the underlying strata.) As each structure is
unique in design, these requirements will vary from structure to structure. The Resident
Engineer will be responsible for determining the quality of the underlying material and its
serviceability.
Generally, the following areas of inspection will be observed in most construction procedures:
(a) Regardless of the excavation method used, the contractor will be responsible for removing
the material in a manner which will maintain the stability of the material adjacent to the
excavation. When not specified in the plans, the contractor will be responsible for placing
sheet piling, cribbing or bracing as needed. This requirement should be enforced for each
excavation method, especially when explosives are used. Unless approved by the Bridge
Engineer, excavations by explosives should be stopped at an elevation of at least 1 to 1.5 feet
above the top of footing.
(b) The footing should be placed on undisturbed material free from loose, scaly or disintegrated
rock. When the footing is set on material other than rock, final grade will be obtained just
prior to placing of the concrete for the substructure. If additional excavation is required to
obtain a stable grade due to the contractor’s failure to follow this requirement, no payment
should be made for additional excavation or concrete required.
46
Original Date: 1/3/94
Revised Date: 05/27/16
(c) When the foundation is to be set on piling, the footing area will be excavated to the
approximate final grade before piling is driven. After driving of piling is completed, the final
grade will be obtained by handwork if necessary.
(d) When the footing is to be keyed into the rock, a minimum depth of 6 inches must be obtained
in hard, solid rock and a minimum of not less than 18 inches in soft rock or shale. The keyed
portion will be excavated to the dimensions of the footing with no allowance for overdig.
Quantities for concrete will be computed for neat line dimensions only in this case.
(e) If deemed necessary to aid in the determination of the soundness of the bearing material for
the footin, the Resident Engineer may require the contractor to drill pilot holes at state
intervals and to state depths. The Resident Engineer will then be able to determine the
number and width of seams in the underlying strata by using a feeler wire. Pilot holes will be
paid as a contingent item at a stipulated price that is specified in the contract or the Special
Provisions. The Bridge Engineer or the Geotechnical Report will establish criteria for
acceptable seam thickness of rock below the footing to be tested. The Bridge Engineer
should be consulted before any drilling or testing begins.
(f) When cavities or crevices are encountered in the footing area at grade, the crevices will often
be cleaned and filled with Class B Concrete (as a contingent item at the stipulated price that
is specified in the contract or Special Provisions). In cases of extensive crevice size or
length, the Bridge Engineer may also direct that the crevice be spanned by a reinforced
concrete beam. The Bridge Engineer should always be notified of potential problems
relating to the bearing capacity of the underlying soil or rock.
208 EXCAVATION FOR BOX CULVERT
Inspection of structural excavation for box culvert construction will include all of the above
mentioned elements plus the following:
(a) Undergrading required to stabilize the bottom of the channel below grade will be performed
as directed by the Resident Engineer. Undergrading will normally involve the remval of 1 to
2 feet of unstable material as Class 2 Excavation and backfilling with 2 to 4 inches clean
stone paid at an agreed price per ton. An acceptable alternate is to use a geotechnical fabric
mat in combination with rock backfill. Payment will be included in the Special Provisions as
a Contingent Item; if not, then payment will be made by agreed price.
(b) The contractor will be responsible for pumping water at the excavation site and will be
responsible for providing reasonably dry foundation material for structural development.
(c) When rock is encountered in the subgrade of a portion of the box culvert site, the rock will be
removed for a depth of 6 inches below the bottom of the culver floor. The over excavated
area will be backfilled with material present on site to provide uniform stability.
47
Original Date: 1/3/94
Revised Date: 05/27/16
In all cases where Class 1 or Class 2 Excavations are included in the bid quantities, cross
sections should be taken before construction begins to determine any changes in the existing
ground line, roadway or channel limits.
Since Class 1 and Class 2 Excavation quantities are established within specified limits, any
additional excavation is to be considered unauthorized and a “No Pay” item.
Quantities of excavation should be included as a part of the bridge Book.
SECTION 300
AGGREGATE BASES
301 CONSTRUCTION STAKING
Paving grades will be set on offset stakes determined by the method of paving employed. The
contractor should provide the offset distance required prior to any staking by the Survey Party.
In general, the County will establish pavement grades, radius points, warp grades and flow line
grades for gutters and curb and gutter sections. In all cases, a cut or fill stake will be provided to
determine finished pavement grade or water line grades. “Bluetops” (hubs driven to grade) will
not be provided by the Survey Party. Pavement grades will be established at 50 foot
intermediate (25 foot on horizontal curves) and 100 foot stations.
Upon completion of rough grading by the contractor, area of roadway should be staked to
facilitate fine grading (as explained in Section 200), placing of aggregate base course or asphaltic
concrete bases and paving forms. The contractor should request these areas be staked at least 24
hours prior to the expected work in preparation of the subgrade. The Party Chief should verify
the proposed centerline profile grade and stake the roadway pavements in accordance with these
grades and the typical section applicable as shown in the Construction Plans.
By using the pavement grade stake at the individual offset, a parallel graded string line can be
established. The string line must be set on both sides of the pavement. Care should be taken
when transferring hub grades to the sting line as cut/fill grades will need to be projected to the
string line.
Once this graded string line has been established, the subgrade and base aggregate elevations can
be established at any place by pulling a string line between the existing graded string line and
measuring down the appropriate distance. The subgrade and base elevation should be measured
at the centerline of the roadway, the center of each lane to be constructed and at the outside
edges of the pavement. The difference in elevation due to the cross slope of the pavement must
be taken into consideration when making these measurements.
48
Original Date: 1/3/94
Revised Date: 05/27/16
The final Measurements which are deemed acceptable for the construction of each lift of material
should be recorded in the Subgrade Book.
302 SUBGRADE PLANER
Often the first machine involved in a paving operation is the subgrade planer. This machine is
self-propelled; track mounted and designed to trim the aggregate or dirt subgrade for the paving
operation. As this machine is designed to cut the subgrade, it will be necessary to have the initial
grade higher than the proposed grade. It will also be necessary to make the subgrade wider than
required to allow room for the travel of the slip form equipment. Excess aggregate materials
from the subgrading process may be reused provided proper compactions are obtained. As with
all electronic sensor equipment, the major area of inspection is the contact surface of the
alignment and elevation sensor with the graded string line. If both front and rear sensors are
parallel and in contact with the string line, the grade should be exact and require only
supplemental checks by transverse string line across the grade. Excessive low or high spots will
not be acceptable, and the planer must be backed to regrade such spots.
303 AGGREGATE SUBGRADE
When the dirt subgrade has been properly established and consolidated, the aggregate subgrade
may be placed. Placing of aggregate materials will normally be done by truck and motor grader.
When large loads of aggregate must be driven on the grade for deposition at the point
inaccessible from the shoulder area, rutting may occur in the dirt subgrade. To limit or prevent
this condition the spotter should be instructed to vary the path of the loaded trucks so as not to
concentrate the load to a specific area of the roadbed. Any areas in the dirt subgrade which are
made unusable should be removed and reworked. No payment should be made for this work.
Subgrades and subbases affect the performance of the pavement appreciably, and care must be
taken to ensure that they are adequately designed. Among other reasons, subbases are used
under rigid pavements to control pumping, to control frost action, for drainage, to control highly
compressible soils, to provide a work platform on which to place the concrete slab and to
increase structural capacity. The subbase must be properly compacted so that settlement will not
result. Uniformity of supporting material under a rigid slab is important.
The aggregate surfacing should be of the type designated in the plans and should have sufficient
moisture to allow proper compaction. When material from the quarry is moistened at the
stockpile site or urn through a pugmill to add moisture, a check of moisture content should be
maintained to keep the moisture content at or near the optimum moisture as established by the
Materials Testing Laboratory. Materials which are below optimum moisture will require
extensive compactive effort to obtain the required density as will material well in excess of
optimum moisture. In hot weather conditions, moisture losses to the atmosphere and dirt
subgrade may require addition of more than optimum moisture at the plant site or sprinkling of
the subgrade and aggregate to obtain the required density. Stockpiling of aggregate in piles
rather than spreading immediately may cause unequal drying and a non-uniform product.
49
Original Date: 1/3/94
Revised Date: 05/27/16
Generally, the weather and subgrade conditions will not adversely affect the density results to the
degree that improper handling and compactive effort in establishing the aggregate subgrade will.
Excessive grading will segregate the aggregate and reduce moisture content by aeration.
Improper compactive effort is most often due to ineffective rolling techniques and/or improper
compaction equipment.
Lift thickness should be no more than 6 inches, with the most effective results occurring at 3 to 4
inches. The material, at or near optimum moisture, should be properly spread from the truck be
and then graded to the proper thickness in as short a time as possible with minimum handling.
This type of compactive effort will result in maximum density. When slip form paving methods
are to be used, the width of aggregate subgrade will be increased to provide a 3 foot width
outside the edge of the pavement being placed.
Should segregation of the top of the aggregate base course occur, screenings may be placed by
the contractor to fill the void areas. Compaction tests should not be made in such areas as the
screening will raise the mass of the sample giving a higher result than is representative of the
whole grade; also vibratory rollers have a tendency to bring excess moisture to the surface.
When the aggregate subgrade is graded and compacted, the contractor should notify the RE so
that compaction and thickness of material can be determined. Any areas which fail to have
proper density must be removed or reworked. Prompt notification to the contractor of such areas
is a must. All compaction tests should be recorded in the Subgrade Book with retests so marked
and referenced to the previous failing test. The RE should notify the contractor that penalties
will be assessed for inadequate pavement thickness.
304 FORM PAVING
Upon establishment of the aggregate subgrade, the next procedure involves bringing the
aggregate subgrade to the proper elevation for paving. A one foot width beyond the edge of
pavement is required in order to have a stable compacted base for the side forms. When
conventional form paving is to be utilized, a mechanical form line graded will be used to grade
the aggregate. The form line grader is the predecessor of the subgrade planer used in slip form
construction. The mechanical form line grader is a steel wheeled tractor with offset guidance
system equipped with an adjustable auger to cut grade and a guidance system which will control
alignment and elevation. The tractor must be manually aligned, and corrections in alignment and
elevation are manually controlled. As the aggregate subgrade is cut to grade, the rear wheel of
the form ling grader recompacts the base for the width of the paving form.
305 FIELD MEASURMENT
If the aggregate is paid for by the ton, the material will be paid for using the weight tickets. If
the aggregate is paid for by the square yard, plan quantity will be used except for authorized
changes made during construction. The revisions will be added to, or deleted from, the plan
quantity. Also, when aggregate base is specified by the square yard, the plan thickness of the
aggregate is the minimum thickness required. Thickness of aggregate should be monitored
whether measurement is made by the ton or by the square yard.
50
Original Date: 1/3/94
Revised Date: 05/27/16
Calculating Quantities – It is important for the inspector to know how many tons of aggregate
will be required to cover a given area. This quantity can be computed by using the formula:
FORMULA 305.0 – CALCULATING AGGREGATE APROX. TONNAGE
TONS = L*W*T (M) D
24,000
Where:
L
W
T
M
D
=
=
=
=
=
Length in feet
Width in feet
Compactive thickness in inches
1 + (the percent of moisture in decimals)
Maximum dry density (from the Standard Proctor)
306 CHECK LIST – AGGREGATE BASE
FOUNDATION:
(a) Sufficient density tests on earth subgrade.
(b) Subgrade checked before laying base for conformance with allowable tolerances.
MATERIAL:
(a) Adequate test of moisture content.
(b) Proper moisture content for laying and compaction.
(c) Check that minimum density requirements are met.
(d) Uniform compactive efforts are made.
(e) Proper weight/type roller for conditions.
MISCELLANEOUS:
(a) Have an assistant run the physical tests whenever possible.
(b) Most of the inspection time should be spent observing laying and compacting operations.
(c) Inspect finished section and grade for conformance with acceptable tolerance.
(d) All checks made and test results obtained are to be documented in appropriate inspection
books.
51
Original Date: 1/3/94
Revised Date: 05/27/16
52
Original Date: 1/3/94
Revised Date: 05/27/16
SECTION 400
FLEXIBLE PAVEMENT
401 GENERAL
Asphalt paving equipment is designed to place, consolidate, shape and finish bituminous
products as required by the Specifications. The major difference in paving equipment is the
method of propulsion and the ability to provide the desired final product.
Because of the variety of paving equipment manufacturers and the various modified equipment
in use, this section will deal with general inspection procedures and methods.
402 CONSTRUCTION LAYOUT
Preliminary Items – Prior to the commencement of any paving operation, the Resident Engineer
and contractor’s representative should establish a plan of paving operations in relation to lane
widths, alignment and elevation control. When roadways are from 16 to 24 feet in width, the
paving will be done in one half of the total width. The length will be one day’s paving per lane.
The adjacent lane will be paved the next day to eliminate the vertical drop-off at centerline as
soon as possible. For roadways of greater than 24 foot width, length will be limited to one day’s
production of lanes of equal widths. Under normal construction procedures, full depth main line
paving will consist of several layers of asphaltic concrete base material covered by a wearing
surface; The base asphalt will be installed in lifts of not more than 4 inches nor less than 2 inches
in compacted thickness (A 4-inch compacted thickness will require a loose mat thickness of 41/2 inches). The wearing surface asphalt will be installed in a layer of not more than 2 inches
compacted thickness. Succeeding layers of asphalt will be offset at the longitudinal joint
produced in 6-inch increments, except for the joint in the wearing surface which will be placed
on the lane line when possible. When necessary to control elevation of the finished product, the
Resident Engineer will provide an established grade at centerline. This grade should be provided
at a maximum of 50 foot intervals, or less if in a curve, a sharp parabolic curve or a
superelevation. This grade should be used as an established grade reference by the contractor
when paving commences and should supersede all other grade control methods except on the
wearing surface application. Grade should be set as fills on centerline, preferably converted to
inches for the convenience of the contractor.
(a) Paving Procedure – Paving procedures may vary depending upon field conditions;
however, under most conditions, the same equipment and procedures will apply.
Under normal operating conditions a self-propelled paver, two steel wheel rollers
and a pneumatic roller will be required to place main line pavements and overlays.
In special conditions, which will require prior approval box spreaders, and motor
graders, may be used to place the initial lift of base asphalt. These special areas are
small irregular areas, shoulders, and entrances and side road connections.
53
Original Date: 1/3/94
Revised Date: 05/27/16
402.1 SUBGRADE PREPARATION (OVERLAY)
When existing pavements are to be overlaid, the subgrade preparation will be performed to
provide a sound foundation for the asphaltic concrete. On existing asphaltic and bituminous
pavements, a wedge course may be required to reestablish both the profile and cross slope
grades, or undergrading and base repair may be required to provide a sound, durable base.
Pavement surfacing and texturing is also an often used method performed to reestablish cross
slope and profile pavement grades.
On existing reinforced and non-reinforced concrete pavements and base courses, partial or
complete slab replacement may be required to establish a sound base foundation for asphalt
overlay.
Slab replacement should follow the below stated criteria and may be worked with pavement
repair at joints to produce the required base foundation:
(a) Extensive surface deterioration and erosion which has effectively reduced the slab
thickness or exposed the slab reinforcing fabric to deterioration.
(b) Structural failure in the slab caused by undermining or subgrade failure.
(c) Differential settlement in the slab or between adjacent slabs which has produced a
vertical offset at random cracks or joints.
(d) Moderately heaved slabs which produce a conditions that results in water ponding in
gutterlines or on the slab itself.
(e) Slabs which have major stress cracks resulting from utility access repairs.
These repairs to existing roadway surfaces will normally require lane closures and special
materials.
403 PAVING FABRICS
Many overlay contracts specify the use of paving fabrics in the contract. This is the placement of
a layer of fabric between the new lift of bituminous concrete and the existing pavement.
403.1 SURFACE PREPARATION
The paving surface must be prepared in the same manner as it would be for an overlay (roadway
swept and dry, gutterline free of leaves, dirt, and other debris).
54
Original Date: 1/3/94
Revised Date: 05/27/16
Tack will be placed on the existing surface immediately in advance of the fabric placement
operation. Since different paving fabrics have asphalt retention properties that vary, the
application rate of tack coat should be specified by the fabric supplier.
403.2 FABRIC PLACEMENT
A tractor with a special adaptor can easily place a 12 foot width of fabric in advance of the
paving operation. Fabric placement moves quickly and, normally, does not impede the paving
operation. Since the work progresses rapidly, the inspection effort must not wane. Adjacent
layers of fabric must be overlapped by 6 inches. Air pockets between the fabric and underlying
pavement or creases and wrinkles in the textile must be eliminated before the fabric is overlaid.
The in-place fabric will occasionally tear under stress from construction traffic. When this
occurs, the damaged section must be patched with a minimum 6-inch overlap.
Your Regional Project Engineer Supervisor, the fabric manufacturer’s representative, or the
Materials Engineer can be consulted to address concerns which may arise due to special field
conditions.
404 EQUIPMENT
404.1 DISTRIBUTOR SYSTEMS
The most common distributer system in use for main line paving operations is the truck mounted,
self-contained, pressurized distributer. This system utilizes a pressure pump which is operated by
a PTO gearing capable of both circulating the onboard asphaltic material and providing the liquid
asphalt material to the spray bar or hand spray at sufficient pressure to ensure a uniform spray of
material onto the surface to be paved. The circulation system is used to evenly heat the asphaltic
material to a temperature which will allow for distribution at the most uniform rate.
This temperature is normally around 130° F for emulsified asphalt tack, 260° F to 325° F for
asphalt cements and from 70° F to 180° F for liquid asphalt prime. The major safety
consideration when heating these materials is overheating. Care should always be taken to
operate at temperatures below the flash point. The heating system is controlled by a propane
heating system located at the rear of the truck. By circulating the asphaltic liquid around heating
tubes, the material may be heated and maintained near a specific temperature. A thermometer
mounted on the driver’s side of most trucks in the center of the storage tank is used to monitor
the temperature of the heated liquid.
The spray distribution system varies by manufacturer but generally is composed of a rear
mounted spray bar which is equipped with a series of nozzles so that an application of material
can be precisely placed in widths from 1 foot to 14 feet and in 1 inch increments. The nozzles
area attached to the spray bar so as to be at a constant height above the pavement surface which
will produce an overlapping triple fan spray. The nozzles should be set to 15 to 30 degrees from
horizontal. Each nozzle is capable of independent combined operation by an on-off linkage
55
Original Date: 1/3/94
Revised Date: 05/27/16
which is controlled from the vehicle cab by the driver and is set by joining or releasing the
nozzle linkages. Additional lengths of spray bar may be added for extended width of application.
Overlapping or “double shooting” to achieve extended width of application should not be
allowed. The amount of tack being placed is controlled by a Bitumeter System (gallons per
square yard) which discharges the asphaltic material at a uniform rate through a calibrated
system regulated from the vehicle cab and calibrated by using a measuring wheel mounted under
the truck frame, usually directly behind the driver’s door. Because of the subjective nature of
application, a wide range of application rates is allowed by the Specifications. The truck should
also be equipped with a hand spray wand for areas that cannot be done with the truck spray bar.
The volume of material available in the truck-mounted tank can be determined by dipstick and
conversion table or by a direct reading dial gauge mounted on the rear of the tank. In either case,
a level parking area must be marked out so that initial and final daily readings may be taken.
Areas of inspection for tack and prime coat placing should include the following:
(a) Proper heating of the specified material together with initial volume reading in the tank.
(b) Proper operation of the individual spray bar nozzles as to width (one foot wider than
asphalt mat being placed), cut off and proper linkage connections on the spray bar and
overlapping of the fan spray from all nozzles.
(c) Maintenance of the 600 foot maximum distance of prepared surface in advance of the
paver with consideration given to traffic congestion and traffic flow in major
intersections.
(d) Straight application of the asphaltic material within the area to be paved so as not to
infringe in designated travel areas or to overspray the curb or sidewalk. Note that in some
cases it may be necessary to apply liquid asphalt products in the curbline at a slower than
normal rate or with only the outside end of the spray bar being utilized. To avoid
puddling or overspraying of material and to maintain proper PTO operation, a lower
gearing, hand spray or, in some cases, gravity feed of asphaltic material may be necessary
to produce the required results.
(e) Wind direction and velocity should also be considered especially when placing prime
coats, as the material in a fine mist may be carried for some distance from the application
site.
(f) Uniform application of tack or prime coats should prohibit stringing, puddling, uncovered
areas, overspray, and double shooting on the prepared surface. The application rate of
asphaltic material must be rigidly tailored to the prevailing field conditions and must be
varied as roadway surface conditions change. Maintenance conditions such as bleeding,
mat slippage and washboarding are the result of too much tack or prime, as delamination
of paved surface is the result of too little tack or prime.
56
Original Date: 1/3/94
Revised Date: 05/27/16
404.2 HAULING EQUIPMENT
Trucks used to haul bituminous materials must be equipped as follows:
(a) The bed of trucks used to haul asphalt must be clean, smooth, free of holes, made of metal
treated with an approved material to prevent adhering of asphalt, and equipped with a
will fitting tailgate and tailgate lip and insulated, if necessary to maintain the proposed
heat range. Trucks should be clearly numbered and free of any hydraulic leaks.
(b) The truck must be equipped with a covering for the entire bed. The covering must be
retractable and must be in place while the load is in transit and until placed in the paver
hopper.
(c) The truck must obey all load restrictions. Working on a County project does not
circumvent the law. Currently, the St. Louis County area is controlled by truck weight
restrictions established for the interstate highway system, the commercial zone (often
called heavy haul zone) and the posted bridge gross weight system. The interstate
highway system imposes a maximum gross weight limit of 40,000 pounds. The
commercial zone, comprised of most other routes, is limited to 22,400 pounds/axle
maximum. The county posted bridge gross weight system specifies total gross vehicular
height allowable per structure.
404.3 ROLLERS
Rollers used in connection with asphalt paving operations are of three types – steel wheel,
pneumatic and vibratory. All rollers are to be self-propelled, capable of reversing directions
without backlash, and have a water system which will moisten the roller or wheels. Steel wheel
rollers are the most common type of roller and are commonly used for both asphaltic pavement
and seal coat applications; however, rubber tired rollers are preferred on seal coat applications.
Rolling speed should not exceed 3 mph.
(a) The steel wheel roller normally comes in 1, 5, and 10 ton sizes and is used for both initial
and final rolling. Generally, the steel wheel roller will have a larger diameter drive
wheel and a smaller split drum or dual drum steering wheel. The roller is equipped with
a dual control directional system, a ballast system which doubles as a water reservoir for
the roller moistening system, a scraper located on each roller to keep each roller clean
and, in most cases, a scrubber composed of jute fiber on each roller for the purpose of
cleaning the roller.
Inspection of the steel wheel roller will include the following:
(1) The water reservoir should be full and filled as necessary during the paving
process.
57
Original Date: 1/3/94
Revised Date: 05/27/16
(2) All connecting hoses, pumps and spray bars used to moisten the roller should be
checked for blockage to ensure a free flow of water to the rollers.
(3) The scrapers and scrubbers should be free of built-up debris and mud. They
should be in full contact with the roller and should be cleaned periodically.
(4) The face of the rollers should be checked for cuts or severe pitting which would
adversely affect the surface smoothness off the pavement.
The pneumatic roller is to be self-propelled, oscillating type (wobble wheel) and
equipped with smooth tires of equal size, diameter, ply rating and inflation pressure. The
roller is also equipped with a water reservoir-ballast system which is designed to moisten
each wheel and a scrubber mounted to clean each wheel.
Inspection of the pneumatic roller will include the following:
(1) The water moistening system should be thoroughly checked to ensure proper
orientation for each wheel. The scrubber should be checked for full contact with
the wheel and should be cleaned periodically.
(2) Each wheel must be checked for equalized air pressure and bearing on the
roadway surface. A minimum of 80 psi contact pressure must be maintained for
each wheel. The contact pressure will depend on the tire size, tire air pressure,
and operating weight of the roller. The contractor must be able to confirm that
the required contact pressure is being developed.
(3) The bearing face of each wheel should be checked for smoothness and should be
free from cuts, breaks in the surface and major surface pitting.
The vibratory roller is a self-propelled steel wheel roller with an added vibratory system.
Under normal conditions, the vibratory roller is not allowed as a roller for asphalt
paving operations (such as thin overlays).
When, by special permission, the vibratory roller is used, the following items should be
inspected:
(1) All areas of inspection enumerated for the steel wheel roller should be observed
for the vibratory roller.
(2) The vibratory system should be in good operating order. The degree of intensity
of vibration should be monitored to prevent a “wave” condition from appearing
in the asphalt. Vibration frequency should be between 2,000 to 3,000 vibrations
per minute. The roller should be equipped with an automatic cut off for vibration
when the roller stops moving.
404.4 BOX SPREADER
58
Original Date: 1/3/94
Revised Date: 05/27/16
The box spreader is a non-propelled asphalt paver of limited usage. The box spreader is used
primarily for entrances, parking areas, shoulder areas, and areas of limited width (8 feet or less).
The box spreader is propelled by attachment to the hauling equipment which supplies the
asphaltic material. The box spreader is equipped with a hydraulic system which closes the
hopper gate, locks the tow attachment to the wheels of the dump truck, raises the screed and, on
some models, extends and retracts the strike-off extenders. Some models have a device to allow
a crown to be placed in the screed.
Inspection of the box spreader includes the following:
(a) The screed and strike off on a box spreader are supported on four pneumatic tires. The
air pressure in these tires should be checked and equalized.
(b) The edge plate on the strike-off extenders and the hopper gate should completely shut off
the passage of asphaltic material when closed. Extra material on the pavement surface
should be removed before rolling operations commence.
(c) The screed should be checked by a string line before any asphalt placing commences.
Parabolic crown may be added to the screed once a true plane is obtained.
(d) The hydraulic system should be checked for leakage and should be fully operational
before any paving commences.
(e) On box spreaders equipped with a screed heating device, all lines should be checked for
leakage and for even heat distribution on the screed.
(f) The tow attachments should be checked on each hookup to ensure an even pull on the box
spreader.
404.5 ASPHALT PAVER
The asphalt paver is generally manufactured by Cedarapids, Blawknox and Barber-Greene
Corporations. These pavers vary somewhat in attachments, electronics, and the method of
asphalt placement; however, the basic mechanisms are comparable, and inspection of each
machine will be similar. Bituminous pavers are self-propelled units, either track mounted or
mounted on pneumatic tires and equipped with dual controls for the operation of all individual
systems. The controls are affixed to an operating platform mounted to a carriage equipped with a
hopper and distribution system, a fully activated screed or strike-off assembly, a screed heating
system, a vibration system and a system of automatic screed and cross slope controls.
Inspection of the paver and various component systems should include:
(a) The carriage and operating platform are equipped with an engine and various hydraulic
systems – these elements should be checked for leakage of petroleum based liquids. On
59
Original Date: 1/3/94
Revised Date: 05/27/16
some models, the carriage is equipped with a tow attachment similar to a box spreader
which engages the rear wheels of the dump truck. When this tow attachment is in
operation, a check should be made for a proper hookup and even pull on the paver. When
non-track mounted pavers are in use, the pneumatic pressure of all tire should be
checked for compliance with manufacturer’s recommendations.
(b) The hopper should be of such a capacity as to allow for a uniform spreading operation
and should be equipped with a hydraulic lift on each side of the hopper which will allow
for the dumping of all asphaltic material into the conveyor system for distributing with
minimal heat loss. The conveyor system is composed of two independent conveyors and
augers which are designed to move the asphaltic material from the hopper to the front
edge of the strike off or screed with as little segregation as possible. The augers are
mounted so as to allow for the movement of the asphaltic material left or right to the end
of the strike-off extender when fully extended. A pendulum-type sensor or infrared sensor
is mounted to the carriage frame at the end of the conveyor and automatically controls
the speed of the auger, thereby controlling the asphalt volume in front of the strike off.
On many machines, a manual override is present for use when the strike off is at
maximum extension.
(c) The strike-off assembly or screed is mounted to the carriage by two hydraulically
controlled arms and is otherwise independent of the rest of the paver. The screed is
further independent within this assembly, being adjustable in elevation by a screw gear
apparatus on each side of the screed. The screed is also adjustable and should be
checked for straightness before use. A crown section can also be placed in the screed by
measuring offset distances from the string line to the screed. The hydraulic lift on the
strike-off assembly should be checked periodically for leakage as the ability of the
machine to carry a grade will depend on the integrity of the system. The elevation control
on the screed should be well greased and free to turn. The elevation control should be
centered whenever the strike-off extenders are hydraulically operated and usually have a
manual control mounted to the outside of the operating platform, usually at the rear of
the platform. They should be checked periodically for hydraulic fluid leakage.
(d) The screed heating system and vibration systems are designed to enhance the finishing
ability of the screed.
The screed is heated by two diesel fuel burners mounted within the screed. Most pavers have
internal lighting mechanisms, and the amount of heat is controlled by dampers and blowers
mounted in or on the screed. The burning and lighting mechanism must be in proper working
order and must be controllable to prevent warping of the screed or possible explosion. The
vibration system is composed of internal pan vibrators or a tamping bar system. The frequency
of impulse of the vibrator is usually controllable, and a manual rheostatic control is often
mounted on the back of the operating platform. The tamping bars should be set to between 1/64
inch below to 1/8 inch above the screed plate.
404.6 AUTOMATIC SCREED CONTROL
60
Original Date: 1/3/94
Revised Date: 05/27/16
The automatic screed control is designed to control the cross slope of the pavement and maintain
the elevation of the screed thereby producing a uniform surface of required typical section. The
automatic controls are equipped with a manual override which will allow the operator to adjust
or vary the slope for superelevated curves. There are three types of automatic screed controls.
(a) The first type of automatic screed control utilizes a sensor which follows an established
grade referenced or string line for alignment and elevation control. The string line sensor
is applicable for use in placing the first two layers of asphaltic material or for placing
overlays. Inspection procedures for paving with string line sensor are included in Section
500, Rigid Pavement, -502 – Slip Form Paving.
(b) The second type of automatic screed control utilize a sensor which mounts to the carriage
of the paver and utilizes a shoe-type indicator to ride on top of an adjacent surface. The
shoe travels on the adjacent surface the sensor establishes the grade control by
reproducing the existing surface. This type of sensor is applicable for use only when the
initial lift in overlays or leveling courses has been made but must be closely monitored
for accurate reproduction of the desired surface.
(c) The final type of automatic screed control is referred to as a “traveling reference” or ski
pole. The ski pole must be a minimum of 30 feet in length, is usually composed of
aluminum and is attached to the carriage of the paver in such a manner as to run parallel
with the paver on an adjacent surface. The ski pole is designed to reproduce an adjacent
surface similar to the shoe-type sensor but, because of its length, remove abrupt changes
in grade or elevation. The “traveling reference” is applicable for placing asphalt in all
lifts except for the finish surface of full depth asphalt roadways.
Inspection of these automatic screed controls is mainly confined to checks for fully functioning
electrical components, straight control or sensor arms and sound connections to the paving
carriage. On older model pavers, the ski pole should be checked visually for straightness. Older
model ski pole assemblies are also supported by a monofilament string framework which is
subject to breakage with use.
405 MATERIALS
405.1 PRIME AND TACK COATS
Prior to the application of any asphaltic concrete pavement, the prepared subgrade will, in many
cases, be prime coated or tack coated. In general, prime coats which consist of MC-30 Liquid
Asphalt or tack coats which consist of SS1-H or Emulsified Asphalts will be used. Normally,
County policy is to use prime coats on rock surfaces and emulsion tack coats on existing
concrete or asphalt surfaces. Specific types and grades of material will be specified in the Special
Provisions. The contractor shall provide sand of the proper type to be used as a blotter in traffic
situation when required by the Resident Engineer. Payment for the use of blotter sand is usually
specified in the Special Provisions.
61
Original Date: 1/3/94
Revised Date: 05/27/16
Because of the temperature range in which emulsion and liquid asphalt may be placed, pay
quantities will be subject to a correction factor for volumetric expansion. The measurement will
be based on a volume at 60° F and in an undiluted state (for emulsions).
For liquid asphalts the correction factor will be:
FORMULA 405.1 – LIQUID ASPHALT CORRECTION FACTOR
Volume @ 60° F = Weight in pounds of Material
Specific Gravity @ 60° F x 8.328
For emulsified asphalts the correction factor will be:
0.0003 gallons/degree F above or below 60° F
Both correction factors should be applied to the observed volume used and rounded to the
nearest 10 gallons for payment.
On site material testing of asphaltic materials will be limited to obtaining liquid products before
application and visual inspection of each load of asphaltic material. An accurate temperature
check of the delivered materials should also be made.
405.2 ASPHALT
Asphaltic concrete paving products will normally be labeled as Type X bituminous base for
foundation or base courses and as Type C asphalt concrete or bituminous concrete for wedge and
wearing courses. Type D asphalt will normally be considered as a drive approach wearing course
to be placed by handwork methods. Special skid resistant asphalt wearing courses are produced
by utilizing porphyry or slag components to augment the normal limestone aggregates. In all
cases, these asphaltic paving products will be produced in accordance with a design mix
prepared by the supplier and approved by the Materials Testing Engineer. Inspection of asphaltic
paving products will be under the direction of the Materials Testing Laboratory personnel. The
signature of the plant inspector will verify compliance with the design mixture in the production
of asphaltic products.
Visual inspection of asphaltic products will include verification of asphalt type and checking for
aggregate segregation, uncoated aggregate or material with a burnt appearance for each load
accepted in the field. Field verification of temperature compliance in the production of the
asphaltic paving products is of paramount concern and must be closely monitored as compaction
compliance is directly controlled by temperature. The asphaltic product temperature should be
monitored in the paver hopper and immediately behind the paver screed with changes made by
the Resident Engineer as required.
62
Original Date: 1/3/94
Revised Date: 05/27/16
Asphalt temperature for base courses and wearing courses should not exceed 350° F at point of
origin and must be within a temperature range tolerance of +25° F of the temperature designated
by the Resident Engineer. Current design mixes for wearing courses require a hopper heat of
325° F (+25° F) and a behind the screed heat of 300° F minimum for compaction; however, these
requirements will vary from mix to mix. Base mixes require a minimum heat of 250° F. A copy
of the mix design which notes the proper compacting temperature of the bituminous material can
be obtained at the Materials Testing Laboratory.
406 ON-SITE INSPECTION PROCEDURES (ASSOCIATED ITEMS)
406.1 PERSONNEL
The actual paving operation should be inspected in the following manner:
(a) Personnel – Main line paving and overlay will require a minimum of three inspection
personnel. The least experienced inspector should be assigned to duties in advance of the
paver. These duties should include control of tack coat in advance of the paver,
arrangement of dump trucks for discharge at the paver, advance traffic control,
temperature check, preliminary material inspection and collection of material delivery
tickets. An experienced inspector should be assigned to duties behind the paver. These
duties should include control of the rolling process, supervision of handwork in
connection with seams and interruptions and opening of cooled pavement to traffic as the
paving proceeds. The most experienced construction personnel should be assigned to
inspection duties at the paver. The duties include supervision of the paving crew, check
the operation of the paving equipment, control of lift thickness, lane width and all
components of the placing operation.
By properly placing these personnel, the Resident Engineer will be free to oversee the entire
operation and, in particular, control compaction, safety, and traffic control operations.
406.2 TEMPERATURE RESTRICTIONS
The placing of asphaltic pavement and overlays will in large part be controlled by weather
conditions. Temperature restrictions in paving will, in general, be governed by the ambient
and/or surface temperature. All asphalt courses, except the wearing course, may be placed when
the ambient temperature is above 40° F. Wearing courses require an ambient and surface
temperature of at least 50° F. See Special Provisions for each project.
Asphaltic material may not be placed on a wet or frozen surface or when weather conditions
would prevent the proper handling of the material.
These guidelines are designated to provide adequate elapsed time for the rolling of the surface to
obtain compaction vs. rate of cooling. Other factors which are not specifically enumerated here
are wind direction and wind velocity. All of these factors will affect the rate of cooling and the
63
Original Date: 1/3/94
Revised Date: 05/27/16
time available for handling. Careful consideration should be given to all of these factors during
marginal paving periods.
406.3 MATERIAL SUPPLIERS (24-HOUR NOTICE)
All materials used on the project must be inspected either at the point of origin or on the project
site before inclusion into the project. Normally, products produced locally and on a daily basis
will be inspected by Materials Testing Laboratory personnel. Other products may be inspected
by professional testing facilities and certified as meeting St. Louis County requirements or by
field personnel on site.
When testing is to be performed by Materials Testing Laboratory personnel, a 24-hour notice
from the contractor will be required. When testing is performed by other facilities, a certification
and testing results should accompany the material.
Material shipped to the project is subject to all pertinent laws and wright restrictions. Truck
routes must be based on compliance with established weight limits.
406.4 TEMPORARY STRIPING
Tack coat and asphalt overlay techniques will in large part eliminate or render ineffective the
existing pavement and striping and pavement markings on the project. During asphalt placing
operations, traffic control is maintained by arrow panels, cones, channelizes, and signing;
however, as the paving operations proceeds, temporary striping should be placed to (1) limit the
distance closed to traffic and (2) provide a non-obstructive traffic control method until
permanent pavement striping and markings are restored.
Temporary striping in the form of a 4-inch wide adhesive backed tape of white or yellow color
impregnated with reflective material should be placed on a daily basis in 4 foot strips at
approximately 40 foot intervals for all pavement placed that day. This temporary tape may be
replaced by standard paint striping for areas of pavement which have been surfaced and textured,
wedged with asphalt or left in an uncompleted form (due to weather) for two weeks after
completion.
Because of the volume of traffic on most County roadways, particular attention to left turn lanes,
right turn lanes, cross walks for pedestrians and similar intersection markings should be noted
and, if possible, duplicated on a temporary basis to avoid congestion and inconvenience. Any
question on proper utilization or placement of striping or pavement markings should be clarified
by a member of the Traffic Division. In general, temporary striping will be a lump sum or lineal
foot item or included in the cost of other items.
406.5 LOOP DETECTORS
Loop detectors are electrical wires placed in or under the pavement surface which, when
energized, produce an electrical field and actuate when interrupted by a metallic object such as
64
Original Date: 1/3/94
Revised Date: 05/27/16
an automobile or motorcycle. This will signal the intersection controller and allow for traffic
movement through the intersection. Loop detectors are in use for fully actuated intersection or
for side street actuated intersection and are not present in pre-timed controller intersections. Loop
detectors may be square or rectangular in shape and may or may not be visible in the surface of
the roadway as the loop detectors work equally well exposed or under a 2 inch asphalt overlay.
The location of loop detectors should be stated in the plans and must be verified with the Traffic
Division.
The contractor is required to give 2 days’ advance notice when these loop detectors are to be
taken out of service, and service should be restored within 5 days if possible. This requires a
coordination of pavement surfacing and asphalt overlay operations which must be overseen by
the Resident Engineer in accordance with the various subcontractors, prime contractor, and
Traffic Division representatives. Clean outs, which are brass capped cylindrical wire splice
junction boxes, should be located and marked to prevent destruction during pavement surfacing
operations or lost during overlay operations.
Installation of loop detectors will be overseen by personnel of the Traffic Division who will lay
out and inspect the installation. Work force, equipment, and material quantities will be provided
by the Traffic Division personnel on a daily basis and, generally, will vary from the quantities
anticipated by the plans due to relocation and resizing of the loop detectors.
406.6 UTILITY ADJUSTMENTS
Utility adjustments will occur on virtually every County roadway. Normally, the utility
companies will work in close association with the contractors and County forces during overlay
operations to adjust their facilities to grade of the new roadway. The County’s Utility
Coordinator will provide information to the utility companies at the Pre-Construction Meeting
and afterward concerning scheduling and adjustment needs. The Resident Engineer should keep
the Utility Coordinator abreast of ongoing operations and adjustment needs.
Under normal conditions, the following procedures are observed by the various utility
companies:
St. Louis County Water Co. – Valve adjustments are made by cast iron riser as paving operation
occurs. All valves are located and adjusted by water company personnel.
Laclede Gas Co. – All valves and gas drip boxes are located and marked by gas company
personnel and may be adjusted during or after overlay procedures.
Southwestern Bell Telephone – Manhole entrances to vaults are adjusted individually by brick
and mortar by subcontractor or by adjustment ring provided by utility and installed by the utility
company’s personnel or by paving contractor personnel.
Union Electric – Underground vault manhole entrances are adjusted by rider ring provided by the
utility company and placed by utility or paving contractor personnel.
65
Original Date: 1/3/94
Revised Date: 05/27/16
As a matter of course, the utility companies maintain a large number of adjustment risers of
various height. Most risers come in ¼ inch increments of height, and it is good practice to have a
variety of heights available on the project. As a matter of practice, the roadway grade of asphaltic
material being placed should not be altered to match a utility facility – the utility should be
adjusted to match the new asphalt overlay grade.
406.7 MANHOLE ADJUSTMENT RINGS
Manholes within the right-of-way are generally a part of the Metropolitan Sewer District (MSD)
system of sanitary, combined or storm sewers. AS MSD is a quasi-governmental agency,
adjustment of their facilities is a pay item in St. Louis County contracts and is subject to MSD
standard requirements and inspections.
Adjustments of these facilities to new asphalt grade may be accomplished by using brick and
mortar or by using and adjustment riser ring. Regardless of method to be employed, prior to the
paving operation, each manhole lid should be marked with paint and paint mark placed on the
curb or shoulder with distance to the lid. This will allow reestablishment of the manhole after the
paver passes.
Adjustment riser rings are both adjustable in height and expandable in diameter; they are to be of
grey or ductile iron coated with black vinyl plastisol gasket for noise reduction and in 4 equally
sized segments.
The following two types of manhole risers are approved for use by MSD:
(a) A 4 segmented base ring held together by 4 stud bolts with a U-shaped configuration into
which a 4 piece backplate may be adjusted in 3/8 inch increments. Elevation is controlled
not only be the elevation placement of the backplate segments in the baseplate but also by
the thickness of the baseplate itself. Cross slope is not readily adjustable using this
device.
(b) A 4 segmented combination base/backplate unit held together by 4 stud bolts and
vertically adjustable by a bolt in the baseplate of each segment. Because of the individual
elevation bolts, and infinite number of height settings may be easily obtained as may
varied cross slopes. This is the preferred adjustment riser; however, because of the
lighter weight material, care must be taken not to bend the back plate.
Generally, installation of the manhole adjustment riser ring should be made after the paver has
placed the asphalt mat and prior to the initial rolling. Installation in advance of the paver can
produce bumps in the mat as rapid adjustment in the mat thickness to clear the riser may be
necessary. The possibility of the screed striking the riser and pulling the riser from the manhole
frame and filling the manhole with hot asphalt should preclude this method of adjustment.
Installation following the paver also ensures the maintenance of the new roadway asphalt grade
and accurate height adjustment of the riser prior to placing in final position. It should be noted
66
Original Date: 1/3/94
Revised Date: 05/27/16
that it is absolutely necessary for the asphalt mat to be even or slightly above the adjustment riser
to avoid being struck by snow plows.
The riser stud bolts should be adjusted in order to expand the adjustment riser to obtain a firm fit
in the existing manhole frame. It is very important to obtain a snug fit as too loose or too tight fit
can cause the adjustment riser to pop off the frame. It is very important to expand the base
segments evenly to avoid an oval or warped shape which may break or pop out under traffic.
Also important for stability is a lid of proper thickness and configuration. Proper thickness may
be obtained by substituting lids or by placing a rubberized bituminous rope gasket under the
existing lid. It should be noted that lock down type lids are no longer required by MSD
standards, and as a special thin-walled socket is required to open the lock down device, they
should not be replaced unless specified.
MSD also requires that not more than 2 adjustment risers be stacked above the original manhole
frame. Should this condition occur, it will be necessary to remove the existing adjustment rings
and install taller adjustment risers or to adjust the manhole frame by brick and mortar methods.
406.8 DRIVEWAYS AND STREET INTERSECTIONS
Driveway and street intersections must be placed integrally with the main line asphaltic
pavement. The purpose of placing a hot joint at these locations is to stop subsequent cracking,
water infiltration and spalling at the joint interface between successive lanes of asphalt paving.
Under normal conditions, this hot joint will be at the flow line of the roadway and is therefore
more susceptible to water related damage. As driveway asphaltic material is of a finer graduation
than main line material (Type D vs. Type C), the contractor must provide a crew in advance of
the main line crew to install these driveways so that a hot joint may be obtained. This driveway
crew’s progress must be monitored so as to stay in advance of the main line crew without getting
too far in front of the main line crew and voiding the hot joint by excessive cooling. The water
line area will be a grade adjustment area where the main line overlay edge grade will intercept
the driveway overlay grade. Under no circumstance should the main line edge grade be adjusted
to match a driveway grade; to do so is to produce a dip or bump in the roadway mat and to alter
the pavement edge flow line which could trap water. This grade adjustment can best be
accomplished when both driveway and main line asphalt have sufficient heat.
Compaction of driveway asphaltic material is usually obtained by using a 1 or 2 ton steel wheel
roller which is very maneuverable due to its reduced size. A hand tamper may be necessary to
remove roller marks around radii and other confined areas. Rolling should be continued until all
roller marks are removed.
Street intersections should be placed at the same time the main line roadway mat is placed and
should be roller with the main line mat to avoid tearing, shoving and separation of the joint at the
water line. There are a wide variety of ways to perform this operation and, because of traffic
control within the intersection, no particular method should be considered the only way.
Generally, however, the asphalt hauling trucks should be kept on the main line or ahead of the
67
Original Date: 1/3/94
Revised Date: 05/27/16
paver. The paver is vastly more maneuverable than the truck and should go to the truck when the
hopper is empty. Paving should commence at a radii and proceed to the other side of the side
street. When possible, it is best to pave away from the side street butt joint to produce a good
grade adjustment at the water line and to avoid excessive handwork at the butt joint which
produces bumps. It is important to set back on the main line mat behind where the paver picked
up or intercepted the side street grade to reestablish the main line grade and remove the bump
invariably produced when the paver stops.
In large intersections, where traffic control will be a major consideration, it may be necessary to
pave and open the side street in halves. Traffic control is best maintained by flaggers. Production
in the paving process will be reduced as a large amount of handwork and traffic control will take
a great deal of time.
406.9 SIGNING
Signing is the first indication of road construction ahead that the motorist will have before
entering the project, and signing will successfully and safely guide the motorist through the
project with a minimum of inconvenience and time delay. Signing should be concise, accurate
and not too complex to be easily understood and followed.
Advance construction signing is normally placed by St. Louis County Traffic Division personnel
at the request of the Resident Engineer. Signing on multiple projects should not be placed until
construction is ready to proceed and should be removed only when all work on the project is
completed. Normally, advance signing will consist of “Road Construction Ahead” and will be
black letters on an orange background.
All advisory or regulatory signing is to be provided and placed by the contractor. This signing
should be erected either permanently and covered when not in use, or be on portable supports
which, when erected and sandbagged will remain upright during the course of the work.
One major problem in signing a project is not the availability of signing or information being
conveyed but a flood of information placed on closely spaced signs which is undecipherable to
the motorist. Signing should be placed well in advance of the start of construction (500 to 1,000
feet) and at intervals which allow motorists to comprehend the instruction being presented (200
to 300 feet intervals). Standard recommended spacing for signs and signs to be placed under
common construction conditions is generally included in the details of the Construction Plans or
on the Traffic Control Plan when detours and road closures are included in the project. All
construction signs are black letters on an orange background.
For convenience, certain advisory signs are almost always grouped together to conduct traffic
through a construction zone. On two lane pavements, “Road Work Ahead” or “Road
Construction Ahead” should be followed by “One Lane Road Ahead” and finally “Flagman
Ahead”; on 4 lane pavements, “Road Work Ahead” or “Road Construction Ahead” should be
followed by “Left (or Right) Lane Closed Ahead”; on multiple lanes or continuous turn lane
pavements, the lane closed ahead sign contains information to show multiple lane closure or
68
Original Date: 1/3/94
Revised Date: 05/27/16
center lane closure; on pavements which have been surfaced and/or textured, “Rough Grooved
Pavement” and “Uneven Pavement” signs are required.
Other frequently used signs are “Bridge Work Ahead,” “Bump,” “Fresh Oil,” arrows for
direction guidance and regulatory speed limit signs. (Note: Speed limits can only be changed by
County Council action – regulation is handled by local police).
Probably the most important sign on any project is the handheld “Stop-Slow” sign used by the
flagger. This sign cannot be used too much and should always be present and in use when traffic
is slowed or stopped for any reason. When the frequent use of the handheld “Stop-Slow” sign is
anticipated, the “Flagger Ahead” sign should be posted to help protect the flagger.
“No Parking” signs are frequently used on asphalt overlay projects but are not enforceable unless
posted the day before expected use with approval of the governing police organization. The signs
should also be removed when paving is completed or suspended.
406.10 MISCELLANEOUS
(a) Night paving – As a general rule, the contractor may request to perform asphalt paving
for overlays during non-peak evening and night hours. By so doing, the contractor can
increase his available time to place asphalt, decrease inconvenience to the general public
and have complete access to his production facilities. Negative aspects of night paving
are an increased chance of accidents and personal injury to the working and inspection
forces, noise ordinance violations (late at night), confusion of motorists in the work area
and increased difficulty in inspecting the mat.
Inspection of night paving requires a higher degree of intensity than needed in daylight
hours due to the limited time available for inspection and the limited amount of light and
lighted distance that can be observed. Proper inspection entails more than adequate safety
precautions. Cones must have reflective tape attached, must be clean and of proper height
and must be placed at the proper distance interval or closer. Arrow panels must be used,
and all lights must be operational. In addition, all signs and tapers must be properly
placed. All personnel must be equipped with reflective safety vests and reflective signing
must be used for flagging operations. Trucks on the project should use all hazard lights
possible, including curb mounted, high intensity, safety and directional light bars, and
flashers. The paver and all rollers must have adequate lighting to provide for safety and
illumination to perform the proper placing and compaction of the asphaltic mat. Auxiliary
portable overhead lighting should be required and utilized when possible. Local police,
when possible, should be requested to help control and direct vehicle traffic.
Inspection of the actual pavement overlay operation will vary little from normal daylight
operations. Placing speed of the paver must be monitored as the increased supply of
asphaltic material to the paver may cause an overall speedup of the placing in excess of
the speed at which the rollers may obtain compaction. Wedging and use of the automatic
screed controls should be confined to daylight hours when possible. At night, placing
69
Original Date: 1/3/94
Revised Date: 05/27/16
should be controlled by thickness being placed or established grade reference. Handwork
and rolling will require very close inspection as shadows will make the determination of
the quality of the work performed very difficult. Many of the areas which are reworked at
night are made to appear unacceptable by shadows and insufficient light. For this reason,
the roller operators should be stopped and the area illuminated to obtain a clear picture of
the area in question. Handwork at butt joints and transverse construction joints should be
closely monitored to avoid irregular pavement at these locations.
(b) Additional paving accessories – On older model pavers, the screed is fixed at 10 feet in
length. In order to pave wider widths and maintain the quality of the asphalt mat being
placed, a screed extension is required. Screed extensions come in 1 and 2 foot segments
and bot directly to the main screed of the paver within the flow control gates. These
extension segments provide for continuous vibration, heating and surface elevation of the
screed for extended paving widths. The contactor will attempt to use the bottom edge of
the flow control gate in place of the screed extension, but this practice should only be
allowed in tapers or short irregular width areas. The flow control gates lack the weight
of the screed extension, lack vibration transmission into the asphaltic mat and tend to
ride up above the elevation of the asphaltic mat being placed by the main paver screed.
When necessary to pave parking shoulders or lanes of less than 10 feet in width (standard
screed length), the contractor may wish to employ cut-off shoe or plate. The cut off plate
fits within the flow control gate and in advance of the front edge of the screed and cuts
off the flow of asphaltic material to the screed. Various widths of cut-off shoes are
available and generally bolt in place. As a general rule, cut-off shoes work quite well
with problems arising only if the asphaltic material works itself under the bottom plate of
the shoe, which will then ride up causing an irregular edge and surface elevation variation
on the m at. Should this occur or should the screed have to be raised, it will be necessary
to remove all the asphaltic material from around and over the cut-off plate to properly
clean and realign the device.
Another paving accessory which is becoming more common as newer pavers with
extendable screeds replace older models is an adjustable screed end which can be
depressed or elevated independent of the main paver screed. This device varies in design
and length from company to company, but, in general, the outer 3 feet of the extendable
screed rotates around an axis and can be controlled from the back of the screed to reduce
or increase the cross slope or pavement thickness in the distance so angled. This change
is cross slope allows the curb height above the asphaltic mat to be varied, thereby
utilizing existing curb lines without replacing or burying them.
When the roadway edge is to be beveled on a 1 to 3 slope, a slope plate is often attached
to the outside edge of the screed. This plate bolts in place and serves as a strike off to
produce the required beveled edge. Also used in combination with the slope plate is a
weighted lawn type roller which mounts to the outside of the screed and is pulled along
behind the beveled asphalt edge to provide compaction and a finished surface on the
asphalt.
70
Original Date: 1/3/94
Revised Date: 05/27/16
Finally, most brands of pavers furnish an automatic cross slope or slope per foot meter
which is capable of placing at a constant cross slope on the asphaltic mat being placed
or can apply continuous adjustment, provide transitional sections for superelevated
curves. The use of this item is usually limited to new construction, as extensive amounts
of asphaltic material can be required to obtain a specific cross slope on an existing
roadway. The constant slope will usually bury the curb line due to settlement in the
existing roadway.
(c) Automatic vs. Manual Screed Control – On new construction where the initial lift of
asphaltic material has been placed by using an established grade reference system, the
subsequent base lifts should be placed by using the traveling grade reference (ski pole)
with the wearing course placed by established grade referenced and manual screed
control.
On wedge courses, established grade references should be used to reestablish the
roadway centerline, edge lines for drainage and superelevations for curves and
associated transitions. When wedge courses are placed to develop surface smoothness
and correct base deficiencies, or in combination with roadway surfacing and texturing
operations, the traveling grade reference should be used and overridden as needed for
transitions or excessively long low areas (40 feet or more).
On wearing course overlays, the traveling reference should be used unless preceded by a
wedge course or precluded by traffic control problems due to narrow lane widths.
Quantity overruns in asphaltic material can occur rapidly when grade control is left
strictly to the automatic screed control devices. Plan quantity tonnages are based on an
assumed nominal thickness which may or may not be attainable when the screed is
controlled by an automatic device designated to average high and low areas in the
existing pavement. Unless the surface being overlaid is correct for grade and cross slope,
it is impossible to obtain both stated nominal thickness and automatic screed control.
Manual Screed control is practical when qualified personnel are operating the screed ant
eh paving speed of the paver is controlled so that observable elevation corrections can be
made as the work progresses. The paver is equipped to carry a constant grade at the
elevation set by the manual controls on the screed.
407 TACK AND PRIME APPLICATION
Weather conditions will, in large part, govern the paving operation, especially in the application
of tack and prime coats. Both prime and tack coats cannot be placed when the ambient or surface
temperature of the pavement is below 40 ° F or on any wet or frozen surface. The temperature
restrictions may be waived by authorization from the Director.
Before any prime or tack coat can be applied, the surface must be properly prepared. When the
surface is existing asphaltic concrete or Portland cement concrete pavement, preparation will
include sweeping, removal and repair of spalled joints, removal and repair of blowups and base
71
Original Date: 1/3/94
Revised Date: 05/27/16
failures. When the prepared surface is soil or compacted rock, it shall be proof rolled, conform to
the proper cross section and be moistened slightly to control dust at time of application. Moisture
content is to be controlled in aggregates so as not to exceed 2/3 of optimum moisture at the time
of placing.
Should base concrete be constructed prior to placing of asphalt, the concrete surface should be
cured with an approved grade of Emulsified Asphalt Tack (SS1 or SS-1H). Application
temperature should be specified by the Resident Engineer.
The prescribed application rate for tack coat by specification ranges from 0.2 to 0.1 gallons per
square yard and for prime coat from 0.2 to 0.5 gallons per square yard. The rate of application is
dependent on the surface to be paved. Typically, the lowest rate of application will be on a
surface that has been textured, with increasing amounts of tack required on asphalt and concrete
surfaces. Tack should never be placed on aggregate surfaces.
The rate of application should be tempered by the following considerations:
(a) Puddling of liquid asphalt, especially in the striations of textured asphalt, will produce a
bleeding problem and a pickup problem on roller surfaces.
(b) Tracking of asphaltic liquids onto an adjacent asphalt mat by crossing vehicles or
asphalt hauling trucks should be prohibited as undesired materials will adhere to the new
surfaces.
(c) The 600 foot limit of liquid asphalt placement in advance of the paver and the break
period for tack may produce a tracking or a splatter/pickup problem for crossover
vehicles of motorists in metropolitan areas even when properly barricaded.
(d) Recently placed wedge or intermediate asphalt courses require only a modest tack
application and then only if dirty or dust covered. The volume of material required will
vary from plan quantity in the contract due to the many variable field conditions present.
When emulsified asphalt is used for a tack coat, it may be mixed with water not to exceed a 50
percent mixture; however, the application of the mixture will result in the content of emulsion
being spread at the specified original uncut rate. The amount of water will directly control the
speed of curing in the emulsion and will be responsible for the speed at which any paving may
proceed when the distance factor is controlled. For liquid asphalts, curing time will, in general,
be a minimum of 12 hours. In most cases, liquid application will not be governed by a specified
distance limitation.
Calculating Quantities – It is important for the inspector to know the gallons of primer required
on a given job. This quantity can be computed by using the following formula:
FORMULA 407.0 – CALCULATING APROX. LIQUID ASPHALT QUANTITIES
72
Original Date: 1/3/94
Revised Date: 05/27/16
Where:
Gallons=
L×W×R
9
L = Length in feet
W = Width in feet
R = Rate of application
408 PAVING OPERATION
408.1 UTILIZING THE VARIOUS SCREED CONTROLS
Automatic screed control for full depth construction will be subject to the following:
When placing full depth main line pavement without curb and gutter, and established grade
reference will be required to properly establish the subgrade elevation and first lift. For paving
conditions of multiple lane widths, the traveling reference may be used subsequent to the initial
lane placing. As the other lanes will depend on the placing accuracy of the initial lane (when the
traveling reference is uses in this application), care must be taken to ensure the accuracy of the
asphalt application vs. the established grade reference. Any variation from the established grade
will be justification for disqualification of the use of the traveling reference and required use of
the established grade reference for each lane. The established grade reference is intended to
provide an accurate longitudinal grade and proper cross slope in the first lift of material so that
subsequent lifts may be placed with minimal adjustments in profile grade or cross slope. The
idea that errors made in the initial lift can be corrected in the subsequent lifts is inaccurate.
Proper inspection to obtain a correct first lift will make the rest of the placing a matter of course.
The initial lane placing of the first lift on a roadway without curb and gutter should always be at
centerline paving outward to the shoulder.
When placing full depth main line pavement with curb and gutter, the established grade
reference may be assumed to be the front line of the gutter section provided the curb and gutter
section was poured on grade and in the proper alignment. When this is the case, the traveling
reference may be used for the first lift placing with only a check at centerline being required to
confirm a proper slope. Under these circumstances, the initial lane installation should be adjacent
to the gutterline with paving proceeding to centerline. Again, the accuracy of placing of the first
lift will control the ease of completion of the paving operation.
The remaining layers of base asphalt will be merely reproducing the longitudinal grade and cross
slope of the first lift placed. Should a base failure occur or error exist in the first lift, corrective
action is best accomplished by using an established grade reference.
If removal of base material is required, be sure that portions of the first lift beyond the removal
area are not disturbed or elevated. The reinstalled asphaltic concrete material used to correct a
failure should be allowed to properly cool before the next lift is placed.
73
Original Date: 1/3/94
Revised Date: 05/27/16
The final lift of asphaltic concrete will be the wearing surface. The wearing surface will be
placed without the use of the traveling reference but will take into consideration the established
grade reference. The thickness of wearing surface will be adjusted to produce the smoothest
possible riding surface which will correspond to the original established grade reference. In
many cases, trades will have to be established which will check existing grade against the
established grade reference to produce thickness dimensions at centerline for the contractor’s
use.
On roadways with curb and gutter, the asphalt lift for the wearing surface should be left ¼ to 3/8
inch higher than the matching gutter to allow for compression upon compaction. In flat areas
where the wearing surface is placed to the curb face, a 4 foot level should be used to check
drainage before any compactive effort is applied to the lift. The contractor should provide the
necessary hand labor to lute the asphalt to establish a water line that will drain. The water line
must be established before rolling occurs; it is almost impossible to rework compacted asphalt
without producing a segregated, open surface. This method applies only to full depth
construction with or without curbs.
408.2 WEDGE COURSE
When the paving involves a wedge course and a wearing surface course, automatic screed
control will be required as follows:
In areas where the pavement surface is irregular, rutted, wash boarded, or where curves are
improperly superelevated, a leveling course will be required. The purpose of a leveling course is
to establish a smooth riding surface with the proper cross slope. In these instances, an established
grade reference will be the easiest method of grade control. A traveling reference may be used in
isolated areas; however, in extensive areas needing correction or in superelevation, the manual
override of the automatic system will be required.
When a leveling course is to be applied to obtain a constant desired cross slope, the traveling
reference is best utilized. In this particular case, the thickness of the leveling course will be a
major consideration. Because a uniform slope is being applied to a more or less parabolic
surface, placing thickness will vary greatly from centerline to edge line. In order to obtain proper
compaction and minimize the amount of asphaltic concrete required, a beginning trial thickness
of one inch over the existing roadway high point should be used. The thickness can then be
revised as required. Under no circumstance should the screed be allowed to drag the existing
surface unless so agreed by your Regional Project Engineer Supervisor.
When spot wedging of the surface is required, the traveling reference is best employed. Because
of the small areas required to be wedged, featheredging of the asphalt placed will also be
required. This featheredging and any handwork on asphalt edges should be accomplished with an
asphalt rake or lute designed for use in this application. The method of featheredging involves
tapering the lift thickness from full depth to zero in an area of several feet. By raking the material
at the edge it is possible to segregate the larger aggregate from the mix, leaving the finer material
74
Original Date: 1/3/94
Revised Date: 05/27/16
to be compacted. In so doing, the lift can be tapered to prevent a bump. This practice should be
used sparingly and not on the wearing surface as raveling may occur with traffic.
When the wedge or leveling course has placed the roadway surface at the proper cross slope, the
wearing course may be placed. The wearing course may be applied by using either the traveling
reference or the shoe sensor (after the first lane has been applied using the traveling reference).
The traveling reference is the preferred method of automatic screed control and may be required
for screed widths in excess of one lane each direction.
When the paving involves an overlay of the existing surface, a shoe type sensor may be used to
place the asphalt material. Here again, manual override of the automatic screed control may be
required to produce the best riding surface. For road widths greater than one lane in each
direction, a traveling reference may be required.
408.3 MAIN LINE CONSTRUCTION PROCEDURES
The following procedures are accepted as standard operational procedure in this area when
placing asphalt:
Initial lift thickness for base courses, wearing courses and overlays is obtained by placing either
an uncompacted leveled pad of asphalt or lumber of the proper thickness under the screed of the
paver. The screed should be placed flat on the supporting surface, and the initial 5 to 10 feet of
paving will require handwork to obtain the proper surface with a consistent cross slope and
longitudinal grade. Normally, the screed will sink when paving begins until the automatic
controls have an opportunity to establish the proposed grade. Adjustment to the screed, which
overrides the automatic controls, will require 5 to 10 feet of machine movement to take effect.
The beginning area of each lane for the length of the paver should be checked by string line to
determine the accuracy of the paving. Handwork will be required as necessary to eliminate high
and low areas. Once paving has begun, it should be kept on a continuous basis with as few stops
as possible. The area where the screed begins to move after each stop should be reviewed for
possible handwork required to maintain a uniform surface.
Calculating Quantities – It is important for the inspector to know the approximate tonnage of
asphalt required on a given roadway. This quantity can be computed by using the following
formula:
Where:
FORMULA 408.3 – CALCULATING APROX. ASPHALT TONNAGE
𝑇𝑜𝑛𝑠 =
𝐿×𝑊×𝐷×𝑁
18000
W = Width in feet
75
Original Date: 1/3/94
Revised Date: 05/27/16
L = Length in feet
D (For compactive thickness of ½ inch) = 55
D (For compactive thickness of 1 inch) = 110
D (For compactive thickness of 2 inch) = 220
D (For compactive thickness of 3 inch) = 330
D (For compactive thickness of 4 inch) = 440
Type of Material Used
N (“X” & “C” Mix) = 1
N (Non-Skid Trap/Limestone) = 1
N (Non-Skid Slag/Limestone) = 1.12
408.4 BUTT JOINTS
In areas where butt joints have been provided or a solid vertical edge will bound the asphalt
pavement, the uncompacted wearing course should be placed ¼ inch to 3/8 inch higher than the
solid in-place surface. The solid surface asphalt surface interface may require handwork to assure
an even juncture after compaction by the roller. Where butt joints are used, the course should be
rolled transversely on the initial pass with the roller’s weight equally borne by the solid surface
and the asphalt surface. The subsequent roller passes should be longitudinal across the butt joint.
Where curb and exposed gutter abut the wearing course, the initial pass of the roller should bear
on the gutter section and the asphalt paving; Joints at the curb and gutter should not be pinched
by rolling at the interface surface on the wearing course, as low areas may develop at the front
edge of the gutter which will not properly drain. It is acceptable for the pavement wearing
surface to be slightly elevated above the gutter section at the interface.
408.5 TRANSITIONAL JOINTS
When no butt joint is provided, a transitional section will be necessary to proceed from the
existing surface to the new wearing course. The transitional section will be produced by
featheredging the asphaltic material as previously explained. Transitional sections should be a
minimum of 5 feet in length to prevent an abrupt elevation change.
Transitional sections will also be required where a wedge course is to be stopped short of a
bridge. The transitional section should generally be stopped prior to the approach slab or a
minimum of 30 feet,
408.6 CONSTRUCTION JOINTS
At the end of each day’s run, a transverse construction joint will be installed. This joint will be
made vertical, true to grade and cross slope and densely compacted. Handwork at the joint will
be held to a minimum. A hard, full depth edge board held in place will be required when rolling
the joint. This will prevent rolling down the edge during compaction. Construction joints will not
76
Original Date: 1/3/94
Revised Date: 05/27/16
occur at the same location in succeeding layers but will be offset at least 20 feet from each other.
When traffic is to use the asphaltic concrete for a driving surface before the entire project is
completed, a paper joint will be installed at the end of each day’s run and then removed before
the paving is resumed. Paper joints are produced by placing roofers felt or any non-bituminous
impregnated paper on the surface in advance of the joint. An approximately 6 foot length of
paper will be required for the full width of the lane being placed.
The paper should be placed so that 2/3 protrudes past the joint ahead and 1/3 rests on the newly
placed asphalt. A full depth header (usually 2 x 4’s) is placed on the paper at the joint location
and the trailing 1/3 of the paper is folded forward over the header. Asphaltic concrete is then
placed atop the paper and header. The asphaltic material is transitioned to compensate for the
elevation offset (on the paper) and then rolled. This procedure allows for rapid installation and
removal and a vertical joint for resumed paving operations.
408.7 LONGITUDINAL JOINTS
Longitudinal joints will be produced while asphalt is being placed. The longitudinal joint to be
produced on the outside edges of pavements without abutting cubs or curb and gutter sections
will be created by an edging plate so set as to produce a 3 to 1 beveled edge to the surface of the
roadway. The remaining longitudinal joints in the driving lanes will be vertical to the surface of
the roadway. The remaining longitudinal joints in the driving lanes will be vertical to the surface
of the roadway. If necessary, a lute or rake may be used to correct slumped areas. Longitudinal
joints are expected to be straight and at the lane line. To produce a tight joint, prime or tack may
be applied to the existing surface when adjacent lanes are placed. All such joints should be luted
flush. The joint should be so rolled (pinched in) as to produce a level, well compacted, tightly
fitted joint. When joints are run over or rounded off, it will be necessary to overlap, lute and
handwork the joint to produce a smooth joint that will not separate or hold water.
408.8 COMPACTION REQUIREMENTS
Compaction in asphaltic paving is obtained by using a combination of self-propelled steel wheel
rollers and self-propelled pneumatic rollers. Compaction requirements for base asphalt (Type X)
are a minimum of 95 percent of the laboratory determined standard, a minimum density of 98
percent for wearing surfaces (Type C and D) and 96 percent for non-skid mixes. Density
penalties may be assessed for insufficient compaction or, in some cases, the pavement will be
removed and replaced.
408.9 ROLLING
A well-engineered and executed construction job employing the most advanced grading and
leveling techniques and the best of materials and workmanship can be cancelled entirely by
slipshod methods in rolling and finishing. Because of this, the value of an experienced rolling
operator cannot be disputed. A definite rolling pattern should be established to assure a
uniformly and correctly compacted mat.
77
Original Date: 1/3/94
Revised Date: 05/27/16
The rolling sequence should be as follows:
(a) Breakdown rolling – Steel wheel rollers are designed to move in a slow, continuous
manner with the drive wheel towards the paver. The initial rolling of the pavement will be
made as soon as possible after placing by the paver. Rolling will always progress from
the low side of superelevated curves toward the higher side. For pavement abutting curbs
or curb and gutter sections, the rolling will proceed from the curb or from the edge of
gutter toward the centerline (one lane each way). For pavement not abutting curbs or
curb and gutter sections, the rolling will proceed from the curb or from the edge of gutter
toward the centerline (one lane each way). For pavement not abutting curbs or curb and
gutter sections or for additional lanes (two lanes each way or more), rolling will be at the
abutting longitudinal joint first and then from the curb side toward centerline. Each pass
of the roller should overlap the previous pass by one half the width of the drive wheel,
and the change of direction at the end of each pass should be made without bringing the
roller to a complete stop or spinning the drive wheel on the pavement. Under no
circumstance should the roller be stopped and left in place on the hot asphalt. All
abutting longitudinal joints should be pinched in by rolling on the previously compacted
surface and the edge of the new mat. Any displacement in the asphalt surface caused by
the action of the roller will be corrected by handwork in an acceptable manner.
Pavement edges which are displaced by the rolling process will be immediately corrected
by hand methods as required. Hand tamping of inlet throats or any inaccessible area,
will be performed as soon as is possible after placing by the paver. Transverse rolling of
the pavement will be required to remove high spots in the pavement at transverse
construction joints and in intersections. Normally, rolling will be performed in straight
lines parallel to centerline; however, rolling in intersections should follow the curb
rounding or direction of travel of the automobile. Where drainage may be a problem, a
check of the water line should be made after the initial rolling, and any hand tamping
necessary to provide flow should be performed immediately. The termination of each
pass by the roller should be staggered to prevent irregularities.
(b) Compacting – After completion of the initial rolling, the pneumatic roller may be placed
on the new lift. The purpose of the pneumatic roller is to produce compaction in the
freshly placed asphalt. In order to obtain maximum compaction without cracking or
marking the pavement, rolling by the pneumatic roller must be closely controlled.
Generally the asphaltic concrete must be between 275° F and 300° F to obtain maximum
compaction. The best indication of proper rolling is to be able to place the pneumatic
roller on the layer so that the surface is indented without cracks appearing in the surface.
The newly placed lift should be rolled in a manner similar to the steel wheel roller
method with emphasis placed on a uniform speed and equalized coverage of the roadway.
Should marring or cracking of the pavement occur, the rolling should be discontinued
temporarily. In critical temperature periods, ambient temperature, wind velocity and
surface temperature will be major factors in determining when to roll with the pneumatic
roller. Because of the narrow temperature range which restricts the ability to obtain the
required compaction, this sequence of rolling will demand the most intense inspection.
78
Original Date: 1/3/94
Revised Date: 05/27/16
(c) Final rolling – After the pneumatic rolling sequence is completed, the final rolling, with a
steel wheel roller, of the pavement may be commenced. As previously emphasized,
temperature of the pavement will again be the controlling factor. The purpose of the final
rolling is to remove all marks or marring of the surface and leave a uniform, compacted,
impervious wearing layer. Temperature control is critical as a too hot surface will not
properly seal and lose compaction and a too cold surface will have an open, rough,
marred appearance. As a general rule of thumb, the asphalt should be sufficiently hot so
as to produce steam from the moistened roller surface (220° F to 250° F). Rolling should
be continued until all surface marks are removed. Upon completion of the rolling
operations, pavement may be opened to traffic when the wearing course has cooled to the
ambient temperature or until marring of the surface will not occur.
409 SEAL COAT
409.1 AGGREGATE SPREADER
The aggregate spreader is a self-propelled mechanical spreading unit which is capable of
measuring and distributing rock chips for use in seal coating operations. The spreader is designed
with a rear mounted hopper of variable capacity which is filled by direct discharge from a dump
truck. The chips are conveyed to the discharge gates by means of a conveyor belt which is
controllable by manual override or by automatic sensors mounted in the discharge gate area
which monitor the volume of chips present at any time. The discharge gates vary from 6 to 12
inches in size with the smaller gates mounted on the outside. Each gate is independently
adjustable as to the volume of aggregate chips being discharged.
Inspection is limited to checking the gates for the proper amount of chips being discharged and
the automatic load capacity sensor’s operation. There are no automatic alignment or elevation
controls. The hopper should also be periodically checked for deleterious material often present in
stockpiled chips.
Seal coats are normally used in shoulder areas adjacent to main line pavement areas and for
wearing surfaces on existing concrete and asphaltic concrete streets.
At a minimum, the following equipment will be required to place a seal coated surface: power
distributer, rotary broom, 5 to 8 ton pneumatic roller and a self-propelled chip spreader.
Seal coats may not be placed when the ambient temperature or surface temperature is below 70°
F (unless authorized by the director), when the surface is wet or frozen, or when weather
conditions prevent proper handling of the material required. In addition, the surface to be
covered by the seal coat must be swept and free of debris. The application of the bituminous
material will be performed by a pressure distributor. The asphaltic material will be heated to a
temperature specified by the Resident Engineer and within the range cited in the Specifications
with the exception of asphalt cement which will be between 315° F and 350° F. The inspection
of the application of bituminous material will include checking for cleanliness of the surface to
79
Original Date: 1/3/94
Revised Date: 05/27/16
be covered, uniform application of material, temperature of material being applied and traffic
control. The surface must be cleaned and free from oil or grease concentrations. For shoulders,
the rock grade must be thoroughly and completely compacted and leveled to the proposed grade.
The moisture content restrictions for Type 1 aggregate will apply as for the asphaltic products.
The grade of the bituminous material will be specified in the contract. The grade of the
emulsified asphalt will be designated by the Specifications and will depend on the type of cover
aggregate to be specified. The application rate will be established for asphalt cement are: 1.25
gallons RC-3000 equal 1 gallon asphalt cement, 1.25 gallons MC-3000 equal 1 gallon asphalt
cement, 1.82 gallons RS1 equal 1 gallon asphalt cement, 1.67 gallons CRS1 equal 1 gallon
asphalt cement, 1.54 gallons CRS2 equal 1 gallon asphalt cement. Normally, the straight
application rate of base bituminous will range from 0.24 to 0.30 gallons per square yard,
depending on the condition of the pavement surface. The material will be applied in a uniform,
continuous spread without gaps or overlaps. The bituminous application will completely cover
one lane to the lane line and will be placed at a speed which will not exceed that of the chip
spreader capacity to place the chips.
Placing of the aggregate chips will commence as soon as the bituminous material is placed and
will continue at a rate equal to the bituminous placing rate. Normally, the cover aggregate will be
placed within 2 minutes of the bituminous material. The cover aggregate will be uniformly
spread by a mechanical spreader at a controlled rate established by the Resident Engineer (if not
stated in the Specifications) varying from 18 to 25 pounds per square yard. Immediately after
spreading, the surface will receive two complete passes by the pneumatic roller. After the
embedded chips have become firmly set in the asphalt binder material, the surface will be lightly
swept. The sweeping operation should take place the day following the application of the
aggregate. The contractor is required to maintain the new surface for up to 4 days. Any areas of
bleeding bituminous material will be rechipped and rolled as needed. The entire surface will be
swept free of chips by the contractor as part of the contract.
Inspection of the operation will be mainly concerned with the placing rate of chips, the condition
of the chips and the degree of embedding. The chips should be surface dry for all applications
except asphaltic emulsions when surface moisture is allowable and occasionally preferred (5
percent maximum by weight). The chips should be embedded in the bituminous material to a
depth of ½ to 2/3 the size of the chip. Raveling will occur with too light an application of
bituminous material, and excessive amounts will result in bleeding on the surface. The
application rate must be field controlled by the Resident Engineer as work progresses. Traffic
control during the placing operation will entail closing one lane to traffic and keeping it closed
until all rolling is completed. The contractor will provide a pilot vehicle to control speed in the
project area to a maximum of 20 mph for at least 2 hours after rolling is completed.
When double seal coats are specified, they will be placed in a similar manner with the following
exceptions: the first seal coat will be placed full width before any part of the second seal coat is
placed; the second seal coat will be placed during the same day as the first seal coat, and the
placing of the first seal coat will be limited as necessary to ensure compliance.
410 PAVEMENT SURFACER
80
Original Date: 1/3/94
Revised Date: 05/27/16
In recent years, the pavement surfacer (also called Rotomill, Cold Planer) has been used with
increasing regularity. The pavement surfacer has the advantage of being able to remove the
surface irregularities in concrete and asphalt pavement and leave a textured, skid resistant
surface.
Two types of surfacer are in common use. The first is a small unit, non-propelled and usually
attached to a motor patrol in place of the blade. The unit is hydraulically powered and is
designed for use in small, isolated areas. The surfacer is incapable of loading reclaimable
aggregate and is not used for most main line areas.
The other type of pavement surfacer is self-propelled, either track mounted or mounted on
pneumatic tires, equipped with automatic grade and cross slope control sensors and an integral
loading, dust control and aggregate reclamation system.
Inspection of the equipment includes the following:
(a) The surfacer is equipped with a milling cutter head composed of carbide tipped teeth
affixed to individual discs. The discs are mounted so as to provide a staggered cutting
wheel with teeth on 6 inch centers around the circumferential surface of the milling head.
The length of the teeth should be monitored for conformity around the milling head.
Replacement teeth must be adjusted to conform in height to existing teeth.
(b) The cutter head height controls the depth of cut performed by the machine. The depth of
cut is controlled by an automatic system which provides both profile grade and gross
slope sensors. The profile grade is the most significant grade for material removal with
the cross slope being controlled as a constant grade set by the operator. The profile
grade will normally be established by a 30 foot ski pole mounted to run adjacent to the
machine which will provide longitudinal grade control in each driving lane. In certain
areas, a string line may be required to obtain the grade required. In either case, the same
procedures for inspection discussed for asphalt pavers will apply. A manual override of
the automatic system must be functional at all times for grade adjustment.
(c) The surfacer loading and reclamation system must be functional and in operation at all
times. A back up system must also be provided in case of breakdown. The system should
remove and load all aggregate milled from the surface.
Inspection of pavement surfacing and texturing will mainly involve grade control, removal of all
loose material and the smoothness of the surface obtained. The grade control will be set and
controlled by a traveling reference used to guide the machine. The height of the cutter head will
be controlled by the operator and will be a stated amount from the plan or as established by the
Resident Engineer when deemed necessary. In areas of washboarded, depressed, elevated, or
extremely irregular pavement sections, an independent grade control may be required. When
necessary, the Resident Engineer will enumerate these areas to the contractor who will establish
81
Original Date: 1/3/94
Revised Date: 05/27/16
the independent grade control and maintain said grade in a satisfactory manner until the final
desired grade is obtained.
When removal of material will leave a vertical edge at the lane line in excess of 1-1/4 inches at
centerline or 2 inches at the shoulder, the longitudinal face will be sloped so as not to present a
hazard to traffic.
Transverse beginning and ending joints will also be transitioned to provide a smooth ride. All
loose material will be cleaned from the pavement on a concurrent basis and removed from the
project. Before any texturing is performed, a dust control system must be in place and in working
order on the equipment. Before any pavement is opened to traffic, it must be cleared or swept to
remove any residual cuttings and dust. The contractor will be responsible for removal of all
cuttings and debris from the project. The smoothness of the completed surface will be to within
¼ inch in 10 feet, and adjacent lanes will be within 1/8 inch of the same elevation (plus or
minus) at the adjoining edges.
411 TESTING
In order to properly monitor the thickness and density of the asphaltic material being placed on
the project, a variety of testing procedures will be implemented by personnel from the Materials
Testing Laboratory. It will be necessary to schedule the required personnel and equipment to
obtain the testing information needed on a daily basis (24-hour notice).
Thickness and compaction results will be provided on the project, as paving proceeds, by
personnel from the Materials Testing Laboratory utilizing the nuclear density gauge. Testing will
normally be in 2,000 foot increments per lane will a series of test readings being taken in a small
area to obtain an average result. In addition, individual or small groups of readings may be taken
to obtain or modify the rolling pattern in use or provide information on air voids necessary to
modify the mix design. It is often necessary to monitor compaction behind each roller to
determine over rolling or under rolling which, when combined with the temperature of the
asphalt mat, will provide the best roller pattern and time available to obtain maximum
compaction. The contractor’s representative must be kept abreast of the results so obtained and
should take appropriate action to rectify any problems or compaction deficiencies. Penalty
payments will be assessed for insufficient compaction, and continuous compaction failure will be
considered cause for a Stop Order and possible removal of the asphaltic material at the
contractor’s cost. A graduated scale of penalty payments will be assessed in 500 foot intervals
when encountered. These compaction results will be obtained by core sample taken from the
newly placed asphalt mat. Penalties for inadequate compaction will always be based on results
obtained from cored samples.
Nuclear density testing will not be required on wedge courses unless a nominal thickness is
specified. Base asphalt will, in general, be spot checked with the nuclear density gauge and cored
to determine thickness and compaction.
82
Original Date: 1/3/94
Revised Date: 05/27/16
Surface smoothness will be tested by using a 10 foot straightedge parallel to centerline in each
wheel lane. A maximum deviation of 1/8 inch in 10 feet will be allowed on the top layer of
asphaltic material. At transverse construction joints, a maximum of ¼ inch in 10 feet will be the
maximum deviation. Corrective action for non-compliance with the deviations established may
include grinding and/or removal and replacement.
412 CHECK LIST – FLEXIBLE PAVEMENT
COMPACTION OF FOUNDATION
(a) Have all courses of the foundation been compacted to required density?
OLD ASPHALT PAVEMENT
(a) Potholes patched?
(b) Necessary patches made?
(c) Loose material and “fat” patches removed?
(d) Depressions filled and compacted?
(e) Fog seal used on surface that has deteriorated from oxidation?
(f) Emulsified asphalt slurry seal applied on old surfaces with extensive cracking?
RIGID TYPE PAVEMENT
(a) Pavement undersealed where necessary?
(b) Pre-molded joint material and crack filler cleaned out?
(c) All “fat” patches removed?
(d) Severely broken pavement removed and patched?
(e) Depressions filled and compacted?
INCIDENTAL TOOLS
(a) Incidental tools comply with Specifications?
(b) Necessary tools on the job before work begins?
ENGINEER AND CONTRACTOR
(a) Engineer and his inspectors have held a preliminary conference with the appropriate
contractor personnel?
(b) Continuity of operations planned?
(c) Determined number of pavers to be used?
(d) Determined number and type of rollers to be used?
(e) Determined number of trucks to be used?
(f) Width of spread in successive layers planned?
(g) Is it understood who is to issue and who is to receive instructions?
(h) Determined weighing procedure and number of load tickets to be prepared?
(i) Procedures for investigation of mix agreed upon?
(j) Method of handling traffic control established?
PREPARATION OF SURFACE
(a) All surfaces that will come into contact with the asphalt mix cleaned and coated with
asphalt?
(b) Uniform tack coat of correct quantity applied?
ASPHALT DISTRIBUTER
(a) Asphalt distributer complies with Specifications?
(b) Heaters and pump in good working condition?
83
Original Date: 1/3/94
Revised Date: 05/27/16
(c) All gauges and measuring devices such as bitumeter, tachometer and measuring stick
calibrated?
(d) Spray bars and nozzles unclogged and set for proper application of asphalt?
HAULING EQUIPMENT
(a) Truck beds smooth and free from holes and depressions?
(b) Trucks comply with Specifications?
(c) Trucks equipped with properly attached tarpaulins?
(d) For cold weather or long hauls – truck beds insulated?
(e) Do trucks (when unloading) and paver operate together without interference?
(f) Method of coating of contact surfaces of truck beds agreed upon?
(g) Truck bed to be raised slowly to prevent segregation?
PAVER
(a) Paver comply with Specifications?
(b) Governor on engine operating properly?
(c) Slat feeders, hopper gates and spreader screws in good condition and adjustment?
(d) Crawlers adjusted properly?
(e) Pneumatic tires contain correct and uniform air pressure?
(f) Screed heater working properly?
(g) Tamper bars free of excessive wear?
(h) Tamper bars correctly adjusted for stroke?
(i) Tamper bars correctly adjusted for clearance between the back of the bar and the nose of
the screed plate?
(j) Surfaces of the screed plates true and in good condition?
(k) Mat thickness and crown controls in good condition and adjustment?
(l) Screed vibrators in good condition and adjustment?
(m) Oscillating screed in proper position with respect to the vibrating compactor?
(n) Automatic screed control in adjustment and correct sensor attached?
SPREADING
(a) Required number of pavers on job?
(b) Mix of uniform texture?
(c) General appearance of mix satisfactory?
(d) Temperature of the mix uniform and satisfactory?
(e) Mix satisfy the spreading requirements?
(f) Proper paver speed determined?
(g) Surface tolerance checked and adhered to?
(h) Depth of spread checked frequently?
(i) Daily spread checked?
ROLLING
(a) Required number of rollers on the job?
(b) Proper rolling procedure being followed?
(c) Proper rolling pattern being followed?
(d) Joints and edges being rolled properly?
MISCELLANEOUS
(a) All surface irregularities properly corrected?
(b) Efficient control of traffic maintained?
84
Original Date: 1/3/94
Revised Date: 05/27/16
(c)
(d)
(e)
(f)
(g)
(h)
(i)
(j)
Sufficient samples taken?
Are samples representative?
Assistant Inspectors properly instructed?
Inspection duties properly apportioned among assistants?
Records completed and up-to-date?
Safety measures observed?
Final cleanup and inspection made?
Rejected material tickets marked “Rejected” with reason and copies retained?
85
Original Date: 1/3/94
Revised Date: 05/27/16
SECTION 500
RIGID PAVEMENT
501 CONSTRUCTION STAKING
Paving grades will be set on offset stakes determined by the method of paving employed. The
contractor should provide the offset distance required prior to any staking by the Survey Party.
In general, the County will establish pavement grades, radius points, warp grades and flow line
grades for gutters and curb and gutter sections. In all cases, a cut or fill stake will be provided to
determine finished pavement grade or water line grades. “Bluetops” (hubs driven to grade) will
not be provided by the Survey Party. Pavement grades will be established at 50 foot
intermediate and 100 foot stations. Warp grades will be given at points on the radius as specified
on the plans. Grades will also be given at radius points and, when required, at 25 foot intervals
for sharp vertical curves or in areas where drainage is critical.
Upon completion of rough grading by the contractor, areas of roadway should be staked to
facilitate fine grading, placing of aggregate base courses or asphaltic concrete bases and paving
forms. The contractor should request these areas be staked at least 24 hours prior to the expected
work in preparation of the subgrade. The Party Chief should verify the proposed centerline
profile grade and stake the roadway pavement in accordance with these grades and the typical
section applicable as shown in the Construction Plans.
The stake, as shown in Illustration 501A, would indicate the tack point on the hub is 4 feet from
the edge of pavement (perpendicular on tangent, radially on a curve) at Station 28+00-left, and a
cut of 0.33 feet would be required to reach finish pavement grade (measured level from the
paving hub). Elevation will be taken from the highest point of the paving hub, not the tack point.
Radius points are given to indicate the central point of a circle or circular arc employed to
connect two tangent lines. Radius points are commonly placed at street intersections and to
denote radii for drive approaches or sidewalks. The radius stake is accompanied by a hub
containing a tack point to denote the center point. All radius hubs should show the distance of the
radius from the tack point to the edge of pavement or back of curb as shown in Illustration 501B.
86
Original Date: 1/3/94
Revised Date: 05/27/16
ILLUSTRATION 501 – TYPICAL PAVEMENT & RADIUS STAKES
While radius points for pavements are staked to denote edge of pavement or back of curb, care
should be taken because radius points for medians or islands are staked and also marked to face
of curb.
Warp grades are provided on the plan sheets for drainage at intersection roundings. These grades
are mathematically interpolated and may need adjustment to maintain a constant slope in the
water line at intersection roundings. The staking required for warp grades is similar to the stakes
as set for finish paving grades. An offset stake with cut or fill to water line and tacked hub is
required at the staked spacing show on the plans.
502 SLIP FORM PAVING
When slip form paving methods are employed for main line paving, inspection will involve the
following items:
(a) Subgrade Preparation – Subgrade preparation will be as described in the subgrade
preparation established in Section 200. As previously explained, accuracy in establishing
elevation and alignment control is dependent on the string line and the care taken in
establishing it on the proper line and grade. The finished product in slip form paving is
dependent on the string line and the accuracy with which it is set in place; therefore, all
inspections should center around its placement and the reaction of the equipment’s
guidance system in relationship to the established grade and alignment control.
(b) Paving Procedure – The inspection will in large part be as described for stationary form
paving with a great deal of inspection emphasis placed on a consistent slump concrete.
The paving accessory check will be the same with additional inspection emphasis focused
on placing of the keyway and slumping at the edge of pavement. The finishing
requirements will be the same in nature, and the straightedging of the pavement will be
the major item of consideration. The requirements for surface texture, curing and sawing
are discussed later in this section.
Regardless of the method of paving, weather must be considered on all main line pavement
pours. In case of rain, each pavement pour will require a provision for covering pavement which
has not reached its initial set. The contractor must have on hand at all times adequate waterproof
sheeting to cover the full width of the new pavement for the length required. When required, the
sheeting will be placed until the rain is over and then the surface of the pavement refloated and
texturized as needed. In locations where storm water from higher elevations (pavement or other)
is likely to run over the newly placed concrete, steps must be taken to deflect this water so it will
not pass over this fresh concrete. Sandbags, lumber, plastic sheeting, etc. may be used as long as
the do the job. It is best to have a plan and the proper material available at the high end of the
87
Original Date: 1/3/94
Revised Date: 05/27/16
pour. A surprising amount of water will flood the area after several minutes of rain. It is solely
the contractor’s responsibility to assess the risk in paving when the possibility of rain exists and
to provide the necessary precautions.
503 FORMS
When the forms are set for the conventional rail paving methods, the exact subgrade elevation
must be obtained. Prior to utilizing the subgrade planer, the side forms must be secured and the
aggregate surface under the form tamped to prevent settlement. A one foot width beyond the
edge of pavement is provided in the aggregate plan quantities to allow for a stable compacted
base for the side forms.
In order to use the subgrade planer, the form line must be established to the exact finish grade of
the proposed pavement and to the exact alignment. This is possible by the use of the offset
distance and elevation information provided on the paving grade stakes. Normally, a graded
string line is placed on line and graded, and the forms are set to this string line. After the string
line is placed, a visual inspection check for alignment and elevation should be made by eye as
well as by a level and ruler. The paving forms should be securely held in place by staking pins
and should be interlocked before the subgrade planer is mounted on the forms. A minimum of 3
staking pins per 10 foot form should be used to hold it firmly in place.
The subgrade planer used for conventional paving is mounted on wheels that ride on the side
forms and is drawn by a tractor or highlift. The cutting edge is mounted to a transverse beam
which is adjustable for depth below the top form. The cutting edge is composed of individually
adjustable plates which should be checked for alignment by string line before each use. The
subgrade planer is designed to remove small amounts of aggregate on each pass; therefore, the
grade must be close to the proper grade before the subgrade planer can work effectively. The
subgrade planer has the ability to bring the aggregate grade to within 1/8 inch of the proper
elevation by making repeated passes over the compacted aggregate surface. A check of the
required aggregate subgrade elevation may be made at any point on the roadway by pulling a taut
string line from top of form and measuring down the thickness of the proposed pavement. This
depth check should be recorded in the Subgrade Book. A check template may also be used to
indicate the accuracy of the grading operation.
Due to the penalty provisions provided in the Specifications, the aggregate subgrade must be
established to an elevation no higher than 1/8 inch from the proper grade, the proper grade being
the profile pavement grade minus the proposed pavement thickness. This requirement applies
for the full width of the paving section – no compensating section can be allowed for the
aggregate subgrade.
Side forms serve two purposes, both of which are extremely important. First, they confine the
wet concrete so that it is true to line and grade and has vertical edges or properly formed tongueand-groove joints when finished. Second, they support the heavy construction equipment
without settlement or lateral displacement since irregularities in forming, whether due to poor
placement or to poor forms, are reflected in the riding qualities of the pavement.
88
Original Date: 1/3/94
Revised Date: 05/27/16
The side forms must meet the following requirements:
(a) Paving forms are to be of metal with a base width equal to the height of the form except
10 inch forms may have 9 inch bases.
(b) The form shall be straight with no more than 1/8 inch in 10 feet deviation from a straight
plane on the top or ¼ inch in 10 feet deviation on the face of the form. Forms should be
checked by string line and rejected forms clearly marked with paint or other permanent
marking substance.
(c) When “built up” forms are allowed, only 20 percent of the form height may be wood.
The wood applied to the form must be at the base and must be wide enough to afford
uniform bearing for the entire form. No “floating” or suspended forms with open spaces
underneath will be allowed. Crushed stone pushed underneath the forms will not be
acceptable. Forms must be full height and resting on compacted subgrade.
(d) The form should be free of built up concrete, especially on the top finishing edge. The
forms should have attached pin pockets with pin locking devices located in at least three
places per form. Each form should have an interlocking device at each end of the form to
provide a positive means of joining the form line at the joints to provide a neat, tight
joint. Bends or wrinkles in the end or wall of a side form are cause for rejection of the
form. Wood forms for pieces less than standard form length will be kept to a minimum.
(e) Pins for holding forms in place should be of sufficient diameter to be locked in the pin
pocket by the tapered locking device and of such length to prevent movement or
overturning of the form. Pins should always be driven below the top of the form to allow
clearance of the paving equipment wheels. Special attention should be made when
driving pins at or near underground utilities to prevent damage to the utility or service
lines.
(f) Forms to be set in a curve (circular or spiral) will be straight steel forms of 10 feet or less
for curves of 200 feet radius or greater. Straight steel forms of 5 foot length may be used
on curves of 100 feet or greater radius. Wood or steel forms may be used on curves of
less than 200 feet radius with the exception that wood forms may not be used to support a
mechanical paving train. Usually, straight steel forms are practical if the pavement is
topped with dowel on curb. The back of curb is formed with wood and hides the broken
form line of the steel forms.
504 PAVING ACCESSORIES
89
Original Date: 1/3/94
Revised Date: 05/27/16
When the forms are properly set and the prepared subgrade is at the proper elevation, paving
accessories will be placed within the form line.
504.1 KEYWAY
Keyway is used to provide a longitudinal joint at the edge of pavement where curb and gutter
are to be poured. It also is used to provide a slip joint between adjacent lanes. The keyway
acts to produce a barrier to vertical separation and a mechanism for expansion movement in
the pavement.
504.2 BENT BARS
Bent bars are often used in conjunction with the keyway, especially where a change in grade
of the finished surface is involved. Bent bars are usually #5 deformed reinforcing steel bars
cut in 30 inch lengths and bent at a 90 degree angle to allow placement of one leg within the
keyway and the other leg to protrude into the pavement through the pre-drilled keyway. Bent
bars are intended to prevent vertical or transverse displacement of the adjoining pavement
surfaces on different profile grades. In general, all pavement should be held together with
bars to prevent cracking because of movement due to expansion. When keyway and bent
bars are used as a unit, care should be taken to ensure that the keyway is wedged tightly
against the side form and that the bent bar remains inside the keyway during the pavement
pour. The depth of the keyway in the pavement is controlled by support legs which come in
variable heights. A minimum clearance of 2-1/4 inches should be maintained above the
keyway. The bent bars are supported by staking pins and should have a minimum of 3-1/4
inches of cover above the top of the rod. Staking pins without supports are also used to hold
the keyway tightly against the side form. The proper clearance on these items must also be
maintained. In pavement sections where an existing keyway or keyway and bent bars have
been previously included, care should be taken to completely remove any deleterious
material or concrete from the keyway. The keyway should always be washed clean before
and concrete is placed adjacent to it.
504.3 CONTRACTION JOINTS
Contraction joints in concrete are made either by sawing and cracking of the pavement or by
using a grooving tool to form a joint that controls the cracking of the pavement. In either of
the above cases, a load transfer device is placed on the subgrade for inclusion in the
pavement. Load transfer devices are of two types, differing only in the method of bar
support. Type A load transfer devices have longitudinal supports of 1 inch diameter (1-1/4
inch dowel bars required for 9 inch and 10 inch thick pavement) x 18 inch dowel bars. Type
B load transfer devices have transverse bar supports at each 1 inch diameter x 18 inch dowel
bar. Each bar within the devices will have a free and fixed end. The dowel assembly is so
designed as to make the fixed and free ends of dowels alternate for the length of the
assembly. Wire support stirrups maintain the rigidity of the assembly until ready for paving.
It will be necessary to cut the wire braces after the dowel assembly has been installed and
90
Original Date: 1/3/94
Revised Date: 05/27/16
staked. The load transfer device should be designed so as to place the centerline of the dowel
bars at the required height above subgrade. Unless otherwise shown on the Construction
Plans, contraction joints will be placed at a maximum of 20 feet in non-reinforced pavement
and will require a sawed joint to produce cracking. When possible, contraction joints should
be placed at the centerline and at radius points of intersecting streets and driveway
approaches, away from inlet sumps and to intersect manholes in the pavement. The load
transfer device must rest on the top of the prepared subgrade and must be staked in place
with 6 pins per assembly to prevent movement as concrete is placed. The staking pins used
to hold the load transfer device in place should be driven full depth into the subgrade and
should secure the bottom of the dowel support assembly. The dowel assemblies should be
placed on the subgrade with a minimum of 6 inches clearance from the side formto the
centerline of the first load transfer dowel. The location of the dowel assemblies will be
established by measurement on centerline for spacing determination with all load transfer
devices set at 90 degrees to the curb line form for tangent section and at curves to produce a
radial line. The form line will be so marked as to indicate the center of the load transfer
device for sawing following the paving operation. When the dowel assembly is in place, the
free end of each dowel will be completely greased around the circumference for one-half of
its length plus two inches with an approved grease, usually a lithium-base type containing
graphite, and the supporting stirrups cut to allow free movement of the load transfer dowels.
504.4 EXPANSION JOINTS
Expansion joints will be placed at areas designated on the plans, at all bridges and box
culverts (where the top of the box is used as pavement) and in conjunction with bridge
approach slabs. County expansion joints are either 2 inch thick bituminous treated expansion
material (Type A2) or 1 inch thick bituminous treated material (Type A or AA). The joints
will be full width and full depth of the pavement. The top of expansion joints will be filled
with sealer as shown in the Standard Drawings. Expansion joints will be installed as shown
in the Standard Drawings in the Construction Plans.
504.5 CONSTRUCTION JOINTS
Construction joints are used to stop a pavement pour at a location other than at a normally
designated expansion or contraction joint. Construction joints can only be made at an
established expansion or contraction joint or at a distance of not less than ten feet from these
joints. Construction joints will utilize a header set so as to provide a bulkhead at the desired
location. The header must be full depth and full width. A keyway with bent bars should be
attached to the header for the full width of the pavement at a construction joint. Care must
always be exercised at a construction joint to provide a smooth, true plane surface at the joint
and at the adjoining pour after the header is removed. The header should be set by string line
and checked both longitudinally and transversely with a straightedge after finishing
operations are completed.
504.6 OTHER APPURTENANCES
91
Original Date: 1/3/94
Revised Date: 05/27/16
Other appurtenances on the subgrade will also include:
(a) Straight reinforcing steel bars supported by staking pins or paving chairs to create a Type
B or Type F joint for longitudinal contraction joints.
(b) False forms in the pavement for entrance connections where integral curb is used at the
edge of pavement. Usually a 6 inch wide box-out is formed for the length of the drive
approach, radius point to radius point, with a keyway and bent bars provided for future
connections.
(c) Box-outs for paving at manholes. A full depth square, one foot wider than the outside
flange of the manhole frame unit, should be formed with a paving contraction joint
established at the points of the square if possible. Expansion material should be placed
around the perimeter of the box-out when the square is poured.
(d) Throw-outs for ramps, left turn lanes and pavement widenings. Throw-outs or turn-outs
from main line pavement will require a two foot widening in a distance of 20 feet. The
throw-out is required to prevent cracking and slab displacement on a narrow, tapered
piece of pavement in a widening section which begins at a point and increases in width at
a uniform rate. A throw-out will require a keyway and bent bars along the roadway fence
and at the end form.
504.7 DOWEL BARS FOR CURB
Dowel bars for “doweled on curb” must be placed at the proper depth and spacing while the
concrete is still plastic. The bars should not be driven in the concrete with a hammer after the
concrete has attained its initial set. These bars are typically #4 bars placed on 24 inch centers
with a length of 3 inches less than the pavement thickness plus curb height.
505 JOINT DETAILS
The joint spacing, including the required type of joint at each location, and the joint details can
be found in the Standard Drawings. These standards are included in the Construction Plans. If
this sheet is missing from the plans, these details are also available in the Design Criteria Book.
506 CONCRETE PAVING EQUIPMENT
Concrete paving equipment is of two types, that which rides on stationary side forms and that
which rides on the prepared base (slip form). The purpose of all mechanical paving equipment is
to consolidate the pavement mass, to provide a finished surface at the proposed cross sectional
template and to obtain the desired smoothness. Because of the variety of machine manufacturers
92
Original Date: 1/3/94
Revised Date: 05/27/16
and the various machine modifications possible, this section will deal with general inspection
procedures and methods.
506.1 VIBRATORY SCREED
When hand finishing methods as defined in the Specifications are applicable, a vibratory screed
may be used to finish pavement. The vibratory screed is basically a lightweight, nonselfpropelled finishing machine. The older versions of this machine are made with a 2 x 8 through 2
x 12 framework of wood with angle iron attached to the bottom edge of two parallel members to
form a non-oscillating screed system. The machine is further equipped with an offset weight
vibratory system powered by a small gasoline engine mounted directly to the framework. The
entire framework is either cable drawn or pulled forward by workmen. The newer vibratory
screeds are a lightweight, cable drawn, space frame truss. The screeds are parallel angle iron
running the length of the interconnecting truss sections. These truss sections are jointed by
adjustable threaded connectors which allow each section to be set at a specified cross slope.
Vibration is obtained either by a gasoline powered offset weight vibratory system or by a series
of pneumatic cylinders mounted directly to the truss and powered by compressed air.
Inspection of the vibratory screed will include the following:
(a) The vibratory screed should be ling enough to allow a minimum of one foot of screed to
ride on the side rails or adjacent pavement.
(b) The screeds should be adjusted to the desired cross slope by use of a taut sting line
applied to each screed. When a crown or break in cross slope is to be placed in the
screed, the screed should first be made straight and the machine set in place on the forms.
The crown or break in grade should then be set in the machine while supporting its total
weight on the forms.
(c) The vibration system should be checked to make sure all components are in working
order and that a minimum frequency of 3600 impulses per minute is maintained. When
pneumatic cylinders are used to provide vibration, an occasional check of each cylinder
will be necessary in order to prevent sticking of the piston. Over vibration of the surface
is to be avoided, and vibrations should be allowed only while the machine is in motion.
(d) Consolidation and strike off of the concrete will be done by labor forces in advance of the
vibratory screed. Consolidation should be performed by hand held immersion type
vibrators with a minimum frequency of 4500 impulses per minute. The strike off in
advance of the vibratory screed should leave enough concrete to allow both front and
back screeds to carry sufficient concrete to fill in all depressed areas. Occasional filling
with fresh concrete between the screeds will be necessary to accomplish this.
93
Original Date: 1/3/94
Revised Date: 05/27/16
(e) A metal straightedge and string line should be used at varying intervals behind the
screeds to check for surface smoothness and desired cross slope. Because of the
lightweight nature of the machine, it will tend to ride up over excessive concrete in the
form line. When this occurs, the paving operation must be halted and the vibratory
screed moved back beyond the bad area and rerun over the area until the proper cross
sectional area is obtained.
(f) When the vibratory screed is run partially or totally on the adjacent pavement, care must
be taken to match the existing edges. Care must also be taken to clean the adjacent
pavement to prevent the screed riding up on the rock or debris. The direct application of
weight on the outside ends of the screed is desirable to prevent these problems.
(g) Because these machines are cable drawn, care must be taken to keep the cable extended
as far as possible in front of the machine to prevent tipping forward of the screeds due to
too great an inclination angle of the pickup cable. The machine should be drawn forward
equally on each side to keep the machine as perpendicular to the forms as possible.
(h) In superelevated areas, the machine will have a tendency to migrate to the low side of the
formed area. Care must be taken to prevent the machine from slipping from the forms in
these areas. Concrete may also have a tendency to migrate to the low side and this must
be avoided or corrected immediately.
506.2 RAIL FINISHING MACHINE
This type of finishing machine is self-propelled and must be equipped with two oscillating-type
transverse screeds. Each screed is composed of self-adjustable incremental plates or enclosed
sections. These sections or plates can be adjusted to form a straight-edge, crown or other profile
shape. The finishing machine should also contain vibrators.
The following inspection procedure should be utilized prior to paving with the finishing
machine:
(a) Vibrators should be checked for frequency of impulses, side form clearance, depth of
penetration, uniformity of vibration by area and use of vibrators only when paving train is
in motion.
(b) The alignment of the two oscillating screeds must be checked prior to any paving being
performed. The alignment should also be checked each time the finishing machine is
moved from one paving site to another on the same project. Before the screeds can be
set, all concrete debris must be removed from the screed and adjusting devices. The
alignment can be accurately checked only when the machine is mounted on the forms.
94
Original Date: 1/3/94
Revised Date: 05/27/16
(c) The screeds should be checked independently and in the following manner:
(1) Place several thicknesses of lumber (2 x 2 or surveying lath) on the side forms, being
sure and equal height is used on each side. Run a string line under the back edge of
the screed and pull very taut – lower the screed onto the wood on the side forms. Be
sure the full weight of the screed rests on the wooden supports.
(2) Lower or raise each incremental plate or section until the proper typical section is
obtained. Generally, all plates should be adjusted to a point above the string line and
then adjusted down to the proper alignment. When adjustment involves a major
movement of the plate (+1/2 inch), the plate should be tapped with a 2 pound hammer
to ensure that the plate is not in a bind or blocked by concrete.
(3) The oscillation of each screed should be checked for freedom of movement. The
arms should be straight, well-greased and unimpeded by any concrete or debris. The
oscillation of each screed should carry the end well past the form line without making
the screed end opposite enter past the outside form line edge. If a shoe is attached to
the end of the screed, care should be taken to mount the bottom of the shoe so as to
pass over the top of the form without snagging.
(4) The elevation of the front screed should be such as to allow approximately 1/4 inch of
material to pass to the back screed at all times. The back screed will be set exactly on
grade. Concrete should be present in the form of a small roll in front of both screeds
at all times to fill any depressions in the pavement surface. Should either screed lose
the concrete in front of the screed edge, fresh concrete must immediately be placed or
the finishing machine stopped, backed up and concrete added to obtain the proper
section.
(d) The wheels on the carriage of the finishing machine should be checked for alignment as
stated in the spreader section. The wheels should also be checked for contact with the
form at all times. Excessive amounts of concrete in front of the screeds may cause the
machine to ride up, or if excess concrete falls over the form line, the wheels may bind up
or ride up.
(e) The final check on the accuracy of the finishing machine in providing the desired product
will be with a 10 foot wide manual straightedge applied to the finished surface of the
pavement. A cement mason should check the screeds performance as soon as possible
once paving has commenced. The straightedge should be drawn across the pavement
95
Original Date: 1/3/94
Revised Date: 05/27/16
surface, and any repetitive error in surface finish should be corrected by adjusting the
screed plate. A constant check with the manual straightedge is required to obtain a
quality pavement surface. A string line may also be used to obtain the same check for
accuracy of the screed alignment.
506.3 SUBGRADE PLANER
Often the first machine involved in a slip form paving operation is the subgrade planer. This
machine is self-propelled, track mounted and designed to cut the aggregate or dirt subgrade for
the paving operation. As this machine is designed to cut the subgrade, it will also be necessary
to make the subgrade wider than required to allow room for the travel of the slip form
equipment. Excess aggregate material from the subgrading process may be reused provided
proper compaction is obtained. As with all slip form equipment, the major area of inspection is
the contact surface of the alignment and elevation sensor with the graded string line. If both
front and rear sensors are parallel and in contact with the string line, the grade should be exact
and require only supplemental check by transverse sting line across the grade.
506.4 CONCRETE SPREADER
The next piece of equipment of the slip form paving train is the concrete spreader. The spreader
usually contains a conveyor belt used to place the concrete transversely across the paving area
and an auger or strike-off blade which will act to place the concrete to grade (+ 1/2 inch). This
piece of equipment may on occasion be waved by written approval and the concrete placed on
grade by hand methods. As with all slip form equipment, the alignment and elevation are
controlled by graded string line and automatic sensor control mounted to the equipment.
506.5 SLIP FORM PAVINIG EQUIPMENT
In recent years, the slip form method of paving has been developed and is becoming more
prevalent due to lower cost and labor requirements.
The principal point of inspection for every operation in this method of paving is the electronic
sensor string line which will establish both alignment and elevation. By using the pavement
grade stake at the indicated offset and a standard distance above grade, it is possible to establish
a parallel grade which the slip form equipment can follow while paving operations are underway.
The sting line must be set on both sides of the pavement.
Because the sensor will duplicate the string line in the pacing of pavement, it is imperative that
the following items be inspected:
(a) The string line is supported by an arm attached to a pin. The pin should be set plumb and
at a distance which will establish the string line at the required offset distance for the
96
Original Date: 1/3/94
Revised Date: 05/27/16
sensor to establish the edge of the pavement. (This distance is variable from paver to
paver but will be constant throughout each project.)
When paving adjacent to existing pavement precludes establishing vertical pins by
driving them into the shoulder, pins in weighted containers may be used. Adequate
weight will be required to prevent movement of the string line, and each pin should be
checked in advance of the paver and monitored for movement as the paver proceeds.
(b) The arm on the pin is adjustable for elevation control and should be set perpendicular to
the proposed edge of the pavement. By considering the pavement cut or fill in relation to
the operational sensor height, the parallel grade of the string line may be established. The
arm should conform to the standard shape and should be firmly mounted to the pin. The
string line should be taut from arm to arm and should rest in the slotted tip of each arm.
The slip form paver is self-propelled, track mounted and designed to spread, consolidate, shape
and finish the concrete pavement in one pass. The paver is equipped with an auger strike off
system designed to spread and consolidate the concrete into the proper shape. The vibration
system is composed either of immersion vibrators, pan or surface vibrators, tamping bars or a
combination of all methods. The vibratory system should be checked for proper frequency of
impulses. The vibration system should only be activated while the machine is in forward
motion. The surface finishing system will be composed of an oscillating transverse belt or pan
float system which will substantially complete the finishing of the pavement surface. In addition
to these specified systems, a keyway placing system is also used in conjunction with the paver.
The major items of inspection are the sensor system which follows the graded string line (as
presented earlier) and the edge slump of the finished pavement. The sensor system will
reproduce the string line for alignment and elevation. The potential for error is mainly in
improperly set string line, improperly aligned sensors, loose connections and starting the paver
(paver will tend to ride up). The edge slump of the finished pavement is controlled by the initial
slump of the concrete and the length of trailing forms attached to the paver. No slumping of the
concrete will be allowed 6 inches from the edge. No slump concrete is desirable, especially
when pouring against an adjacent slab.
Generally, both pan type and immersion type vibrators will be included in the vibration system
of the paver. Surface type pan vibrators must be operated at a frequency not less than 3600
impulses per minute, and internal type immersion vibrators must be operated at a frequency not
less than 4500 impulses per minute. Impulses may be checked with a tachometer as provided by
your Regional Project Engineer Supervisor.
The tachometer works on the principle of harmonic damping and should be used as follows:
(a) The vibrating wand in the center of the tachometer should be fully exposed.
(b) The tachometer should be placed adjacent to the vibrator head on a fixed surface and
braced against the vibration.
97
Original Date: 1/3/94
Revised Date: 05/27/16
(c) The wand should be withdrawn into the body of the tachometer until the vibration of the
wand ceases. At this point, the scale on the case of the tachometer may be read to
determine the frequency of impulses. This procedure should be repeated to obtain an
average reading.
Specific areas of vibration are the areas just adjacent to the forms and at the screed. Care should
be taken not to over vibrate the concrete (too much water coming to the top).
507 CONCRETE DELIVERY
507.1 NON-AGITATING TRUCKS
When wet mixed bathes of concrete are to be transported from an on-site batch plant in nonagitating trucks, the truck bed must be of a smooth metal, mortar tight design capable of
discharge without segregation. If discharge is tilting the bed, baffles may be required to prevent
segregation by slowing the rate of discharge. Discharge into an approved spreader at the paving
site will negate the aforementioned requirements concerning segregation. Discharge of wet
batched concrete from the batch truck must be completed within 30 minutes after mixing was
initiated at the batch plant unless a longer period is designated by the Materials Engineer because
of retarder or other additives that have been added to the mix.
507.2 TRUCK MIXED
When central and truck mixed concrete is to be used on the paving project, the proportioning will
be performed at a central plant. This proportioning will be inspected by the Materials Testing
Section.
Mixing trucks are required to have the following features:
(a) Metal Rating Plate approved by NRMCA stating maximum capacity in terms of volume.
(b) Manufacturer’s Data Plate which states the actual capacity as an agitator and maximum –
minimum mixing or agitating speed.
(c) Water measuring devices to accurately determine added water.
(d) A counter to determine revolutions of the mixing chamber.
(e) Radio communications with the central plant site.
(f) All above requirements to be verified at the plant site before loading or discharging truck
at the site.
98
Original Date: 1/3/94
Revised Date: 05/27/16
507.3 AGITATING TRUCKS
Some batch trucks are equipped with agitating augers and water supply systems. Since these
trucks are not true mixing trucks meeting all requirements of the Specifications, they should not
be allowed at any time to add water to their concrete loads.
507.4 MATERIAL
The testing schedule established in Section 1000, Materials Testing, for concrete is a minimum
testing schedule. As emphasized here and elsewhere, the testing of concrete is done mainly to
ensure that a consistent product is being produced for inclusion in the project. When it is
possible to verify a consistent slump and air content, the concrete testing should follow the
proposed testing frequency; however, until this consistency can be ensured, testing of each truck
should be performed. Rejection of material not suitable for use should only be made by the
Resident Engineer or designated representative. The Resident Engineer should order changes in
the concrete only after conferring with the Materials Engineer and/or the Materials Inspector at
the plant. Under no circumstances should mix design changes be made without the approval of
the Materials Engineer. It is imperative that the contractor’s representative be informed of the
rejection of material, the reason for rejections and remedial action to be taken as these events
take place. The contractor’s representative should be made aware that the paving procedure
cannot proceed uninterrupted until a consistent product is being presented for use. Testing will
be performed at a frequency necessary to ensure the quality of the material.
The Resident Engineer and his technical support team should have a general knowledge of the
design parameters and physical properties of the Portland cement concrete which is being
incorporated into the paving project.
A concrete mixture is designed by using the maximum water-cement ratio at which the concrete
will obtain a desired strength. (A mix of cement, sand and coarse aggregate usually supplied in
one compressive strength value of 4500 pounds per square inch.) This allows for a working
margin of error from the Department’s minimum compressive strength requirement for pavement
of 4000 pounds per square inch.
Plant inspectors who monitor the production of the concrete determine the amount of free water
contained in the coarse and fine aggregate in its natural state. This quantity of water is added to
the amount of mixing water introduced into the concrete mixture at the plant and the sum (in
gallons per cubic yard) is recorded on the first ticket as total water. The maximum amount of
water allowed by the Specifications is also recorded as maximum water in units of gallons per
cubic yard. The difference in these two numbers is the amount of water in gallons per cubic yard
that can be added to the mix, provided that all additional construction parameters are satisfied.
(Note: Never advise the contractor as to the amount of the water that he may add to the mixer.
Inform him of slump requirements of the mixture and let him make the determination on the
addition of water.)
99
Original Date: 1/3/94
Revised Date: 05/27/16
If concrete is delivered to the job in truck mixers, it is necessary for the drum to operate at
agitating speed which is between 2 and 6 revolutions per minute. If it is necessary to add water to
the load, the concrete should be mixed at mixing speed (4-12 revolutions per minute) for 30
revolutions.
In addition to monitoring the water content of the mixture, continuous attention should be given
to the following material specifications:
Air-Entrainment – Between 4.0 and 7.0 percent.
Consistency – Slump between 2 and 4 inches (3 inches maximum for slip form paving
operations).
Concrete Temperature – Shall be between 50° F and 80° F when a heated mixture is
required.
The contractor may, under certain conditions, alter the physical properties of the plastic concrete
by the use of chemical admixtures. Approval for the use of set retarders or accelerators, water
reducers or plasticizers must be granted by the Materials Engineer prior to their use.
Calculating Quantities – It is important for the inspector to know how many cubic yards of
concrete will be needed to complete the pour. This quantity can be computed by using the
following formula:
FORMULA 507.4 - CALCULATING APROX. CONCRETE VOLUME
Where
Cubic Yards = L x W x T
324
L = Length in feet
W = Width in feet
Square Yards = L x W
9
T = Thickness in inches
508 PAVING OPERATION
When all appurtenances have been placed on the subgrade and for form line checked for
alignment and elevation, the paving machine may be mounted on the forms. At this time, screed
elevation, function and straightness should be checked. All mechanical equipment should be
started and checked for proper function prior to the placing of any concrete.
508.1 PERSONNEL
In advance of the pour, arrange with your Regional Project Engineer Supervisor to have the
necessary personnel available to properly inspect the pavement pour. Ideally, three inspection
100
Original Date: 1/3/94
Revised Date: 05/27/16
personnel will be available for the pour. One inspector should be in charge of material testing,
obtaining material tickets and checking for compliance in discharging of concrete within the
allotted time periods (1-1/2 hours after batching begins, 15 minutes after discharge begins).
Non-agitating equipment used for transporting concrete must be discharged within 30 minutes
from the introduction of the mixing water. This inspector should also guide the contractor in
mixing of the concrete, checking for compliance with the water-cement ratio and number of
revolutions during mixing of added water (100 revolutions maximum). The inspector should
never advise the contractor as to the amount of additional water to be introduced into a load of
concrete. As this is a very responsible position, the best qualified inspector should be used and
should check frequently with the Resident Engineer. The second inspector should stay in front
of the paving train and assist the first inspector in performing testing procedures. The second
inspector should inspect paving accessory placement, subgrade condition and moistening,
machine operations (especially operation of the finishing machine), proper placement of joint
materials and general organization and performance of the paving operation. The third inspector
should inspect the straightedging of the pavement, float finishing, pavement texturizing and
placing of curing compound on the finished product. By properly utilizing his personnel, the
Resident Engineer can be free to oversee all phases of the paving operation.
509 PAVING PROCEDURES
When a consistent concrete product is being delivered to the project, the paving can proceed in a
normal fashion. Inspection should include the following elements:
(a) Concrete Delivery Vehicles – Under some circumstances, concrete may be discharged
from the mixer directly onto the prepared subgrade. Before this can happen, the subgrade
should be free of papers and debris, all appurtenances for joints should be in place and
secured, the subgrade should be moistened utilizing water from the mixing vehicle, the
load transfer devices should be lubricated properly and the restraining wires should be
removed. The material ticket should be properly signed by the Materials Inspector at the
concrete plant and contain time of batching, maximum amount of water per cubic yard
allowable and actually amount of water per cubic yard added at the plant. Water should
only be added to the concrete when ready to discharge, and a time check on discharge
and age of the load should be kept. Attention should be paid when haulage routes are
adjacent to the form line so that the forms are not disturbed or pumped up by subgrade
failure. Trucks which do not properly mix the concrete should be barred from the pour
by notifying the Materials Engineer. A designated wash out zone should be established
by the prime contractor and used by the concrete producer; indiscriminate wash out
points should be forbidden.
509.1 PAVEMENT DEPTH CHECK
101
Original Date: 1/3/94
Revised Date: 05/27/16
The purpose of the depth check is to verify the actual depth of pavement being placed. After the
finishing machine has completed the consolidation and finishing of the pavement, the depth
check gauge is inserted into the concrete at the designated test site. It is important to check the
pavement surface prior to taking the test and to insert the depth probe vertically. This check
should be made on a regular basis and results recorded in the Grade Book. Areas of thin
pavement should be reported to the contractor and, if necessary, the finishing machine screeds
should be adjusted. Should the contractor fail to correct the problem, your Regional Project
Engineer Supervisor should be contacted immediately and the area marked for core drilling at a
later date. As depth of concrete is a major concern, this check should be done promptly after
paving operations begin. Penalties for insufficient pavement thickness will be assessed.
509.2 BEGINNING THE POUR
The first major item of inspection after paving has commenced will also be one of the last major
items when the pacing is completed (the finished surface at the header). Obtaining a smooth ride
where paving sections abut, or will at some later time abut, requires establishing the proper cross
section of pavement at the header. Inspection of the first and last 10 feet of pavement should be
the most comprehensive inspection of the day. The header should be set to grade and checked
after the paving equipment is beyond the first form or last form. Settlement of the header is
common because of concentrated loads at the end of the form line. The concrete should be
straightedged both longitudinally and transversely before float finishing is allowed. A check by
string line will indicate the accuracy of the straightedging. Where the new pavement abuts
existing pavement, a 2 x 4 makes a better strike off than the standard straightedge. To prevent a
bump, the existing surface features must be incorporated into the new pavement and then
transitioned to the new proposed pavement section. The 2 x 4 should be extended back onto the
existing slab a minimum of 2 to 3 feet to reproduce the existing surface features.
Unless the subgrade is damp when the concrete is deposited, it will absorb water from the
concrete, and shrinkage cracks may form in the pavement. To prevent such absorption, a dry
subgrade should be sprinkled immediately before placing the concrete. Bear in mind that the
newly paced concrete must be prevented from drying out too quickly (which will seriously
reduce ultimate strength). Moist curing is essential to reach the desired strength. Pre-sprinkling
heavily the night before will afford a better condition in hot weather. This will not eliminate
sprinkling at the time of the pour.
509.3 DURING THE POUR
After the paving train has been adjusted and is producing a consistent product, inspection will
involve checking the equipment for continuity of performance, checking the concrete for
consistency, checking for faulty forms or soft subgrade and checking the finished product for
acceptability. When the equipment is performing properly, the cement masons should have to do
very little corrective work to the pavement surface. If this is not the case, the contractor’s
representative should make the necessary adjustments in the paving train in order to obtain the
best possible product. The cement masons should check each square foot of pavement for proper
cross section by using the straightedge. The straightedge should be a minimum of 10 feet in
102
Original Date: 1/3/94
Revised Date: 05/27/16
length and should be straight (a large number are not). The straightedge should be checked by a
string line drawn between the two ends and by a string line drawn across the pavement as a
check. The straightedge should bne placed on the concrete in the center of the slab and should be
frawn to the side form. The next pass of the straightedge should overlap the first pass by 5 feet.
As the straightedge is drawn to the side forms, low spots will appear as areas of discoloration and
visible daylight will be seen under the straightedge; high spots will appear as roughened areas
and will produce a roll of mortar in front of the straightedge. The straightedge is an indicator
only and should not be used to cut out high areas in the concrete surface. It will also indicate an
area requiring additional concrete to fill in low areas in the pavement surface. Checking the use
of the straightedge by using a string line will tend to point out minor mistakes and keep everyone
honest. (As a rule, cement masons will use the straightedge only when compelled to.) All
pavement should be edged at the side forms with a ½ inch radius edging tool following the
straightedging operation.
509.4 INTERRUPTION OF THE POUR
In the event of an emergency or mechanical breakdown which will stop the paving operation for
a period of more than 30 minutes, a construction joint must be installed. Any excess concrete
must be removed from the forms and, if possible, the pour should be stopped at a full joint or a
10 foot increment. A Type E joint should be used at this location. In hot weather or rain, it may
be necessary to make provisions for removal of the paving train and finishing of the paving in
advance of the 30 minute interval previously specified. Under no circumstance should the initial
set of the concrete be disturbed in an effort to complete the finishing of the paving surface due to
the failure of the contractor to act in a responsible manner.
509.5 SURFACE TEXTURE
After the pavement has been straightedged, it should be floated to produce a continuously
smooth finished surface. The finished surface should be smooth, on grade and completely
sealed, with no surface honeycomb or marring visible. As this will require a consistent effort on
the part of the cement masons, the contractor’s representative should be cautioned when the
paving train begins to leave large amounts of unfinished pavement. The paving operation should
be stopped momentarily if the unfinished pavement begins to attain its initial set without being
properly finished. The contractor’s representative is responsible for the coordination of the
paving train’s speed with the manual time required to complete the surface finishing. This
coordination is most important and must be adequately monitored to obtain the best finished
product. In most cases, the cement masons will request the use of water placed on the paved
surface to facilitate the surface finishing procedure. This practice should not be allowed except
in very hot weather and then only when the water is placed by a pressurized applicator which
produces a fine mist of the pavement surface.
After the finished surface has been allowed to lose surface moisture by evaporation but before
the initial set is obtained, the finish surface texture should be applied. The first and most
acceptable method is the wire comb. This method utilizes a tempered spring steel tined
assembly, a minimum of 10 feet in length, with tines which extend a minimum of 3 inches
103
Original Date: 1/3/94
Revised Date: 05/27/16
beyond the head. The tines are to be spaced on 1/2 inch centers and should be rigidly mounted in
the head. The head should have an adjustable swivel connection which will allow for the angle
of the tines to be changed. With prior approval, the contractor may use a shorter width, hand
operated comb for small pours. The wire broom should be placed at a centerline and frawn
lightly to the side form to produce straight depressions in the surface of the pavement. The
surface depressions in the pavement should be 1/8 to 3/16 inch in depth but should not dislodge
any aggregate in the pavement surface. The depth of the depressions may be controlled by the
angle of the tines and the speed with which the mechanism proceeds across the pavement. When
mechanical equipment is used, these conditions can be more closely controlled than when done
manually. Should the manual or mechanical broom produce undesirable results, the pavement
surface should be refloated and, after a waiting period, the surface texture application attempted
again. Surface depressions should not be overlapped and should proceed radially around curves
so that vehicular traffic will always cross the depressions at right angle to the direction of travel.
When manual methods of texturing are used, a 1 inch space should be allowed between adjacent
passes of the wire comb.
510 CURING METHODS
Under no circumstances will pavement fail to receive a curing application nor will the pavement
be left exposed for more than 1/2 hour between stages of curing or during the curing period. If
side forms are removed before 72 hours have elapsed following the completion of the paving
procedure, the edges of the pavement thus exposed will be coated with curing membrane. Hair
checking may occur if curing membrane is not applied promptly. The wind and temperature are
the two critical factors to be monitored in relation the placing the curing membrane.
When the free water has left the surface of the pavement and the placing of curing materials will
not mar the surface, one of the following methods of curing should be applied:
(a) White pigmented membrane is the most often used method of pavement curing and is the
preferred method for main line pavement. The curing membrane should be applied at a
rate of one gallon per 150 square feet, and the material should be undiluted (a common
practice) with any petroleum product. Care should be taken to ensure that the curing
material is properly stirred to suspend the solid coloration material in the vehicle. The
material should be placed in an even application which will thoroughly cover the paved
area. The wind direction should be checked when the membrane is being applied by
pressure pump methods and, if necessary, the adjacent downwind traffic may be halted
during spraying.
(b) Should hair checking develop, curing of the affected area will be by wet burlap. When
burlap is used for curing, it is wetted and placed on the hardened pavement. The burlap
is then kept wet continuously until the final curing or sealing material is placed on the
pavement. Curing material must be completely placed within 1/2 hour after the removal
104
Original Date: 1/3/94
Revised Date: 05/27/16
of the burlap. When burlap is used in combination with wetted straw, the wetted burlap
will be applied first followed by an application of wet straw a minimum of 6 inches thick.
The straw will be kept saturated for a minimum of 72 hours and then should be removed
and disposed of.
(c) Waterproof paper, polyethylene sheeting and polyethylene-burlap sheeting are used
occasionally to cure pavement, particularly during adverse weather periods. When the
pavement surface is sufficiently hard to prevent marring, the above mentioned sheets may
be applied to the top of the pavement. Sheets should be lapped 18 inches at joints and
should extend completely across the pavement and overhang the forms to allow for
placing of weights. No weights should be placed directly on the newly poured pavement.
When polyethylene sheeting is used for curing purposes, it must be white in color – not
clear or black as is often used for surface protection during rain. If polyethylene burlap
sheeting is used, the polyethylene shall be white in color and the burlap shall be
dampened thoroughly before being placed (burlap side down) on the pavement. This
curing method will be left in place for 72 hours before removal.
(d) Less frequently used methods of pavement curing involve the use of wetted mats of
cotton or jute placed on the pavement surface and kept damp for a 72 hour curing period.
511 SAWING AND SEALING JOINTS
After the pavement has been properly cured and the concrete has gained its initial set, all
contraction joints, both longitudinal and transverse, should be sawed. Joint locations must be
marked by the concrete pouring crew as the work progresses. The concrete must be set to the
point that marring of the surface will not occur from the weight of the saw. Joints will be placed
directly in the center of the load transfer device and at the edge of each pavement lane. Joints
will be cut to the depth shown on the joint detail (minimum 1-1/2 inch depth) and will be cut
straight and in sequence. Sawing will not be performed if random cracks appear at or near the
proposed joint location. Should cracking or excessive raveling in the sawed joint appear as the
joint is sawed, work will be suspended until the concrete has hardened sufficiently to allow the
sawing to continue. Joints will always be sawed at right angles to the side forms. In
intersections, joints which would intersect the form line at a skewed angle will be stopped at
approximately 3 feet from the side form and then turned to intersect the form line at right angles.
All sawed joints and expansion joints must be sealed.
Transverse contraction joints may be grooved in lieu of sawing. A suitable finishing tool must
produce a 2 inch deep by 3/8 inch wide joint (for 6 inch pavement). All joints shall be straight,
continuously uniform and neatly finished.
105
Original Date: 1/3/94
Revised Date: 05/27/16
Before the joints can be sealed, they should be clean and dry. Often pneumatic methods are used
to accomplish this chore; wind direction should be noted and excessive dust prohibited in
populated areas.
The material used to seal the joints is hot poured into the joint and is prepared for placing in a
double boiler equipped with a recirculating pump. The sealing material should not be heated
beyond the manufacturer’s recommendations or it will lose its elasticity. Material which has
been overheated must be rejected. Caution should be exercised when near the double boiler as
overheated units frequently explode and burn.
The joint should be filled from the bottom up to the top with any excess material removed. The
joint must be completely filled to the top before it is acceptable. If improperly cleaned or if wet,
the joint material will not adhere to the side wall of the joint and can be stripped out by hand.
Should this occur, the joint sealing operation should be suspended. No traffic, construction
vehicles included, will be allowed on the pavement until properly sealed.
512 OPENING TO TRAFFIC
The surface testing and pavement cores should be made prior to opening of the pavement to
traffic. As soon as possible after the pavement is completed, the riding surface should be
checked for irregularities. Areas of surface irregularities greater than 1/8 inch in 10 feet should
be marked and ground to remove the high areas. This requirement changes from time to time
and should be discussed with your Regional Project Engineer Supervisor prior to performing the
surface test.
The apparatus used to determine the irregularities in the pavement areas is of two types:
(a) The first type is a simple beam mounted between two wheels. The device is manually
propelled, equipped with 3 adjustable length scratch indicators spaced at intervals along
the span of the beam. The unit should be adjusted before each use by pulling a line tautly
from wheel to wheel and adjusting the threaded scratch indicators to the proper height
above the string line. The surface quality check should be run in each wheel lane of each
driving lane. High areas will be marked by scratches in the pavement surfaces, and areas
designated for grinding should be marked.
(b) The other type of apparatus has an automatic marking system which is activated by a
movement detection system affixed to the beam which forms the chassis of the apparatus.
This machine is also manually propelled, has some degree of steer-ability and can also
detect surface depressions in the pavement. It should also be operated in the wheel lanes
of each traffic lane on the pavement.
Cores will be scheduled to be taken from the pavement by the Materials Engineer and may or
may not be taken prior to opening to traffic. A total of 10 cores per mile in each driving lane will
106
Original Date: 1/3/94
Revised Date: 05/27/16
be required to represent a standard sample. These cores will be made at random and at any
location pinpointed by the Resident Engineer as possibly deficient. Deficient cores may require
an adjustment in compensation or removal and replacement. Cores may also be used for the
determination of compressive strength.
Before a section of pavement can be opened to traffic, the following conditions and procedures
must be met or followed:
(a) Your Regional Project Engineer Supervisor must be informed at least 5 days in advance
to arrange for a possible news release.
(b) The concrete cylinder compressive strength test for 72 hours old (minimum time)
pavement must be at least 300 pounds per square inch for light traffic only. One hundred
and twenty hour old pavement with 3500 pounds per square inch compressive strength
may be opened to all traffic. If high early strength concrete is used, a minimum
compressive strength of 3500 pounds per square inch will be required for opening.
(c) All pavement to be opened to traffic must be cleaned either by sweeping, washing or a
combination of both. All potential roadside hazards (low shoulders, utility poles, etc.)
must be addressed.
(d) A Traffic Engineer should be contacted to coordinate striping, signing and traffic signal
implementation.
(e) The contractor must provide adequate personnel and equipment to remove barricades and
safety devices.
(f) When the pavement is opened to traffic, the County Dispatcher, the Construction Office
and your immediate Regional Project Engineer Supervisor must be notified.
513 COLD WEATHER CONCRETE
513.1 TEMPERATURE
Another factor which will affect the pouring of main line pavement is temperature. Unless
otherwise approved, no pavement may be poured when the on job ambient or prepared subgrade
surface temperature is less than 40° F. Pavement may not be poured on saturated or frozen
prepared subgrade. When, by prior approval, pavement is allowed to be placed when the
temperature is below 40° F, the contractor is responsible for taking precautions to prevent
freezing of the concrete mixture.
107
Original Date: 1/3/94
Revised Date: 05/27/16
This can be done in one of the following ways:
(a) Heated mixing water.
(b) Heated aggregate (not to exceed 150° F).
(c) Heated mixer contents (not to exceed 100° F when cement is added).
Regardless of method, on job temperature of the concrete shall be between 50° F and 80° F.
When nighttime temperatures are expected to fall below freezing, the prepared subgrade can at
times be protected by covering with polyethylene sheeting.
When ambient temperatures are expected to fall to freezing or below, the pavement must be
protected for a period of 5 days and until it has attained a compressive strength of 3000 pounds
per square inch.
The following precautions are presented as a guide for protecting the pavement; however, the
contractor shall assume all risks, and any frozen concrete shall be removed and replaced at his
expense:
(a) Temperatures from 30° F to 32° F require covering with one layer of polyethylene
sheeting.
(b) Temperatures from 28° F to 30° F require covering with two layers of polyethylene
sheeting.
(c) Temperatures below 28° F require covering with two layers of polyethylene sheeting
with an intermediate layer of 6 inches of straw.
The above requirements can change from time to time and should be discussed with your
Regional Project Engineer Supervisor prior to performing any cold weather concrete work.
514 CONCRETE REPLACEMENT (MAINTENANCE) CONTRACTS
514.1 PRELIMINARY WORK PRIOR TO AWARD OF CONTRACT
The Maintenance Division will forward maps to the Construction Division showing subdivisions
and areas under consideration for a possible Concrete Replacement Program.
Each map will be used to make a drive-through preliminary count of deficient concrete
pavement, paved approaches and sidewalks for possible replacement.
108
Original Date: 1/3/94
Revised Date: 05/27/16
After the preliminary counts are completed, the maps will be forwarded to the Maintenance
Division for evaluation. Maintenance will determine from the funds available, based on the
preliminary estimate, which subdivision streets will be included in the replacement program.
Maps of the subdivisions selected for the replacement program will be returned to the
Construction Division for final measurement. All sections of concrete pavement, paved
approaches and sidewalks will be measured to obtain square yards of removal and replacement.
For future reference, small paint marks will be placed on the tops of the concrete curbs and
around the perimeter of the pavement to be replaced. No paint marks will be placed on paved
approaches and sidewalks at this time. The total measurements of all items for replacement will
be returned to Maintenance so that the replacement contract can be finalized.
514.2 PRE-CONSTRUCTION CONFERENCE
After the award of the contract, a PRE-Construction Conference will be scheduled. Attending
will be representatives of all utilities, local government officials (municipalities), contractor,
Utility Coordinator, Regional Project Engineer Supervisor and the Resident Engineer. The
meeting is conducted by the Engineer of Construction.
The utilities will receive maps of the contract area so they can indicate their facilities in the field
in relation to the areas of replacement. The terms of the contract will be discussed with the
contractor in regard to possible disposal areas, bar chart, erosion control, etc. as defined in the
Special Provisions of the contract. A date for the work to proceed will be agreed upon.
514.3 CONSTRUCTION PROCEDURES
The contractor will designate the area where work will commence. The Resident Engineer and
Inspectors will then mark the concrete pavement, paved approaches and sidewalks with arrows
indicating the limits of removal. This advance marking should be limited, otherwise the marking
may generate citizen complaints (i.e., ‘Why is my neighbor getting a new slab and I am not?”.
Deteriorated concrete pavement, paved approaches and sidewalks will be removed and disposed
of a approved dump sites. Dump sites will be requested in writing by the contractor and will be
inspected and approved.
After the concrete pavement is removed, metal forms will be placed at the curb line and at the
centerline in the overbreak area if the adjoining pavement is to be replaced. Form lines will be
checked with a string line to assure proper alignment and grade. Generally, forms are steel of 6,
8 or 9 inches in height with a length of 10 feet. Wood forms may be used to complete the form
line if less than 10 feet. Wood forms may also be used in radii where a smooth transition is
required.
The subgrade will be prepared by spreading a variable thickness of aggregate to attain the
desired surface. Aggregate is used to fill the area between the subgrade and the bottom of the
slab. Any undermining encountered is also filled with granular material. Excessive overdigging
109
Original Date: 1/3/94
Revised Date: 05/27/16
which must be replaced with rock is not the intent of the contract, and the contractor should be
advised that he will not be paid for the excessive expense caused by his poor workmanship.
Generally, subgrade aggregate is spread by a tractor equipped with front bucket and back blade.
Some handwork may be required before final rolling. The grade is checked by string line. Final
rolling and compaction may be accomplished with a 1 ton vibrator steel wheel roller or
equivalent. If unstable subgrade areas are encountered during rolling, they will be excavated and
replaced with aggregate and recompacted.
Paved approaches and sidewalks are prepared in a like manner as concrete pavement. Generally,
grading will be done by hand. Six inch steel forms are utilized in the approaches and 4 inch steel
forms are utilized for sidewalks. Wood forms may be incorporated where needed. When
forming the sidewalk through an approach, the 5 feet of sidewalk adjacent to each side of the
approach will be graded to a depth of 6 inches. Compaction will be attained by use of a
vibratory plate compactor.
Prior to pouring concrete pavement, keyway and bent bars will be placed along the forms at the
centerline where the overbreak exists. If a concrete pour cannot be completed, a bulkhead will
be installed. Bulkheads will be placed not less than 10 feet from a joint. All forms are to be
oiled prior to placing concrete. Where a single section of concrete pavement is struck off by
using a wood or metal straightedge, the concrete will be vibrated by using a handheld vibrator.
Care is to be taken to ensure proper vibrating along form lines where keyways exist. When long
pours are necessary, a vibratory screed will be required. The screed will rest on top of the curb
form and on the existing concrete pavement or form line at the center of the street.
Prior to the use of the screed, a string line will be placed along the bottom rail of the screed to
check for proper alignment. After checking the alignment, the screed will be oiled. Concrete
will be discharged from the truck in front of the screed and hand placed along the screed as it
travels the form line. Cement masons using floats, hand floats and edgers will work behind the
screed to attain the prescribed finish. After the concrete has set sufficiently, the surface will be
textured, and curing compound will be sprayed on the pavement.
Concrete for approaches and sidewalks may be placed and spread manually. Expansion material
will be placed along the back of curb where the approach joins it. Expansion material in
sidewalk will be placed either against adjoining existing sidewalk or at 20 foot intervals in the
poured sections. The finishing techniques are the same as for concrete pavement, with the
exception of the curing compound, which does not have to be a white pigmented type.
514.4 CLOSURE OF PAVEMENT SLABS
Normally, the closure of pavement slabs for removal and replacement shall be limited to a
maximum of 5 days with 3 days of curing inclusive in this closure time. The closure of any
residential drive approach shall not exceed 5 days which shall include, at a minimum, 24 hours
curing. Due to unforeseen circumstances encountered during construction, these closures may be
extended by approval of the Residential Engineer.
110
Original Date: 1/3/94
Revised Date: 05/27/16
514.5 SIGNS, BARRICADES AND FLAGGER
When concrete pavement, paved approaches or sidewalks have been removed, and prior to their
replacement, reflectorized barricades or channelizers must be placed for protection. These
barricades, placed at overbreaks and along the center of the street at 20 feet intervals, will be
stabilized with sandbags placed on the lower part of the barricade and remain in place during the
curing period and/or until the overbreak is poured. Barricades placed along the gutter and where
approaches and sidewalks are to be poured do not require sandbags. When concrete pavement
has cured sufficiently to be opened for traffic, barricades will be positioned on top of the curb
until the area behind the curb is backfilled.
Informational signing (“Road Construction Ahead,” “One Lane Road Ahead,” “Road Work
Ahead,” “Flagger Ahead,” etc.) will be placed at the entrances of all subdivisions to inform
motorists of operations within the area. These signs will require multiple sandbags on their bases
to secure them.
The contractor’s labor force is instructed to assist motorists when they approach an area where
dump trucks or concrete trucks are blocking a lane.
514.6 INSPECTORS’ WORKSHEETS
Each Inspector will fill out a Daily Worksheet which includes the contractor’s work forces and
equipment, the individual sites of concrete pavement, paved approaches and sidewalk pours with
corresponding addresses and square yards poured. Events (broken utility lines, accidents,
property damage, resident inquiries, etc.) will also be recorded on the Worksheet for the Resident
Engineer Diary.
514.7 BACKFILL
The area adjacent to the back of curb, around paved approaches and along sidewalks will be
backfilled within 15 days. Any debris such as wood stakes, wood forms, tree branches, trash,
broken concrete or aggregate will be removed prior to placing backfill. The contractor shall not
be paid for concrete that is poured until the backfill is completed satisfactorily.
514.8 JOINT SEALING MATERIAL
The sealing material shall not be placed on wet or unclean pavement joints. The Specifications
or Special Provisions shall be referred to for the type of material and method of applications.
514.9 RESIDENT ENGINEER’S DUTIES
In order to administer the project, the Resident Engineer will be required to:
111
Original Date: 1/3/94
Revised Date: 05/27/16
(a) Oversee and assist the inspectors in their duties. Coordinate work with the contractor’s
representatives.
(b) Keep a Daily Diary of work performed; diaries for quantities will also be required.
(c) A Weekly Progress Report is required at the Construction Office on Monday, signed by
the contractor or his designated representative.
(d) Submit a semi-monthly payment estimate to the Construction Office on the 16th and/or
1st of each month
(e) Inform the Materials Testing Laboratory no later than 2:30 P.M. of the contractor’s
material needs for the next day (so inspection can be provided).
(f) Meet with residents to discuss complaints or answer questions concerning proposed
work. He will also meet daily with the Regional Project Engineer Supervisor to keep him
informed or to advise him of any problem encountered or any anticipated changes to the
contract.
(g) Be responsible for handing out notification packets to each resident of the subdivision
prior to the commencement of work on that street.
The Resident Engineer must realize that construction parameters for concrete replacement
projects continue to change. The contract’s Special Provisions should be reviewed carefully, and
modifications to the program shall be discussed with your inspection team.
515 CHECK LIST – RIGID PAVEMENT
ENGINEER AND CONTRACTOR
(a) Engineer and his inspectors hold a preliminary conference with the appropriate
contractor personnel.
(b) Continuity of operations planned.
(c) Determine number of trucks to be used.
(d) It is understood who is to issue and who is to receive instructions.
(e) Method of handling traffic established.
COMPACTION OF FOUNDATION
(a) Condition of the subgrade checked.
112
Original Date: 1/3/94
Revised Date: 05/27/16
(b) Subgrade rolled.
(c) Section has been checked and recorded.
(d) Subgrade moistened.
PAVING ACCESSORIES
(a)
(b)
(c)
(d)
(e)
(f)
Dowel supporting assemblies (approved type).
Dowels securely fastened at proper location.
Dowels properly greased and wire removed from baskets.
Longitudinal dowels properly installed and/or supported and secured.
Existing keyways cleaned.
Dowel bars for curbs.
INCIDENTAL TOOLS
(a)
(b)
(c)
(d)
Incidental tools comply with Specifications.
Straightedge checked.
Side edge have proper radius.
Plastic or other material for cover in emergencies.
FINAL ALIGNMENT AND GRADE
(a) Grade and alignment forms.
(b) Grade and alignment of string line.
(c) Any obstruction (side clearance been checked for obstructions).
FINISHING MACHINE
(a)
(b)
(c)
(d)
(e)
(f)
Sides vibrated along forms.
Tube or pan type vibrators working properly.
Concrete in front of screeds rolling, not sliding.
Check roll in front and rear screeds.
Surface texture of concrete behind finishing machine.
Measure depth of slab behind machine.
HAND FINISHING
(a)
(b)
(c)
(d)
Draw straightedge.
Hand floats.
Final crown in surface checked.
Joints and sides edged.
113
Original Date: 1/3/94
Revised Date: 05/27/16
(e) Texture of surface.
(f) Station numbers stenciled (even numbers on left hand side).
CURING
(a) Agent applied as soon as water sheen disappears from surface.
(b) Apply curing material to sides when forms are pulled.
(c) Rate of application checked and recorded.
SAWING, CLEANING AND FILLING JOINTS
(a)
(b)
(c)
(d)
(e)
(f)
(g)
Proper timing.
Sawing control joints.
Proper depth and width.
Sawed all the way to edge.
Cleaned on completion of sawing.
Fill joints as soon as joints are dry to prevent recleaning.
Joints filled flush with approved sealer.
FINAL STRAIGHTEDGING
(a) Record high spots and advise foreman.
(b) Check elimination of high spots.
HAULING EQUIPMENT
(a) Counter working.
(b) Water measuring device.
(c) Concrete placed evenly over subgrade.
TESTING
(a) Any water added on job site recorded on ticket (mixing revolutions of drum
monitored).
(b) Time checked from loading to discharge (discharge time monitored).
(c) Air tests made and recorded.
(d) Slump tests made and recorded.
(e) Cylinders cast (extra if early break requested).
(f) Temperature of concrete checked.
(g) Air temperature recorded.
114
Original Date: 1/3/94
Revised Date: 05/27/16
SECTION 600
DRAINAGE CONSTRUCTION
601 GENERAL
All storm, sanitary or combined sewer within the original and annexed Metropolitan St. Louis
Sewer District (MSD) will be built to MSD specifications and inspected by an MSD inspector.
The plans will have a “P” number on them, and an MSD permit will be required before the
contactor can start work on any sewer construction. Grate inlets, grated trough and cross road
culverts without a structure (not an enclosed system) are not inspected or maintained by MSD.
MSD inspectors inspect only the pipe and the pipe bedding but do not inspect the trench backfill.
Most often, the MSD inspector will not be able to inspect full time due to his work load;
therefore, the pipe placement will have to be inspected by County forces.
Storm and sanitary sewer beyond the annexed area will be specified as to County, private or
MSD specifications.
601.1 RIGHT-OF-WAY EASEMENTS
All construction projects will be constructed in easements, public right-of-way or temporary
construction licenses (TCL). No working room will be available outside the limits of easements
or right-of-way unless otherwise stated in the plans, Specifications, or Special Provisions.
602 CONSTRUCTION STAKING
The purpose of sewer stakes is to provide alignment and elevation control for the installation of
sanitary and storm pipe runs and structures along these pipe runs. When tying into an existing
sewer line or storm line, the line must be exposed to verify elevation, size and location before the
new line can be staked. A cut sheet (computed by the Survey Party Chief and checked by the
Resident Engineer) must be furnished to the MSD inspector. A sample cut sheet is included in
Section 1200. The typical sewer stakes will show information as shown in Illustration 602.
The staking required for the laser method requires wooden hubs offset a known distance from the
center of the pipe run. A cut distance from the wooden hub to the flow line elevation of the pipe
at a specific location is also marked on the stake. These elevations will be given at each structure
and at intervals along the pipe run. The basic principle involved is to establish a line parallel to
the flow line of the pipe run at a known distance above the flow line. It is then possible to
measure from the hub to the flow line in order to install the sewer pipe on grade. Alignment is
controlled by maintaining a parallel distance from the offset hubs. The sewer stakes will include
an offset distance, station and a cut distance to the flow line.
115
Original Date: 1/3/94
Revised Date: 05/27/16
ILLUSTRATION 602 – TYPICAL SEWER STAKING
602.1 LASER METHOD
There are two basic methods of sewer pipe installation – batter boards and laser. The method
currently employed by most contractors is the laser method. In this method, the basic procedure
is to erect the laser at a given elevation at the center of the initial structure. The laser is then
elevated to the given percentage of grade and the beam of light produced by the laser generates a
line parallel to the flow line of the pipe.
In order to double check the accuracy of the construction stake as placed, the following should
be inspected:
(a) A general check of all stakes should be made to determine if the hub and stakes have
been vandalized or tampered with.\
(b) A review of the sewer sheets in the plans will disclose flow line information at structure,
percentage of slopes on sewer runs, total length of pipe run and finished top grade of
structures.
(c) A visual inspection of plan cut at structures (existing ground line vs. proposed flow line)
versus cut shown on stake.
(d) The laser height should be double checked to determine a correct height for the produced
parallel grade line.
(e) The laser mounting post should be plumb and soundly set on line as determined by offset
stakes.
116
Original Date: 1/3/94
Revised Date: 05/27/16
(f) The correct elevation of the laser beam above the flow line must be determined and set,
and the correct slope must be set into the beam projection system. A small angular
mistake can produce a major error if not detected.
(g) Grade and alignment checks should be made at half grade hubs and as often as possible.
Again, dirt subgrade, rock subgrade and flow line grade can be checked for each joint of
pipe placed.
(h) All pipe will be laid with the bell or hub upstream of the spigot. Care should be taken to
positively support the ends of the pipe projecting through the proposed sidewalls of all
structures at the incoming and outfall points until the structure floor and invert are poured
in placed.
602.2 STRUCTURES
The staking required for structures on storm lines will include inlets, sills, manholes, and flared
end sections.
Upon completion of the pipe laying process, the inlet will again have to be staked to ensure
proper alignment of the sill. Only the sill of the main barrel will be staked (as shown in
Illustration 602.2(a) where double, triple or multiple inlets are to be built.
(a) Inlets will be staked during the pipe laying operation.
(1) A stake and hub with cut (as shown in Illustration 602) will be set at the center of the
inlet.
(2) A stake and hub will be set on a line perpendicular to the sill of the inlet and at
intervals of 10 feet off and 20 feet off. These two stakes will serve to define the center
of the inlet so that the inlet bottom can be poured after excavation has been
completed.
(b) The sill will be staked as follows:
(1) The center of the main barrel will be reestablished and marked.
(2) The new grade to the finished top grade of the inlet will be marked in the outgoing
pipe flow line
(3) A hub will be set in line with the sill of the structure and the offset (usually 10 feet)
marked on each side of the inlet.
(4) A cut or fill will be established for the hub on each side of the structure that will
provide the proper slope for the sill and top stone of the inlet. The sill should always
117
Original Date: 1/3/94
Revised Date: 05/27/16
be on the same slope as the adjacent centerline of roadway; the only exception being
a low point inlet where the sill and top stone will be set level. The “face stakes”
should always establish the top of stone at the face of stone.
(5) Auxiliary units should always be constructed upstream of the main barrel and
maintain the same alignment for sill and stone as in the main barrel.
(6) Where inlets are built on a skew, the same staking procedure will apply. The face and
offset stakes should be marked skewed to avoid confusion.
(7) For area inlets, the longest intake sill should be staked. Reference to the number of
sides open should be shown on the stakes to eliminate confusion.
ILLUSTRATION 602.2A – TYPICAL INLET STAKING
(c) Upon completion of the pipe laying procedure, the staking for manholes should be as
follows:
(1) The center of the manhole should be reestablished and marked.
118
Original Date: 1/3/94
Revised Date: 05/27/16
(2) The new grade to the finished top grade of the manhole will be marked in the
outgoing pipe flow line.
(3) A hub and stake with cut or fill to finished top grade will be set on a stated offset. The
grade shown will be to the center of the cover. The frame should be checked for
proper cross slope when placed.
(d) Flared end sections will be staked (as shown in Illustration 602.2(b) in accordance with
the following procedure:
(1) Offset stakes will be placed on each side of the flared end section at the upstream end
of the flared end section. The closet of these stakes on each side will be graded with
the proposed flow line grade. A centerline of pipe stake is helpful in obtaining proper
alignment.
ILLUSTRATION 602.2B – TYPICAL FLARED END SECTION STAKING
603 MATERIALS
603.1 PIPE
119
Original Date: 1/3/94
Revised Date: 05/27/16
The material used in the installation of storm and sanitary sewers will be randomly inspected by
the Materials Laboratory Personnel. After it has arrived on the project, it should be inspected by
the Resident Engineer and the MSD inspector and accepted or rejected at that time. Those sewer
items which are accepted by the manufacturer’s certification or independent test results should
not be placed until such requirements are on file at the Project Office.
Concrete sewer items such as reinforced concrete pipe, concrete pipe and flared end sections
may be rejected in the field for the following:
(a) Cracks or fractures which pass through the wall of the pipe except for a single end crack
that does not exceed the depth of the joint. Particular attention should be paid to
circumferential cracks which develop after the pipe has been unloaded and allowed to sit
for several days.
(b) Surface defects such as honeycombed texture and/or defects which indicate imperfect
proportioning, mixing or molding.
(c) Damaged or unsatisfactorily manufactured end which would prevent a satisfactory joint.
(d) Strength class below that designated by the plans or Specifications.
Rejected pipe sections should be clearly marked with either paint or kiel. These rejected pipe
sections may be used for cut pieces or stub out from structures provided the unsatisfactory
portion of the pipe is removed.
603.2 JOINT SEALING (WITH MSD APPROVAL)
Material used as a joint sealant should be pliable and free from any deleterious material. In cold
weather, care should be taken in warming the sealant so as not to destroy the elasticity of the
material. Some types of sealant are prepared in a summer and winter consistency for ease of
application. Joint sealant should be placed on the spigot in such a quantity that will guarantee a
completely watertight joint around the circumference of the pipe. The outside of the pipe should
also be wiped with joint sealant to ensure a watertight joint. On those pipes which have a lift
hole, a suitable plug of concrete as supplied by the pipe manufacturer should be sealed in place
with the same joint sealant as used at the joint. Care should be taken to ensure that the plug does
not extend beyond the wall of the pipe into the inside radius.
603.3 GASKET JOINTS (MSD TYPE A THRU D)
When slip-on joints, mechanical push joints or other gasket joints are used, care should be taken
to ensure that the gasket is properly installed, straight and that contacts on all surfaces are watertight. A commercial lubricant may be used to aid in compression of the gasket at the joint.
604 EXCAVATION
120
Original Date: 1/3/94
Revised Date: 05/27/16
The contractor shall proceed with caution in any excavation and shall use every means to
determine the exact location of underground structures, pipe lines, conduits, etc., prior to
excavation in their immediate vicinity. When there is reason to believe that a utility conflict may
exist, the contractor shall determine the plan and elevation location of the suspected utility in
conflict prior to commencing work on reaches adjacent to the reach in which the utility conflict
may occur. This will enable the Resident Engineer to evaluate field adjustments of lines or grade
to avoid potential conflicts. This field verification of utility locations shall be accomplished at no
additional cost and is the total responsibility of the contractor.
604.1 EXISTING UTILITIES
During the excavation for each pipe run, all existing utilities should be exposed and checked for
possible conflict due to elevation. When crossing existing sanitary lines, a check of elevation
below grade should be made to determine if encasement is required (2 feet of separation
minimum).
When a connection to an existing pipe or structure is to be made, the existing facility should be
exposed first to determine if the proposed connection is possible. When exposure is not possible
at the exact site of connection, a grade above and below the point should be obtained and an
elevation interpolated for the point as a check on the plan grade.
604.2 BRACING AND SHORING
The contractor shall furnish, place and maintain such sheeting, bracing, shoring, etc. as necessary
or as may be required to support the sides of the excavation to protect workmen in the trench or
channel and to prevent any earth movement which might in any way impair or delay the work,
change the required width of the excavation or endanger adjacent pavement, utilities, sewers,
buildings or other structures above or below the ground surface. Walers and other bracing shall
be designed and installed so there are no obstructions to proper placement of the pipe, bedding,
cradle or encasement; nor shall they interfere with the satisfactory laying and jointing of the pipe.
Sheeting, bracing and shoring shall be withdrawn and removed as the backfill is being placed
except there the Special Provisions provide sheeting, bracing or shoring to be left in place.
Where the Resident Engineer permits the same to be left in place at the contractor’s request, the
contractor must cut off any such sheeting at least two feet below the surface and shall remove the
cut off material from the excavation.
All sheeting, bracing and shoring which is not left in place under the foregoing provisions shall
be removed in a manner that will not endanger the completed work or other structures, utilities,
sewers or property whether public or private.
604.3 ROCK CUT
When pipe is to be placed in a rock cut, a minimum of 4 inches of bedding material shall be
placed to support the pipe. Six inches of bedding are required for pipe 60 inches in diameter and
121
Original Date: 1/3/94
Revised Date: 05/27/16
greater. Trench bottoms in rock shall be excavated to a depth below the outer pipe bottom as
shown on the pipe details. The contractor may use explosives as long as he complies with all
laws, rules and regulations of the Federal, State and local municipalities. If rock is encountered
in the trench, there may be a pay item in the contract; otherwise it is covered in the
Specifications.
604.4 UNSTABLE AREAS
Unstable areas in pipe trenches will be removed and backfilled to provide a firm foundation
before any pipe is laid. The contractor is also responsible for pumping any water from the pipe
trench and for maintaining a suitable foundation regardless of seepage or surrounding drainage
conditions. Any material excavated that is not used for refilling the trench should be removed
from the site and disposed of by the contractor at his expense.
604.5 TRENCH WIDTH
While excavation on the line is being made, the proper width must be maintained. The proper
trench width is considered to be the outside pipe diameter plus 4 inches on each side of the pipe.
This is a minimum width and is necessary to allow proper support to the haunches of the pipe.
When rock is encountered or cradle or encasement concrete is to be used to support the pipe, a
minimum pay width will be established for each size of pipe. In general, pay widths will exceed
the minimum proper trench width. A table of trench pay widths will be contained in the Standard
Drawings or in the “MSD Standard Construction Specifications.”
Sidewalls of the pipe trenches should be as vertical as safety considerations will permit. This
may not be possible in unstable ground or extremely deep trenches but, when possible, sidewalls
should be kept vertical and straight. These measures will ensure uniform compaction of backfill
materials and stable support to the adjacent soil. The protecting of all pipes, conduits, culverts,
ducts, utility poles, wires, fences, building and other public and private property adjacent to or in
line of work is included in the contract unit price for pipe in place.
604.6 TRENCH LENGTH
The length of trench which may be opened in advance of the completed sewer shall be limited to
200 feet, except with permission of the Resident Engineer. In rock, the length shall be sufficient
to protect the completed cover. The contractor is responsible for the protection of all open
excavation made by his operation.
604.7 INSPECTION OF EXCAVATION
Excavation for storm and sanitary sewer runs will involve inspection of the following items:
122
Original Date: 1/3/94
Revised Date: 05/27/16
(a) Alignment – The alignment of each sewer run will be established from the sewer stakes
set by the Survey Party. The offset distance at right angles from each hub will provide a
point at the center of the pipe.
In most cases the contractor should provide a painted line from point to point to provide
the operator with a reference while digging the trench. In all cases, an occasional check
on alignment should be made to ensure a pipe run true to line.
(b) Elevation – Elevation control will be established by the Survey Party and will establish
the flow line of the pipe at a point at right angles to the hub. Excavation to proper depth
will require an allowance for bedding thickness and shell thickness of the pipe below the
established flow line elevation.
Shell thickness of various pipes can be found in the Specifications. Elevation is
controlled by either batter boards or laser using a line established as parallel with the
proposed flow line of the pipe run.
605 PIPE BEDDING
The plans and Specification shall indicate the specific type or types of bedding, cradling, or
encasement required in various parts of the sanitary sewer construction if different than current
“MSD Standard Construction Specifications.” Granular backfill shall be required in all trench
excavation within public (or private) street right-of-way or areas where a street right-of-way is
anticipated. Special provisions shall be made for pipes laid under or over fills or embankments in
shallow or partial trenches either by specifying extra strength pipe for the additional loads due to
differential settlement or by special construction methods to prevent or to minimize such
additional loads.
Inspection will involve the following:
(a) Adequate trench width to ensure passage of backfilling and bedding material around the
circumference of the pipe.
(b) Excavating and forming the bedding to correspond to the shape of the pipe to be laid.
(c) Placing bedding to proper side height of pipe being placed and for length required.
Class C Bedding consists of two very distinct types of construction procedures and material
requirements. MSD specifies crushed limestone and screenings only.
(a) When crushed rock and screenings are used as Class C Bedding, a minimum of 4 inches
should be placed under the pipe and shaped to support the pipe for its entire length not
just at the bell spigot connection. The Specifications provide gradation for two types of
rock bedding based on pipe size (inside diameter). A 6 inch minimum bedding is required
for 60 inch diameter and larger reinforced concrete pipe.
123
Original Date: 1/3/94
Revised Date: 05/27/16
The bedding should extend the full width of the trench and be continuous for the full length of
the pipe run.
When MSD specifications govern the work in progress, the following items should be inspected:
(a) All pipe, except reinforced concrete pipe, is required to be placed on bedding which will
extend to a height of 6 inches above the pipe. The gradation of the bedding is dependent
on nominal inside pipe diameter with all pipe 27 inches or smaller being bedded on MSD
1 and all pipe 30 inches in diameter or larger bedded on MSD 2. MSD 1 and MSD 2 are
not the same gradation as specified for County bedding but are used interchangeably.
(b) Reinforced concrete pipe will be bedded on MSD 1 or MSD 2 as size dictates. The
bedding will extend to the spring line in height for the entire pipe run.
(c) All MSD bedding will have a minimum thickness of 4 inches and a minimum width of 4
inches wider than the outside of the pipe diameter on each side.
606 EXCESSIVE GRADES
606.1 CONCRETE CRADLE
Bedding used for pipe may be of several types denoted as follows:
Class A Bedding involves the use of concrete cradle to hold the pipe in place. Concrete cradle is
used mainly with excessive grades. When the grade of a sewer is between 25 to 50 percent, a
concrete cradle or collar is required. For grades exceeding 50 percent, a special design and
specification will be required.
Inspection involves:
(a) Use of proper concrete (Class A).
(b) Proper means of support for the pipe while concrete is being placed under and alongside
pipe (concrete bricks or blocks).
(c) Proper thickness of cradle under pipe (4 inch minimum – MSD, ¼ internal diameter
otherwise) and minimum width of cradle (4 inches beyond outside pipe diameter – MSD,
6 inch beyond outside diameter otherwise) and minimum height along pipe (spring line –
MSD, ¼ outside diameter otherwise).
(d) Opening of joints or sliding of pipe sections which displace or misalign pipe. (Note: Use
of vibrators shall not be permitted; concrete should be puddled and pushed under pipe).
124
Original Date: 1/3/94
Revised Date: 05/27/16
(e) For County Type 3 Step Cradle, individual level plateaus must be a minimum of 2 feet in
length with a minimum bedding of 4 inches at the nearest point (6 inches of concrete for
pipe 60 inches and larger).
For ease of placement, a bulkhead should be constructed at the downstream end of pipe and
concrete poured uphill. Low slump, Class A, hand placed concrete is recommended. Backfill
materials may not be placed above the concrete until it attains its initial set.
606.2 BEDDING FOR EXCESSIVE GRADE (CAP)
Excavation and Laying of Corrugated Aluminum Pipe (CAP):
(a) Subgrade and backfill around CAP should be select and mechanically tamped dirt
backfill.
(b) Concrete should be placed on each side of flange to serve as both an anchor to hold the
flange in place and to seal the joint where the two pipe join together. Concrete is to reach
to the top of diaphragm on downstream side only.
(c) The perpendicular trench for diaphragm should be cut into undisturbed earth only. It
should be one foot wide and as long as the diaphragm is beneath the pipe.
(d) Structures joint to this pipe should have extra thick (10 inch) bottoms with tapered inverts
to provide smooth flow of drainage with no angular flat spots through bottom.
607 PIPE PLACEMENT
Pipe used in sewer construction will normally be Reinforced Concrete Pipe (RCP), Vitrified Clay
Pipe (VCP), Polyvinyl Chloride Pipe, Ductile Iron Pipe and Corrugated Metal Pipe (CMP). The
jointing of the pipe and the materials used are determined by the type of pipe used.
Joint types shall be designated on the Construction Drawings.
Care should be taken when placing each section of pipe to obtain a tight joint at the spigot-bell
connection. This is best obtained by placing the upstream pipe utilizing a “pinch bar” to force the
two pipe sections together. For straight alignment, the following maximum joint widths are
allowed inside the pipe:
12 to 21 inches diameter – ¾ inch
24 to 45 inches diameter – 1 inch
48 inches & larger diameter – 1–¼ inch
For radius pipe, a 50 percent increase in these maximum tolerances will be allowed. Regardless
of pipe class or type, the flow line should provide a straight, continuously uniform surface – this
125
Original Date: 1/3/94
Revised Date: 05/27/16
requirement should be checked several times during the placing of each pipe run. When pipe is
to be laid on a flat grade (1 percent or less), each pipe section should be checked with a 4 foot
carpenter’s level to ensure fall in each pipe placed. Under no circumstance should any pipe be
laid level. Minimum grade on normal sized pipe should not be less than 1 percent; however,
MSD will allow grades of less than 1 percent for some sanitary lines or extremely large diameter
pipe runs.
After the pipe is in place in the trench and is at the proper elevation, alignment should be
checked. This is best done when at least 3 joints of pipe have been laid but not backfilled.
Alignment should be by eye with applicable distance from offset stakes checked when possible.
As previously stated, the straight, continuously graded appearance of the flowline is the most
important consideration in placing of sewer pipe.
Before any backfill is placed, the pipe lift hole plugs should be placed and the exterior surface of
the bell-spigot joint sealed with joint sealant.
Backfill may then be placed as required with care being taken to fill around the haunches of the
pipe (by hand if necessary) to lock the pipe run in place.
Inlet and outlet pipes shall extend through the wall of the structure and shall be cut off flush with
the inside surface of the wall.
607.1 UTILITY CONFLICT DURING SEWER INSTALLATION
Conflict in elevation or alignment with existing utilities during sewer installation will occur on
almost every project.
Prior to the commencement of actual construction, field surveys of the pipe runs and structure
locations should be made. Utilities shown on the plans should have had actual elevations shot
during the design phase. Undiscovered utilities, not found until the construction begins, should
be immediately shot to determine location and elevation and cross checked to see if a possible
conflict does exist with the proposed work. Conflicts due to alignment may be corrected by
redirecting sewer runs via installed manholes, increase or decrease in pipe run depth or utility
relocation to avoid the conflict. When observed in advance of the proposed construction, the
changes may be accomplished with minimum quantity changes and loss of time. A Change
Order should normally be prepared for your Regional Project Engineer Supervisor along with a
sketch of the proposed corrective action. Minor changes may be accomplished on verbal
permission while major changes may require a redesign of the system with approval from other
agencies required (MSD or the utility company). Always notify your Regional Project Engineer
Supervisor with any conflicts. Conflicts due to elevation usually occur during the actual
construction procedure. When they occur, it is very important to establish accurate elevation of
the flow line of the proposed pipe at point of conflict and the elevation and diameter size of the
utility in conflict. Ongoing work should be suspended until this determination of elevation can be
made.
126
Original Date: 1/3/94
Revised Date: 05/27/16
Notify your Regional Project Engineer Supervisor of your problem and of your proposed
corrective action. When the amount of conflict is determined from the outside of the proposed
sewer pipe to the outside of the conflicting utility (plus an allowance for a bedding cushion
between the pipes), a correction by changing the slope of the sewer may be contemplated.
Because pipe is laid upgrade, it is usually possible to drip back in the pipe run and alter the
proposed slope to clear above or under the conflict. It is necessary to review the effect on the
hydraulics of the pipe run before proceeding with a slope change. Always wait for approval
before such changes are made. A small uncomplicated change may be verbally approved and
there may not be any additional cost to the County; however, changes involving addition of
structures, redirection of the sewer run to gain elevation differentiation or major increase or
decrease in flow line slope will require a Change Order, redesign and redesign approval. When
this is clearly the outcome of the conflict, the contractor should be notified to suspend operations
on this and adjacent pipe runs until such time as an approved course of action is determined.
Always bear in mind that the normal minimum approval pipe slope is 1 percent. Pipes should not
rest upon one another; a slight (1 to 3 inch) separation is desirable for bedding. Sanitary crossing
with less than 2 feet vertical separation require encasement. The desire to obtain a quick solution
to a temporary suspension of work will cause you to make simple mistakes in arithmetic. Always
have your computations double checked.
607.2 CONCRETE ENCASEMENT
Concrete encasement is required when pipe runs will have insufficient cover to cushion the pipe
or when one pipe may bear on a lower pipe either in parallel or crossing trench. MSD requires
that all pipe with less than 3 feet of cover be encased. Also MSD requires encasement of VCP
sewers when crossing pipe runs have less than 2 feet of separation.
When a storm pipe crosses over a sanitary sewer and the vertical clearance is less than 2 feet, the
sanitary sewer must be encased in concrete for 20 lineal feet or 10 feet each side of the crossing.
Inspection involves:
(a) Establishment of encasement limits, including location of existing sanitary sewers.
(b) Proper blocking and support of each pipe section to allow free passage of concrete under
and around pipe to be encased.
(c) Proper material in the form of concrete (Class C- County, Class A – MSD).
(d) Minimum encasement of 6 inches of concrete completely around pipe on all faces.
When VCP is being placed, the following items should be checked:
(a) Proper pipe strength. Standard strength may be used unless extra strength is specified or
pipe is placed under driving surface when extra strength is required.
127
Original Date: 1/3/94
Revised Date: 05/27/16
(b) A minimum of 4 inches of bedding must be placed before any pipe is laid.
(c) Minimum trench depth will be one foot of trench height above the top of pipe. This may
require building a pipe pad in fill sections before pipe placement.
607.3 HEADWALLS AND TOE WALLS
Headwalls and toe walls are constructed on pipe to maintain the roadway embankment or to
prevent undercutting and erosion of the pipe or flared end section. The fill face of headwalls
should be staked with 10 foot and 20 foot offset stakes and graded hub for elevation control.
Grade and line should only be provided for toe walls when precast units are to be employed.
The toe wall should have a depth of 30 inches minimum unless rock is encountered with a
minimum width of 12 inches. MSD substitutes grouted rock blanket in place of headwalls; 12
inches minimum above the pipe and sloped to match embankment slope.
607.4 PIPE COLLARS
Concrete pipe collars are used to extend existing pipe when a normal joint cannot be made to
connect two pipes of different diameter or to connect corrugated metal pipe to concrete pipe.
Pipe collars are designated as Type A and Type B.
Type A collars are composed of MSD Class A concrete, reinforced and formed to specific
dimensions for the size of pipe being joined as shown on the Detail Sheets. Type A collars are
designed for use in joining pipes of different diameters of where normal joints cannot be made.
Type B collars are composed of MSD Class A concrete; forming is not required, nor is
reinforcing. Type B collars are used to joint corrugated metal pipe to concrete pipe, to
waterproof and reinforce improper or separated pipe joints and to reinforce pipe connections to
stubs or into existing structures. Type B collars are to be minimum of 2 feet wide and a
minimum of 6 inches wider than the outside pipe diameter around the circumference of the
corrugated metal pipe atop the corrugations. (Note: Use of vibrators shall not be permitted;
concrete should be puddled and pushed under the pipe.)
607.5 INSPECTION OF PIPE LAYING
Inspection of laying procedures on all types of pipe will include:
(a) The bedding must be placed and formed so as to accept the pipe in the center of the pipe
trench with a minimum of 4 inches clearance on each side. The bedding must be formed
so as to uniformly support the pipe for its entire length, not just at the bell-spigot
connection.
128
Original Date: 1/3/94
Revised Date: 05/27/16
(b) Joint sealant or gaskets should be installed before the pipe is placed in the trench. Joint
sealant or gaskets should be placed on the spigot in sufficient quantity to provide a
complete seal around the circumference of the pipe.
Proper grade can be established by two methods – batter boards or laser.
608 BACKFILL
No separate payment will be made for trench backfill, around manholes, inlet manholes, catch
basins, inlets, junction chambers and other structures. No separate payment will be made for the
placing of backfill (either dirt or granular) uncompacted or consolidated by jetting or mechanical
means. Backfilling cost is included in the bid prices for pipe.
608.1 GRANULAR BACKFILL
Material used for granular backfill will be of a common type, generally designated as MSD 3
which is a ¾ inch minus crushed rock. Granular backfill is to be placed in not more than 6 inch
thick lifts to no less than 90 percent compaction. Granular backfill is required to subgrade only
when the trench will be within the pavement area, surfaced shoulders, paved approach areas and
sidewalk areas. Generally, all such areas will be specified on the sewer sheets in the plans.
When granular backfill is required, it will be placed so as to lock the pipe in place in the trench
and provide a compacted base for paved surfaces. All trenches are to be backfilled to subgrade.
When backfilling is done with earth, the earth will be placed and compacted as specified for
granular backfill. Prior to placing any earth backfill, the pipe must be bedded with granular
material as shown on the plans and compacted as required.
The main elements of inspection pertaining to backfilling are as follows:
(a) Proper backfilling material whether granular material or earth.
(b) Care in placing to ensure no damage to the pipe (from large pieces of rock or concrete
dropped directly on the pipe) or displacement of the pipe (by failure to properly and
evenly fill the space between the trench wall, pipe bedding and outside wall of pipe).
(c) Granular backfill to the specified height or spring line when using earth for backfill or
sanitary sewer construction.
(d) Proper lift thickness and compactive effort (including the addition of water if necessary).
(e) Complete filling of the pipe trench of subgrade.
129
Original Date: 1/3/94
Revised Date: 05/27/16
(f) Jetting, when allowed, shall be a process by which the trench backfill shall be uniformly
flooded and jetted with water and with care to avoid damage to the newly laid sewer.
After the backfill in the trench has substantially dried and completed its settlement, any
settlement below the finished grade shall be refilled with additional earth.
609 BORING
When permitted as an alternate method of construction by the plans and Specifications, or when
permitted in writing (upon written request by the contractor in substitution for the method of
construction shown on the plans), pipe sewers may be constructed in bored holes. The boring
machine to be used shall be in good mechanical condition and capable of drilling the bore hole
within the required limits of accuracy. A smooth liner of sufficient strength and a minimum of 2
feet in diameter shall be forced into the bored hole to give a tight fit against the earth sides of the
bore hole and still provide a uniform clearance of at least two inches around the pipe flange to
permit pressure grouting. The liner pipe shall be carefully inspected to ensure that the carrier
pipe can be properly placed. The pipe to be placed in the bore hole shall be Ductile Iron Pipe of
the required size and class. No plastic pipe shall be allowed. The mechanical or approved slipjoint connections between Ductile Iron Pipe lengths shall be made carefully in accordance with
the manufacturer’s instructions. After placing the assembled pipe in the bore hole, the ends shall
be blocked to secure the proper flow line elevations at each end and to ensure the placing of
grout at the bottom and sides of the pipe. If necessary or required, a skid or shoe shall be
provided for the pipe bell to permit flow of grout beneath the pipe and to prevent sagging and
pockets along the pipe flow line. The assembled and jointed pipe shall be placed in the bore hole
only by such method that will keep the joint in compression. Any method tending to upjoint the
pipe while being placed will not be permitted.
The spaces between the liner and the outside of the pipe shall be filled solidly with grout placed
under mechanical pressure. Before placing grout, the carrier pipe shall be carefully inspected for
uniformity of grade along its alignment, and any required corrections made. Particular attention
shall be given to ensuring that the pipe will be solidly supported by grout at its bottom and sides.
The method of injection under mechanical pressure shall be approved prior to being used. Grout
shall consist of an approved mix, and it shall be placed by inserting the grout pipe to its greater
distance to ensure filling all spaces and then gradually withdrawing the pipe as filling proceeds.
Manholes at the ends of a section of sewer, part or all of which is constructed in a bored hole,
shall not be constructed until the bored section is completed in order to allow corrections for
slight deviations in line and grade.
(a) Alignment control must be constantly monitored while boring and installation of the
casings are being performed. An inclinometer utilizing water in a stand pipe will be used
while the boring and casing placement is in progress to maintain the proper grade.
Tolerance in alignment is restricted to less than 1 percent of the total length of the bored
hole. Tolerance in elevation is restricted to no more than 0.1 foot overall.
130
Original Date: 1/3/94
Revised Date: 05/27/16
(b) All joints must be tight when placed in the casing and must not be dislodged while being
inserted to a final position.
(c) The sewer pipe must be securely supported and held in place while grout is being placed
between the sewer pipe and casing.
(d) Care must be taken to completely fill the void between the casing and sewer pipe. Grout
must be placed under pressure to ensure complete filling, and the hose used to fill the
void must be withdrawn in stages to completely fill the space.
610 GROUTING
When required in the plans to fill an existing channel or sewer line, grouting shall be done by the
contractor. Grout shall consist of a uniform mixture of Portland cement and sand. The use of
special cements or admixtures will be specified in the contract, if required. All grouting
equipment and appurtenance shall be in good mechanical working condition. Grout for filling
voids or spaces shall be applied through a pipe or hose under adequate pressure and removed as
grout fills the void.
611 FIELD MEASUREMENT
Field measurement will be made for completed pipe sewers, round or elliptical, for each size,
kind and class of pipe laid. Measurement of rigid pipe, complete in place, will be made to the
nearest linear foot along the geometrical centerline of the pipe. The length of pipe run to a
structure may be increased by not more than three feet as necessary to avoid cutting a pipe. For
sanitary sewers, combined sewers , storm sewers and other related pipe, measurement is to be
from inside of structure wall to inside of structure wall at the next structure.
Measurements shall be in accordance with the Specifications.
612 STRUCTURES
612.1 VERTICAL ALIGNMENT OF STRUCTURES
Structures shall not be out of plumb more than 1 foot in 30 feet in depth.
612.2 CONCRETE BASES
The base upon which the drainage facility is to be constructed will be MSD Class A concrete
(Note: Only the base of multiple inlet auxiliary units may be constructed of monolithic brick in
lieu of concrete). In either case, the concrete is required to produce a compressive strength of
131
Original Date: 1/3/94
Revised Date: 05/27/16
3500 pounds per square inch in 28 days. The Specifications require air entrained concrete placed,
finished and cured as concrete masonry and inspected as stated below:
(a) Reestablish the center of the structure after all excavation is completed. Make sure an
adequate volume of material has been removed to allow drainage facility construction
and backfilling (approximately 6 x 6 feet). Excavation for the base should extend to a
minimum depth of 8 inches below the flow line of all incoming and outfall pipes and
extend to at least the outside wall of the structure (Note: Additional width on structures is
recommended to facilitate form placement and placing brickwork).
(b) A keyway should be made at the center of the brickwork or formed wall completely
around the perimeter of the structure.
(c) Structure bases must be constructed to the size and shape shown on the typical Detail
Sheets included in the plans. When MSD structures are to be built, the shapes and
dimensions should be as specified in the MSD Standards unless superseded by Standard
Drawing or Special Provision.
612.3 BRICK
Brick for use in manholes and inlets shall be grade SM and will nominally be 8 inches in length,
3-3/4 inches in width and 2-1/4 inches in thickness with allowable variation of +1/4 inch in
width and thickness and +1/2 inch in length. The brick will be new, whole, of a uniform size and
substantially true shape with square corners. The brick will be of a compact texture, completely
fired, hard and free from injurious cracks and flaws. All brick not meeting these criteria will be
culled on site.
Brick masonry, plastering and mortar shall be protected against damage from freezing or lack of
moisture. Brick masonry shall not be constructed when the temperature is 40 degrees F or lower
without adequate approved means for protecting against freezing. Brick masonry shall have
sufficient moisture for proper curing and be protected from drying. Requirements for protection
of brick masonry and masonry materials are the same as required for concrete structures.
612.4 STEPS
Steps for use in drainage facilities shall be of an approved type composed of either aluminum
alloy, cast iron, or copolymer polypropylene plastic coated steel. The latter is approved for usage
in precast manhole units (MSD) or manholes built to MHTD standard. MSD approved steps for
concrete or brick structures are of two varieties; Type A steps are the most common and are
rectangular in shape (12 x 10-1/2 inches) and are intended to be used in structures on lines 54
inches in diameter or smaller. Type B steps are square in shape (14 x 14 inches), weighing 17
pounds and are intended for use in shafts or structures on lines 57 inches in diameter or larger.
132
Original Date: 1/3/94
Revised Date: 05/27/16
All steps in structures are to be 16 inch centers vertically. The first step in manholes will be ma
maximum of 31 inches maximum below the top grade of the manhole (or 24 inches below the
manhole brickwork). In inlets, the first step will be 24 inches below the top of the inlet stone.
Steps must protrude 4-1/2 inches (MSD) beyond the interior wall of the structure and must be
embedded a minimum of 6 inches in the sidewall. The Specifications require each step to carry a
concentrated load of 300 pounds. Steps should be so located as to be on an unobstructed wall
opposite of sills and outfall pipes. The bottom step shall be no more than 24 inches above the
invert shelf in manholes or lower than 3 inches above the overflow water line in trapped inlets.
612.5 TRANSITIONS
Transitions in brick area inlets are for both shape and size. The transition in area inlets is from
circular in the barrel of the structure (35 inches diameter) to rectangular at the sill opening (54 x
48 inches). The transition is to be made in a minimum vertical distance of 2 feet.
Transitions in grate inlets are for size and shape modification. In grate inlets with side intake
units, a transition is made from the brick barrel diameter of 35 inches to the precast grate inside
dimension of 29-1/4 inches (for 2 grate units) in 30 inches (vertically) from the top grade of the
grate to the inlet barrel. The same type of transitions as cited above prevail for 3 and 4 grate
inlets without side intake units constructed of brick. Transitions for size to accommodate 6 and 8
grate inlets are made by constructing an auxiliary base, 8 inches in thickness, with 4 inches of
fall from the face of wall opposite the main barrel into the main barrel. The auxiliary base is to
begin 18 inches below the structure top grade and end at 25 inches below the top grade parallel
to the flow line and also to begin at 18 inches below the structure top grade and end at 29 inches
below the top grade perpendicular to the flow line.
612.6 INVERTS
All structure bases must be sloped to drain or must be constructed with an invert. Manholes
(lines 36 inches and smaller) will be constructed with a base sloping from flow line of incoming
mainline to flow line of main outfall line. All additional incoming pipes will be built with an
invert to reach from its flow line to the main flow line. Invert shelves will be constructed to
channelize the flow in the structure and maintain a laminar flow condition in the main pipe line.
The invert will be formed to one-half the inside diameter of the outfall pipe and will be sloped to
drain. Manhole steps should be built over an invert shelf if possible. Terminal manholes are to
have bases constructed with 3 inches of fall from inside walls to the flow line of the outfall pipe,
unless house laterals are present which require an invert. Manholes on lines larger than 39 inches
in diameter will not require inverts for incoming lines as all lines enter above the springline or
require a junction chamber for connection.
All single curb inlets (trapped or untrapped), grate inlets and single area inlets are to be
constructed with 3 inches of fall from the wall to the center of the structure. Double inlets require
a total of 3 inches of fall from the inside wall of the auxiliary unit at the center of the structure to
the flow line of the outfall pipe with 1-1/2 inches of fall in the main barrel. As in single units, the
fall from the inside wall of the structure to the center of the unit will be 1-1/2 inches. The main
133
Original Date: 1/3/94
Revised Date: 05/27/16
barrel base in a multiple inlet should be constructed as a single inlet base with the base in the
auxiliary unit on a constant slope into the main barrel (6 inches in 54 inches). Inverts in multiple
units and structures cast-in-place may be poured after the structure is placed. MHTD grate inlets
also require an invert poured in place after the construction of a level base and sidewalls.
612.7 INSIDE DROP STRUCTURES
Inside drop structures require a 48 inch diameter manhole. The incoming pipe must be equipped
with a water stop on brick structures or a compression joint on precast structures where it enters
the manhole and must protrude 2 inches beyond the interior wall The drop pipe will be composed
of an 8 inch PVC pipe and 90 degree elbow which will discharge the effluent at the flow line of
the structure. The drop pipe will be attached to the structure sidewall by means of a ¾ inch
diameter stainless steel band on 60 inch centers (minimum of two required) anchored by a wall
bracket and two 3/8 x 3 inch stainless steel bolts.
612.8 REINFORCED STRUCTURES AND DROP STRUCTURES
Reinforced or drop structures are required by MSD when the following occur:
(a) In storm drainage facilities, incoming pipes of 21 inch diameter or larger which have
displaced flow line above the outfall lines require reinforced concrete base and sidewalls.
(b) In sanitary or combined facilities, any incoming flow line which has a displaced flow line
of more than 2 feet from the outfall line will require a drop structure.
Reinforced structures will be so designated on the sewer sheets, and a special detail will be
provided to show base and wall thickness, reinforcing steel size and configuration and height of
wall. Generally, only a portion of the entire structure will be reinforced. Drop structures are of
two types, designated as outside drop or inside drop. Outside drop manholes are being phased
out in lieu of inside drop structures due to cost and strength. Outside drop structures require a
larger concrete base to support the drop portion of the incoming line and integrally constructed
brick encasement of the drop pipe and an encasement of the over flow pipe, tee and incoming
pipe a minimum of two feet beyond the first joint beyond the tee.
612.9 INSPECTION OF STRUCTURES
The inspection of the brickwork on inlets and manholes should be in the following areas:
(a) Reestablish the center of the structure (main barrel on multiple or double units). Establish
a string line at roadway face of sill for alignment control. By taking given cut or fill into
account, place alignment control string line on grade or a parallel grade above or below
actual grade.
(b) By utilizing the string line, an accurate check can be made to determine proper elevation
control on structures being constructed. Alignment control must be maintained by
134
Original Date: 1/3/94
Revised Date: 05/27/16
properly placing the sill or measuring from offsets to the center of the structure.
Particular alignment control must be exercised on grate inlets with side intakes as the unit
must fit precisely in the curb line. The string line will establish the back face of the curb
line on grade to ensure the correct alignment and grade.
(c) The following items of information will be necessary to properly construct the brickwork
for inlets and manholes:
Inlet stones are 54 x 48 x 5 inches
Auxiliary unit stones are 54 x 32 x 5 inches
Inlet sills are 8 inches high, 6 inches wide and 32, 38 or 54 inches long.
Divider blocks (double and multiple inlets) are 22 x 13-1/4 x 9 inches
Pillars (area inlets) are 8 x 8 x 5-1/4 inches in height
Divider Block (area inlets) are 36-1/2 x 13-1/4 x 9 inches.
Standard inlet throat opening is 6 inches. (Opening for larger capacity requires
safety bar).
Roadway face of inlet stone is set 1 inch behind roadway face of inlet sill.
Standard manhole frame is 7-1/16 inches in height.
Standard mortar bed is ¾ inches in thickness.
Standard barrel diameter on manhole is 42 inches inside.
Standard barrel diameter on brick inlet is 35 inches inside.
Standard barrel diameter on concrete inlet is 42 inches inside.
Standard barrel diameter on grate inlet is 35 inches inside.
Standard inlet set back behind curb is 24 inches (See Standard Drawings).
(d) All pipe entering a structure must have a rowlock arch over the top of the pipe. This
requirement also applies to inlet pipes when connections to existing structures are made.
Prior to construction of the rowlock arch, one layer of smooth roofing paper (55 pounds)
or one coat of bituminous material should be placed on the pipe. When plastic (PVC)
pipe is allowed, a water stop will be set in place around the circumference of the pipe. A
double rowlock arch is required in structures containing pipes 39 inches or larger in
diameter.
(e) Transitions in shape and/or diameter are common in brick structures. In manhole
construction, a standard transition is required in each top section between the barrel
diameter of 42 inches and the frame opening diameter of 26-1/2 inches. The taper in
diameter is to be constructed not less than 36 inches vertically for brick manholes and not
less than 24 inches vertically for cast-in-place concrete manholes. Transitions in the
bottom section of manholes on lines larger than 24 inches in diameter are to provide for
changes in shape within the structure. The bottom sections of manholes on lines 27 thru
36 inches are to be square shaped and are to extend to a height of the diameter of the
largest pipe plus 12 inches with a transition to round (42 inches diameter) a minimum of
36 inches below the top of brickwork for the manhole (43-3/4 inches below top grade).
For cast-in-place concrete manholes on lines 27 thru 36 inches, the square shape is to
extend 8 inches above the inside diameter at the top of the largest pipe and then change to
135
Original Date: 1/3/94
Revised Date: 05/27/16
round (42 inch diameter with no transition). Transitions in manholes on lines 39 thru 54
inches in diameter of brick construction are both for shape and diameter. The bottom
section in brick manholes is to be rectangular from the base to the top of the double
rowlock over the largest diameter pipe and then transition to round in 24 inches. The size
of the manhole is to be transitioned from the size of the largest pipe inside diameter to 42
inches at the top of the transition from rectangular to round. Manholes on lines of this
diameter which are constructed of cast-in-place of concrete are to be built rectangular in
shape to a height of 8 inches above the inside diameter at the top of the largest pipe and
then built round (42 inch diameter) with no transition.
612.10 TUCKPOINTING AND PLASTERING EXISTING DRAINAGE STRUCTURES
All existing drainage structures located within the right-of-way and easement area shall be
inspected and treated as necessary. All existing structures are to be tuckpointed as needed and
plastered as necessary in order to waterproof them and prevent ground water infiltration. The
structures must be plastered with a ½ inch thick 1 to 3 mortar mix (by volume, Portland cement
to masonry sand) on the inside surface. The Resident Engineer will inspect all the structures with
the MSD inspector to make a determination of the repair work needed for each structure.
613 MANHOLE FRAMES AND COVERS
Manhole frames and covers are to be composed of cast iron. The manhole frame is to be
nominally 37-1/2 inches in diameter with an opening of 21-3/8 inches in diameter for entry into
the structure. This is the current standard for use on all manholes; however, in many of the older
areas of the County, small frames were used.
All castings shall be installed true to line and to the correct elevation upon a full bed of ¾ inch
thick mortar.
When replacement of the frame and cover is required or an overlay requires the use of a riser
ring, a size determination must be made well in advance to allow for fabrication of the nonstandard frame. The standard frame is 7-1/16 inches in height from the bottom of the base plate
to the top of the cover and weighs 240 pounds. A coating of an asphaltic emulsion is placed on
all frames and covers. The standard manhole cover (MSD Type A) is 23-5/8 inches in diameter,
weighs 196 pounds, is composed of cast iron and is coated with an asphaltic emulsion. These
covers are cast with two lifting slots and have raised lettering around the obverse circumference
stating “Metro St. Louis Sewer District Sewers.” When permitted, slotted manhole covers (MSD
Type B) may be used to intercept storm drainage. The slotted manhole cover is 23-5/8 inches in
diameter, weighs 152 pounds, is composed of cast iron and is coated and cast as the Type A
cover described above.
614 INLETS
614.1 INLET COVERS
136
Original Date: 1/3/94
Revised Date: 05/27/16
Inlet covers are two types. The standard (MSD) cast iron inlet cover weighs 85 pounds, is 24
inches in diameter, has one lifting notch and is cast with “Metro St. Louis Sewer District
Sewers” around the circumference on the obverse side. This cover is also coated with an
asphaltic emulsion. The alternate type of inlet cover is of precast reinforced 4-concrete and is 241/4 inches in diameter and 2 inches in thickness. Because of their size and thickness, these covers
require modified inlet stone.
614.2 GRATED INLETS
Grated inlets are to be used only in those locations where standard curb inlets cannot be used or
in paved traffic areas. The standard grate (MSD Type C) is rectangular in shape (30 x 15 inches),
weighs 256 pounds, is composed of cast iron, is coated with an asphaltic emulsion and is cast
with “Metro St. Louis Sewer District Sewers” on the cross bars of the grate. The grates are to be
situated parallel with the water flow, with the 30 inch side parallel with the curb. An MSD
alternate grate for use in these structures is composed of mile carbon steel designed to withstand
a H20 loading condition, weighs a minimum of 65 pounds and is coated with asphaltic emulsion.
County specifications require this alternate grate to be equipped with bicycle bars for safety.
The grate inlet frame (MSD) is to be built of 2 x 3 x 3/8 inch steel angle which is anchored with
a reinforced concrete base 8 inches wider than the clear opening of the grate. The following are
frame and concrete base dimensions for the various grate inlets:
2 grate
3 grate
4 grate
6 grate
8 grate
30-1/2 x 30-1/2 inch frame
30-1/2 x 45-1/2 inch frame
30-1/2 x 60-1/2 inch frame
60-1/2 x 45-1/2 inch frame
60-1/2 x 60-1/2 inch frame
43-1/4 x 43-1/4 inch base
58-1/2 x 43-1/4 inch base
73-3/4 x 43-1/4 inch base
58-1/2 x 74 inch base
74 x 74 inch base
Two, 3 and 4 grate inlet bases are 8-1/2 inches thick; 6 and 8 grate inlets bases are 13 inches
thick. In 6 and 8 grate inlets, a center support 8123 beam is included (56 inches in length for 6
grate inlets and 72 inches in length for 8 grate inlets). Grates are to be coated, 10 mil thick, with
an asphaltic emulsion (MSD) or galvanized (County).
614.3 SIDE INTAKE UNITS
Side intake units are designed for use in curb lines where standard curb inlet cannot be used or in
areas of limited easement. The MSD standard side intake unit is composed of cast iron, weighs
249 pounds, is 34 inches in length, 19 inches in height, 6 inches in width at the top and 12 inches
in width at the base. The unit is designed to sit directly in the curb line with the back of the hood
and the back of curb on line. The structure must be built in such a manner as to provide exact
elevation control for the side intake unit. This unit is coated with an asphaltic emulsion.
614.4 STREET INLETS
137
Original Date: 1/3/94
Revised Date: 05/27/16
All street inlets which are built of brick are to be equipped with a transition from the round (35
inch diameter) barrel to a shape resembling a “horseshoe” to accommodate the inlet sill. This
transition for shape is to be made in the top 14 inches of brickwork. On all brick inlets, minor
transitions in shape and size are to be made from the top of the rowlock arch on the outfall pipe
to the bottom of the sill.
614.5 INSPECTION OF INLETS
The major elements of inspection for all manhole and inlet construction are elevation control and
correct sill or unit alignment which have been discussed at length in Structures – 602.2. That
procedure can be used to inspect the drainage structure.
615 PRECAST AND CAST-IN-PLACE CONCRETE STRUCTURES
In most cases, precast concrete structures are not constructed on County projects. When by
Special Provision precast units are allowed, a special Detail Drawing will be included in the
Construction Plans. The major items of inspection on precast manholes are as follows;
(a) Tight, waterproof joints with rubber gaskets in proper alignment.
(b) Properly cast, graded and aligned openings for incoming pipes with proper compression
type gasket joints.
(c) Use of complete riser sections with final elevation adjustment made with brick. Elevation
adjustment is not to exceed 18 inches, including manhole frame.
(d) Properly placed and compacted backfill placed evenly in circumferential lifts.
Cast in place structures may, in most cases, be used as an alternate to brick structures (if
approved by MSD). In most cases, construction requirements vary for concrete structures from
brick structures in the following areas:
(a) Manhole top section transitions are 2 feet in length vs. 3 feet for brick.
(b) Concrete manholes and inlets do not require plastering on the outside surface for sanitary
or combined units.
(c) Shape transitions in manholes are not required. Rowlock arches are not required at pipe
openings.
(d) All units must be 42 inches inside diameter.
(e) Inlets require no shape transition to match sill.
(f) Area inlets require a 58 x 58 x 8 inch concrete pad at sill grade.
138
Original Date: 1/3/94
Revised Date: 05/27/16
615.1 INSPECTION OF CAST-IN-PLACE CONCRETE STRUCTURES
Inspection of cast-in-place concrete structures include the following elements:
(a) Elevation and alignment control will be the same as outlined for brick structures. Care
must be taken when setting forms to ensure plumb sidewalks are established on the base
to allow an accurate grade transfer before pouring the structure and after pouring to allow
a check on the grade.
(b) Spreaders must be placed at intervals to ensure that forms do not move and that wall
thickness is maintained at a constant 8 inch width.
(c) A check before and after pouring is necessary to ensure the proper barrel diameter and, in
manholes, proper manhole frame opening and transition distance.
(d) Care must be exercised when placing and vibrating concrete so as not to dislodge the wall
forms or “float” the forms from the pre-poured base.
(e) Steps must be inserted to the proper depth after the concrete is poured but before initial
set of the concrete begins.
(f) Form removal must be performed with a degree of care to prevent possible cracking of
the structure. Forms should not be removed for 24 hours, and any honeycombed areas
should be promptly patched. Excessive honeycomb is a cause for structure removal.
(g) Inverts will be constructed after forms are removed.
616 PRECAST CONCRETE BOX CULVERTS
Precast concrete box sections may be specified in the plans and are an approved alternate when
larger volumes of water exist.
617 STRUCTURES BUILT ON MoDOT RIGHT-OF-WAY
Structures built on MoDOT right-of-way will, in general, be constructed to MoDOT standards.
Most structures are cast-in-place or precast. As such, care must be taken to ensure compliance
with these requirements. Major differences in construction procedures and requirements include:
(a) Reinforced concrete sidewalks and bases of varying size and thickness.
(b) Grate shape, material, and safety requirements and means of attachment to the frame and
structure.
139
Original Date: 1/3/94
Revised Date: 05/27/16
(c) Step layout and spacing.
(d) Invert construction and plastering requirements.
618 EXISTING STRUCTURES
Existing drainage facilities are to be checked on each project and, where necessary, repaired to
maintain their usefulness. Tuckpointing of existing brickwork is included in the bid items on
most projects. Other repairs may be performed by Change Order or by MSD forces as directed
by your Regional Project Engineer Supervisor.
Connections to existing facilities will also require repairs to the structure as needed. The
contractor should exercise care in breaking into existing structures as damage done to the
structure as a result of his work will be his responsibility to repair. When grade adjustments to
existing facilities are required, the brickwork or concrete must be removed past the top section
transition and rebuilt.
Alignment corrections to existing structures will also require removal of brickwork or concrete
below the top section transition. Racking of the structure should not exceed 3 inches per foot
with the wall opposite the transition remaining vertical.
619 FIELD MEASUREMENTS
Structures are to be paid on “per each” basis without consideration of depth or size. Structures as
shown on the “B Sheet” and sewer sheets will give a top or sill grade and a flow line grade along
with the information as to the construction of the unit (reinforced, side openings for area inlets,
grate, etc.). In general, no additional compensation will be awarded to the contractor unless a
change in overall depth of structure occurs which exceeds one foot. The revision of sill openings,
size of structure or change of intended type of structure to be sued may be a basis for
compensation to the contractor. Payment is for a complete structure in place; no payment should
be made until covers, stones, backfill and frames are in place.
619.1 BASIS OF PAYMENT
The contractor shall not be entitled to receive additional compensation for anything furnished or
work performed except for extra work authorized by Change Order or for which provision has
been made in the Project Plans or Specifications which will state the method of measurement and
basis of payment for any items of construction not covered by this section of the Specifications.
Duplication of quantities, units or bid items will not be permitted even though the Project Plans
or Specifications may, through error or oversight, allow such duplication.
140
Original Date: 1/3/94
Revised Date: 05/27/16
Unless otherwise provided in the specifications, no additional payment will be made for curved
radius pipe which shall be measured and paid for in the same manner as described for straight
pipe. Any additional costs for curved or radius pipe shall be included in the bid price per linear
foot for pipe of the size, kind and class involved.
Payment for tees, wyes, bends, stubs, slant and other appurtenance required by the Project Plans
and Specifications will be at a bid price for each and in addition to the amount paid for the
completed pipe sewer containing such appurtenances (except where the cost of the appurtenance
is included in the lump sum bid price for a given item). The payment for any appurtenance shall
include furnishing and installing of an approved stopper, cap or cover.
Payment for pipe sewers will be made for completed pipe sewers, round or elliptical, for each
size, kind and class of pipe laid at the respective bid price per lineal foot. The length for which
payment will be made will be the measured horizontal distance for each along the centerline of
the pipe, inclusive of the distance between the inside faces of each connected structure, sewer
manhole, inlet manhole, inlet, junction chamber, transition section or other similar structures.
The payments made shall include all costs of labor, materials, tools and equipment and shall be
full payment for furnishing and installing pipe, joining materials, crushed limestone in
replacement of overdig and furnishing, placing and compacting the bedding and backfill.
620 GABION WALL INSULATION
Gabion wall insulation shall consist of furnishing and filling open wire mesh wire mattresses
with stone in accordance with the lines, grades and dimensions shown on the plans or as
established by the Resident Engineer during construction.
620.1 CONSTRUCTION STAKING
The staking requirements for gabion walls are as follows:
(a) From the plans, the toe elevation of the base of the wall will be determined and the
alignment at various locations staked at an offset usually dependent on the wall height.
(b) The wall batter, usually 1 foot vertical fall to 10 foot run toward back of wall (or as
shown on the plans) shall be written on back of the stake.
(c) At this time, a spot check should be made to assure that field conditions are reasonably
close to plan. If they are not, double check and inform your Regional Project Engineer
Supervisor.
620.2 MATERIALS
The following materials for gabion basket construction (see contract book for specific items)
should be inspected:
141
Original Date: 1/3/94
Revised Date: 05/27/16
(a) Gabion baskets shall be constructed of Hexagonal Triple Twist Mesh with heavily
galvanized steel wire that meets or exceeds that for Series 300 Heavy Duty Gabion
manufactured by Maccaferri Gabions.
(b) Filter fabric shall be a woven polypropylene material that meets strength requirements as
specified in the Special Provisions.
(c) Gabion Rock shall be 10 inch maximum size with 95 to 100 percent passing a 10 inch
screen and 4 inch minimum size.
(d) Crushed rock base with gradation and dimension shown on plans.
620.3 CONSTRUCTION REQUIREMENTS
The installation of gabion walls shall meet the following requirements:
(a) The site shall be cleared and excavated. The crushed rock base or leveling concrete
should be placed. If rock is encountered, a 2 to 4 inch thick MSD Class A concrete
leveling pad shall be placed.
(b) While this is being performed, the baskets shall be assembled with close inspection of:
(1) Fastener closure and splicing.
(2) Proper diaphragm assembly for gabion baskets exceeding 4 feet in length.
(3) Proper wire gauge.
(4) PVC coating of baskets on channel bottom and lowest 3 feet in height on the walls.
(5) Properly squared assembly of baskets with the top of all panels even. All vertical
edges of end and diaphragms shall be securely laced.
(c) Set assembled gabion baskets in their proper location and lace the perimeters of all
contact surfaces. Gabion rock shall be placed in the baskets with rock at all exposed faces
to be set by hand and to be placed in 1 foot lifts. Tension wires are then placed each foot
in height. The gabion is then slightly overfilled for settlement (2 inch maximum), the lid
folded down and secured with wire. It is important to keep tension in the wire while
baskets are being filled and to maintain design batter. Baskets are to be placed so that the
vertical joints are staggered.
(d) Gabions may be cut to form curves or to allow pipe connections. Cut or bent edges of the
mesh shall be fastened securely to another part of the gabion structure by lacing with
142
Original Date: 1/3/94
Revised Date: 05/27/16
wire. Concrete pipe collar or encasement may also be required depending on field
conditions.
(e) Filter fabric shall be placed between gabions and earth on all exposed sides extending
completely beneath the base row of gabions and up the sides of the bottom mat. Seams
between adjoining rolls of filter fabric shall be lapped 12 inches minimum and secured to
baskets every 18 inches to ensure tightness. Fabric shall be cut even to top of wall.
(f) Place and compact wall with approved backfill material with careful attention to backfill
method so that fabric or wall will not be damaged or moved out of place.
620.4 BASIS OF PAYMENT
Payment for gabions will be measured in their final position to the nearest cubic yard. The
payment for crushed rock or leveling concrete will be either as a Bid Item or as a Contingent
Item.
Unless otherwise provided in the contract, no additional payment will be made for filter fabric
material used for backfill or any reinforced geogrid that may be required in the crushed base.
No attempt will be made to separate or classify excavation quantities for gabion construction. All
excavation will be considered unclassified.
621 SINKHOLE AREAS
A sinkhole report will be required where improvements are proposed in any area identified as a
sinkhole area . This report is to be prepared by a Professional Engineer, registered in the State of
Missouri, with demonstrated expertise in geotechnical engineering and shall bear his or her seal.
The sinkhole report shall verify the adaptability of grading and improvements with the soil and
geologic conditions available in the sinkhole areas. Sinkholes shall be inspected to determine
their functional capabilities with regard to handling drainage.
The report shall contain provisions for the sinkholes to be utilized as follows:
(a) All sinkhole crevices shall be located on the plan. Functioning sinkholes may be utilized
as a point of drainage discharge by a standard drainage structure with a properly sized
outfall pipe provided to an adequate natural discharge point, such as a ditch, creek, river,
etc.
(b) Non-functioning sinkholes and sinkholes under a proposed building may be capped.
(c) Sinkholes that are left in their natural state will require a properly sized outfall pipe to an
adequate natural discharge point.
143
Original Date: 1/3/94
Revised Date: 05/27/16
(d) All sinkholes must be inspected by the Resident Engineer and the MSD inspector prior to
treatment. Special siltation measures shall be installed during the excavation and grading
operations of sinkholes to prevent siltation of the sinkhole crevice.
(e) Excavation – Prior to a filling operation in the vicinity of a sinkhole, the earth in the
bottom of the depression will be excavated to expose the fissure(s) in the bedrock. The
length of fissure exposed will vary, but must include all unfilled voids or fissure widths
greater than ½ inch maximum dimensions which are not filled with plastic clay.
(f) Closing Fissures – The fissure or void will be exposed until bedrock is encountered in its
natural attitude, form or state. The rock will be cleaned of loose material, the fissures will
be hand-packed with quarry run rock of sufficient size to prevent entry of this rock into
the fissures and all the voids between the hand-packed quarry run rock filled with smaller
rock so as to prevent the overlying material’s entry into the fissures. For a large opening a
structural (concrete) dome will be constructed with vents to permit the flow of
groundwater.
(g) Placing Filter Material – Approved material of various gradation will be placed on top of
the hand-packed rock with careful attention paid to the minimum thicknesses. The filter
material must permit either upward or downward flow without loss of the overlying
material.
The fill placed over the granular filter may include granular material consisting of clean
(no screenings) crushed limestone from a 1 to 10 inch maximum size or an earth fill
compacted to a minimum density of 90 percent as determined by ASTM D1557-64T .
(h) Supervision – Periodic supervision of the cleaning of the rock fissures must be furnished
by the Soils Engineer who prepared the Soil Report. Closure of the rock fissures will not
be permitted until the cleaning has been inspected and approved by that soils Engineer,
the MSD inspector or the Resident Engineer.
Continuous visional supervision shall be required during the placement and compacting
of earth fill over the filter. Earth fill densities will be determined during the placement
and compaction of the fill.
144
Original Date: 1/3/94
Revised Date: 05/27/16
SECTION 700
STRUCTURES
701
GENERAL
Bridge and culvert inspection will require the most extensive effort of any inspection.
Inexperienced personnel should not be placed in an inspection position on a structure.
Tolerance for error will be, at most, the nearest ⅛inch, and in some applications, no
margin for error is allowed. A thorough knowledge of the plans, specifications and
construction procedures is essential.
702
SURVEY LAYOUT PRINCIPLES
702.1 BRIDGES
The Resident Engineer should check the accuracy of the initial layout for location, correct
stationing, alignment, offset distances, span lengths and bench mark elevation. All stakes should
be clearly and concisely marked, and the location of all pertinent stakes should be known by the
contractor’s personnel and all inspection personnel. Inspection of the staking during the life of
the bridge construction should include:
(a) Establishment of one bench mark so located as to be visible form the entire structure,
if possible, tied to the elevation datum used to design the structure. This bench mark
should be used to establish elevation on all elements of the structure. All elevations
on the structure should be established by direct reading from this bench mark.
(b) Centerline should be established in such a manner that it may quickly be replaced if
destroyed. Most important are points on tangent which are established at intervals
from adjacent to the structure to several hundred feet away. These points will
determine the accuracy of the bridge alignment and should be established at each
abutment and should be checked for tampering or movement at frequent intervals. A
minimum of 3 points on tangent should be set from each abutment. When offset or
working lines are used in lieu of or in addition to centerline, they should be tied to
centerline and set with visible points on tangent in a similar manner to permit
accurate reestablishment on the line. If working lines or offset lines are used to
establish alignment, they should be used exclusively during the construction process
and not mixed with centerline measurements.
(c) Fill face and centerline of bent stakes should be set at the intersection with centerline
and with working lines. . Offset distances should be coordinated with the
Contractor. One common mistake in these staking procedures is to confuse the line
staked with the nomenclature on the stake. Coordinate with the Contractor on the
145
Original Date: 1/3/94
Revised Date: 05/27/16
preferred control line to be staked (i.e. centerline line of abutment, center of bearing
or fill face of abutment.) A close check by station should disclose the accuracy of the
staking. At the intermediate piers, a common mistake is to confuse the centerline of
bent with centerline of bearing. This can be checked again by stationing or by
checking span lengths. (In some cases, centerline of bearing and centerline of bent
may be the same line; a check of the plans will indicate proper location and
stationing). Another common error is improperly turning the skew angle of each
pier. Under normal circumstances, the abutments and intermediate bents will be on
the same skew which will produce parallel lines. By measuring from these lines, a
constant distance will appear along the length of the bent which will prove their
parallelism. Another check is to compute the diagonal distance from end of one bent
to the opposite end of the parallel bent. Since the bent length, span length and angle
are known, the diagonal distance can be readily computed and measured. The
measured distance must be equal for parallelism to exist. For bent which are not on
the same skew or bents which will produce a horizontal curve in the structure,
compute distances for span lengths should be provided in the bridge layout sheets.
These distances should be closely checked at various locations for staking accuracy.
(d) Constant checks on alignment and elevation should reduce the chance for error
greatly. The substructure units should be constructed in sequence assuming that the
location of the first unit is correct and all other units are built in direct relation to it.
Elevation control will be crucial at the beam seat elevation. Minor elevation
differences can be corrected to this point.
These principal lines will provide all the alignment information necessary to construct the
bridge. Additional staking may be required for the contractor to help facilitate their own
or subcontractor operations, and this subsequent staking must be checked for accuracy as
the work progresses. In all cases, the first substructure unit completed will be
considered as monumental, and all span dimensions and future layout will be based on
measurements from the working lines thus established.
Elevation staking will be primarily a graded hub at a given offset with a cut or full to the
desired elevation. As elevation of substructure units is a major source of error, all grades
should be checked by sighting after the form work is in place. Care should be taken to
double check all transferred grades. Precision elevations will be required for bridge beam
seats where a bearing assembly is to be installed.
In rare instances, triangulation will be necessary to establish working points and lines for
substructure units. A base line for triangulation having a minimum length of twice the
total span length of the structure on each side of the centerline will be required.
The typical construction staking for a bridge is shown in Illustration 702.1:
{Insert illustration}
146
Original Date: 1/3/94
Revised Date: 05/27/16
ILLUSTRATION 702.1 – TYPICAL BRIDGE STAKING PLAN
702.2 BOX CULVERTS
Box culverts will be staked in a similar manner with centerline of roadway, centerline of
structure and fill face of headwalls being shown on offset stakes to establish working
lines. Offset distances should be coordinated with the contractor to allow enough
distance for removals and new construction. After the initial removals additional staking
may be required in the creek channel for construction.
Additional stakes may be requested by the contractor for the end of the floor of the box
culvert or to aid in the alignment of long structures.
Elevation staking will be primarily a graded hub at a given offset with a cut or fill to the
desired elevation. Because of the unstable material occasionally encountered in creek
bottoms, care should be taken to offset these grade stakes distant enough to assure they
will remain undisturbed and accurate. Stakes similar to paving staking should be used for
the floor of the box culvert. Care should be taken to establish a true grade and slope for
the floor of the box culvert as the walls and top deck are built in a direct relationship to
the floor elevations.
{INSERT ILLUSTRATION}
ILLUSTRATION 702.2 – TYPICAL BOX CULVERT STAKING PLAN
The headwall and/or wingwalls on the box culvert should be checked for proper elevation
and slope in relation to the roadway and surrounding objects. The detail sections of the
box culvert plans should provide a finish grade for the headwall and/or wingwalls which
should maintain a constant height above or below the sidewalk or shoulder of the
roadway. This grade should be checked to confirm a constant vertical height separation
and parallel slopes on headwall and sidewalk. Headwalls which will be in the slope or
are below the line of sight of the motorist will usually be built level.
Where the top deck of the box culvert is a portion of the traveling surface of the roadway,
care should be taken to check the grades of the culvert top deck as opposed to the
proposed roadway grades.
Checks on the survey layout of a box culvert are almost identical to that of a bridge.
Elevation will be controlled by a single bench mark accessible from the total structure.
147
Original Date: 1/3/94
Revised Date: 05/27/16
Alignment will be controlled by centerline and points on tangent thereon. The fill face of
the headwall on each side will be staked and should be checked for parallelism. Because
of unstable soil conditions to box culvert sites, frequent checks on all survey stakes
should be made to determine the accuracy of their placement.
702.3 RETAINING WALLS
The staking requirements for the retaining wall are divided between the footing and the
wall stem. The footing alignment should be staked at fill face of the wall stem or
centerline of the footing. Alignment stakes should be set on stated offset and at each end
of the footing as shown in Illustration 702.3.
Elevation control should be but or fill tacked hubs set to finish top of footing grade. The
wall stem should be staked for alignment by offset stake to top of wall at fill face. Care
should be taken to provide an offset distance sufficient to allow for needed excavation.
By staking fill face at top of wall, vertical wall places or battered walls planes may be
provided for. Elevation control should be by cut or hub at a given offset to top of wall or
by direct measurement from the top of footing to top of wall.
{Insert illustration}
ILLUSTRATION 702.3 – TYPICAL RETAINING WALLS STAKING PLAN
702.4 HAUNCHING
After any beam is set in place on a bearing assembly, it will deflect due to its own weight.
To counteract this deflection and the dead load deflection imposed by the weight of the
deck, a specified camber is incorporated into the beam at the time of manufacture.
Because the camber is based on theoretical computation, an actual field determination of
deflection is required. In order to determine the elevation of the deflection points, an
actual elevation must be taken at each point after the beam is set in position. The
Resident Engineer should enlist the assistance of the contractor and the Survey Party to
locate the deflection points and elevation at these points on the beams. Haunching
determination should be provided to the contractor in inches for each deflection point per
beam. Normally, grades are given at both centerlines of bearing, quarter points and at
mid-span of each girder.
703
SHEET PILING
Sheet piling in many cases, will be required to stabilize the soil adjoining an open footing
excavation to brace or support an existing roadway or to seal infiltration water from a
148
Original Date: 1/3/94
Revised Date: 05/27/16
footing site. Sheet piling will be laid out and driven to elevations shown on the plans or
the approved shop drawings, if required. Sheet piling should be driven vertically and
tightly connected between each section. Sheet piling will be removed upon completion
of the footing construction unless it is approved or shown on the plans to be left in place.
When sheet piling is removed, it may be necessary to excavate and recompact the
adjacent soil on each side of the sheet piling to avoid a division line in the roadway
embankment. Care should be taken when removing sheet piling to avoid undue vibration
caused by the extractor and subsurface voids by working the sheets back and forth to ease
removal.
Pneumatic caissons are used when work is to be performed at extreme depth for
foundations at major river crossings. Because this type of construction is infrequently
performed, inspection procedures will be included in the Job Special Provisions.
704
FOUNDATIONS
Foundations for substructural units on bridges and retaining walls will be of three types
of combinations of these types. The types of supporting units used in foundations are
poured in place, pedestal piling and bearing piling. The method of construction will be
different for each type of foundations and will require a variety of inspection techniques.
704.1 POURED IN PLACE FOUNDATION
Foundations which are cast in place on a stable soil or rock bearing material constitute a
type of foundation system in use for structural applications. Normally, this foundation
system is only employed when a stable soil or rock mass is available; for this reason it is
important to establish the quality of the bearing material early in the construction process.
In soil, this can be accomplished by obtaining a copy of the geotechnical report provided
to the Bridge Engineer by the Consultant Engineer which will provide strata elevations of
bearing soil, soil characteristics and boring reports for the foundation. In rock bearing
footings, the quality of the bearing material can be determined by drilling pilot holes for
subsurface investigation as explained in the section on pedestal pile. The most common
problem to be encountered in the rock bearing footing will be crevices or solution
channels in the rock at or below grade. When this problem occurs, fill concrete is often
used to fill the void and provide adequate support. Payment for fill concrete as a
Contingent Item is provided in the Standard Specifications.
The excavation required for soil bearing footings will be more exacting than for other
applications. The elevation will be rigidly controlled so as to produce an undisturbed
surface on which the foundation may rest.
When excavation is by rock blasting, techniques may be utilized to remove the
overburden to a point 18 inches above the top of footing only. All other excavation
should be by hand methods or by mechanical methods. Removal using explosives below
this 18 inch limit must be approved by the Bridge Engineer. Normally, all footings in
149
Original Date: 1/3/94
Revised Date: 05/27/16
rock will be keyed in a minimum of 6 inches in sound limestone and a minimum of 18
inches in shale of sandstone. These keyed-in sections should be so produced as to have
straight vertical sides, level bottoms and as few fractures in the rock as possible. Prior to
commencement make sure all necessary approvals and permits for the rock blasting have
been obtained per the Standard Specifications and any applicable Job Special Provisions.
The final bearing surface produced in either material should be solidly intact, on grade,
free of loose or scaly material and without obvious physical defects which would lower
the bearing capacity of the soil or rock. Should these characteristics not be present,
contact your Regional Project Engineer Supervisor or the Bridge Engineer immediately.
704.2 PEDESTAL PILING
Pedestal piling will be placed at the locations shown on the plans. This location will
always be established from centerline, or a working line, and all pedestal piling in any
one bent will be established on the same line from a common point of intersection. The
elevation of the top and bottom of the pedestal pile will be established in the plans. The
lower elevation of the pedestal pile will be set by the Resident Engineer after inspection
of the quality of the material at the proposed elevation. If the pedestal is to be set into a
rock strata for bearing, the final elevation will be dependent on the quality of the rock
underlying the plan elevation. To determine the rock quality, pilot holes will be drilled
and seam thickness and number will be determined and checked against the criteria
established by the Bridge Engineer. In addition, cavities and crevices appearing in the
side wall of the pedestal pile will be cleaned and measured for filling during this
inspection procedure. When pedestal piling are used in stable soils and soft rock,
inspection by the Resident Engineer of the bearing material, in light of the criteria
established by the Bridge Engineer, will again determine the lower elevation for the
piling. Pedestal piling in softer rock and stable soils are often belled at the bottom to
expand the bearing area. This procedure will result in the need for hand cleaning in the
widened area. Work requirements, restrictions, etc. including test holes should be shown
on the plans or specified in a JSP.
Equipment used in the construction of pedestal pile is usually confined to a truck
mounted rotary drill and appurtenances. In most cases, the drill is mounted to an
operating platform and can be tilted and moved horizontally and laterally for alignment
purposes. When drilling in stable soil, an auger will be used to remove the material to be
excavated for the pile. The auger must be the same diameter as that specified for the
piling. When unstable material is to be removed or drilling is to extend into bed rock, a
casing may be required to prevent caving of the soil sidewalls of the pedestal pile. When
this procedure is applied, and oversized hole must be drilled to accommodate the casing.
No additional payment will be made for additional excavation, use of casing, or
additional concrete required to fill the increased volume. The added equipment necessary
to complete the drilling of a pedestal pile will consist of a core barrel which is equipped
with carbide tipped teeth used to drill into rock, a clean-out barrel which is designed to
150
Original Date: 1/3/94
Revised Date: 05/27/16
pick up loose rock and dirt for removal from the shaft and a “Kelly” bar used to break the
rock into manageable sized pieces.
When the pedestal pile has been inspected and approved for further construction, the
reinforcing steel may be placed. The cage must be positively supported to obtain the
required elevation for splice length into the column and must be properly aligned to
implement extension of the reinforcing steel into the column and pier cap. It is most
important to properly align the vertical bars to properly intersect the horizontal bars in the
bottom of the pier cap. Because of the large bar diameters used in these two locations,
proper alignment will be necessary to ensure clearance distances and bar placing at the
required center distances. Positive supports and stand offs for the reinforcing steel will
consist of bar legs attached to the cage, approved chairs or tipped stand offs and the
supporting of the cage by a cable line from a crane.
Inspection of the concrete pour will be hampered by a number of factors and conditions.
Because the pour is confined to a small area with a number of simultaneous operations,
working room will be cramped. In addition, the reinforcing steel will project from the
pedestal shaft. Also, in most cases, the main cable on the drill derrick will be attached to
the casing to be retracted and the whip line will be attached to a hopper-tremie system for
conveying the concrete during the pour.
Inspection of the pour should include:
a. The shaft should be dewatered by submersible pump until ready to pour when the
pump will be withdrawn. If the shaft cannot be dewatered, seal concrete may be
placed in the water to a height of at least 2 feet above the bottom of the casting or
higher, if necessary, to overcome the hydrostatic pressure. The pour will then be
suspended until the concrete has cured sufficiently to allow the next pour to be
placed in the dry shaft.
b. Concrete shall be vibrated as placed. The top elevation of the pedestal should be
monitored and the pour stopped on grade.
c. The reinforcing steel should be periodically checked for plumb. Correction for
plumb should be made as the pour progresses. It is virtually impossible to plumb
the reinforcing steel cage when the pedestal shaft is poured to grade. Also check
alignment.
d. Upon completion of the pour, it will be useful to place a nail on line and at center
of pile as a future survey reference point before the concrete reaches its initial
set.
e. Work on site closer than 20 feet which involves driving pile or drilling additional
pedestals will be halted until the concrete has obtained a compressive strength of
1,500 pounds per square inch.
151
Original Date: 1/3/94
Revised Date: 05/27/16
Final elevations should be recorded and shown on the as-built drawings.
705
BEARING PILE
Bearing piles are of two distinct types –concrete and steel. Bearing pile foundations are
based on a certain minimum penetration of the piling into the subsurface material and the
attainment of a specified minimum bearing value per pile. In general, a minimum pile tip
elevation will be shown in the Construction Plan, and all piling will be driven at a
minimum to this elevation. This minimum tip elevation should always be obtained and,
when required, exceeded to obtain the required bearing value per pile. In every case, the
stated bearing value must be met before pile is considered completed. In the event of
not being able to obtain the minimum piling length requirement, the Bridge Engineer and
your Regional Project Supervisor should be contacted immediately.
Under normal field conditions, the required bearing value per pile is evaluated as a
function of penetration. Actual field bearing values may be obtained by static load
testing (when required) or by utilizing the Dynamic Bearing Formula as enumerated in
the Specifications. Values in terms of penetration per 10 to 20 blows may be used to
measure field bearing. The contractor can supply all required information about the
piling and driving hammer to make this determination by formula possibility. By using
the penetration per blow method of determining bearing, a quantity defined as practical
refusal may be obtained. Contact the Bridge Section to confirm the current Dynamic
Bearing Formula to be used and have them double check your calculations in determining
the minimum penetration per specified # of blows. Concrete pile will necessitate the
use of a bearing value not to exceed 10 tons in excess of the design bearing value. In all
cases, the design bearing value must be obtained for all pile types except structural steel
which will be driven to practical refusal.
705.1 PILING MATERIAL
Precast concrete pile shall be manufactured to an approved section for shape. Driven
metal shell for cast-in-place concrete pile shall be checked for distortion before any
concrete is cast in the shell. The shell shall also be clean and uncontaminated by dirt or
debris when the concrete casting takes place. Any ground water collecting in the shell
prior to casting shall be removed.
All piling should be moved carefully and placed on supports at the work site to properly
support the piling’s length. Damage incurred during handling will be the sole
responsibility of the contractor and may be a cause for rejection of the piling. Each pile
should be inspected before placing in the leads for driving, and rejected piling should be
marked and discarded.
705.2 PILING DRIVING EQUIPMENT
152
Original Date: 1/3/94
Revised Date: 05/27/16
The power hammers used to drive piling are of two major types: diesel and pneumatic.
The basic principles employed in the driving of the pile is of two classes. The first is
defined as a single acting hammer in which gravity produces the power stroke and the
external power source is used to raise the hammer between strokes. The second is
defined as a double acting hammer in which the power stroke and return stroke are both
powered by an external power source. When diesel powered hammers are to be used, the
type of ram or striking part of the hammer will determine the energy rating of the
hammer. For open rams, 75 percent of the manufacturer’s stated energy rating will be
allowed. For fully enclosed rams, the manufacturer’s evaluation charts and a bounce
pressure gauge will be required to establish the equivalent manufacturer’s rated energy.
The driving mandrel is composed of a cylindrical shoe which sits atop the pile (of
whatever type) and a cylindrical holder into which the ram strikes. The holder contains
jute mats or steel plates, or a combination of both, to center and transmit the power of
each blow without bending, brooming or shattering the pile. Also integral in most power
hammers is a trip lever which is adjustable to control the length of fall of the hammer. A
kinetic hammer device is often used to remove piling after driving has been previously
completed. The most common application of the kinetic hammer is in the removal of
sheet pile.
The power driven hammer is mounted within an assembly referred as the leads. The
leads are composed of rail guides in which the hammer is free to move vertically and a
framework composed of horizontal and vertical steel member and braces which constitute
the positioning and driving platform for the piling operation. The lead assembly comes
in variable lengths and must fully enclose the hammer and piling to work correctly and in
a safe manner. The leads used for driving battered piling must be rigid and should be so
constructed as to allow inclination as required to be the desired driving angle.
Additional equipment used in connection with the lead assembly are water jets and
followers. Water jets are used to aid in the driving of piling by loosening and eroding the
soil adjacent to the piling as it is driven. The volume of pressure of the water must be
regulated at the nozzles to achieve the desired results. When water jets are used, they
should be discontinued above the tip elevation stated in the plans with a minimum of 2
feet of pile driven into the existing soil, if possible. Follows are in reality a pile extension
which will allow the piling to be driven beyond the existing ground line at the work site
with a splice being made at a later date. The most common application is with precast
concrete pile.
In addition to the above described equipment, the most important component to the pile
driving operation is the crane. Normally, the crane will be track mounted with from 50 to
100 feet of main boom in position during the driving sequence. The crane must be of
sufficient power and rated tonnage to lift and hold the lead-hammer assembly during the
driving sequence. Normally, a 3 cable block rigging will be used during the driving
operation with the main cable attached to the leads and the auxiliary cable used as a whip
line to the piling. Additional equipment necessary to properly place piling is an electric
153
Original Date: 1/3/94
Revised Date: 05/27/16
welder and an acetylene torch. This equipment will be necessary to attain proper
elevation on the driven pile for inclusion in the footing.
705.3 PILE DRIVING PROCEDURE REVIEW
Before any piling can be driven, the excavation for the footing must be substantially
completed. Where piling is to be driven through more than 5 feet of compacted fill
embankment, it will be necessary to prebore holes through the fill to the existing ground
line to allow placing of the piling. The hole is to be backfilled and compacted with sand
or other suitable material. The space around any type pile after it is driven shall be
completely filled with a non-excavatable ready-mix flowable fill. No direct payment will
be made for the prebored holes thru compacted embankment or the non-excavatable
ready-mix flowable fill.
When test piles are to be placed in a foundation, the above requirements will be waived.
Test piles may be driven at a point where the excavation is within 2 feet of the proposed
grade. When test piles are to be left in place as permanent piling, it will be necessary to
designate the proper position of the pile within the footing. Test piles are the of the same
material and size as the permanent pile and are to be driven full length, or to refusal, or to
bearing value 50 percent greater than the required design bearing. In all cases, minimum
tip elevation must be attained. When pile length are specified in the plan, the test pile
provided will be at least 10 feet in length longer than specified length for permanent pile.
Test pile will be paid to the nearest lineal foot for the length authorized and driven.
When left as permanent pile, test pile will be paid as such.
Before any permanent piling is driven, it will be necessary for the Resident Engineer to
lay out the footing perimeter and the pile locations. The location of each pile should be
shown by a hub placed at the center of pile. Battered piling should be so designated.
Also a temporary bench mark should be set for piling cutoff elevation if the primary
bridge bench mark is unobservable. Before the actual pile driving begins, the Resident
Engineer should compute the penetration per 10 blows necessary to obtain the required
bearing or practical refusal, whichever applies. The contractor must provide two copies
of material certification for the piling provided. The certification should contain heat
treatment numbers and the testing procedure designation (ASTM or ASE). Further,
piling should be accurately measured and marked near the top with keil to show its heat
number and original length prior to placing. All information pertaining to pile driving
and the actual pile driving information should be recorded in a “Pile Driving Data”
project file. This form is self-explanatory and should be completed as each pile is
placed. Numbering of the piling in each footing should follow some logical sequence
and be correlated to both measured pile length and specific heat treatment number. The
numbering sequence should also be recorded in your pile driving data file and shown on
the project as-built drawings..
When the actual pile driving commences, the major item on the Resident Engineer’s
mind should be the safety of the inspection personnel. Because of the nature of the work
154
Original Date: 1/3/94
Revised Date: 05/27/16
and the risk of injury, all possible precautions should be taken while working near this
operation. Inspection personnel should wear hard hats, safety glasses and ear protection
whenever near the site. If you or your inspection personnel feel that the field conditions
are unsafe talk with the Contractor about corrective actions. If needed contact your
Regional Project Supervisor and/or St. Louis County’s Safety Division for assistance.
DO NOT put your inspection personnel into a condition you feel is unsafe. The
inspection personnel should learn hand signals for crane operations and should watch the
pile driving foreman to determine what events are about to take place. In general, only
one man will be required to observe the piling while being driven in the proximity of the
leads. All other personnel should stay well back out of the way and away from the crane
or piling stacked for use. Always watch what is going on, stay alert and out of the way as
much as possible. It is also a good idea to wear old clothes or rain gear – pile driving is
a dirty, greasy business and you will ruin your clothing.
In general, the actual pile driving sequence will begin by spotting the crane and leveling
the treads. When the crane is placed on a bank above the footing site, periodic checks
should be made for cracking in the vertical bank caused by vibration and for caving of
large portions of the back into the footing area. Once the crane is set and the air lines are
run to the crane and up the boom, the lead assembly will be raised and the hammer
mounted in the leads. When pneumatic powered hammers are used, the main shutoff
valve will always be just outside of the operator’s compartment on the right side of the
machine. On diesel powered hammers, the shutoff valve will be on the hammer itself and
will be operated by a control lever with a pull rope. Normally, the leads will be
suspended over the footing site close to the ground with a guide rope attached to the base
of the lead assembly to prevent turning of the leads. The whip line will be attached to the
pile at the stack by means of clevis and the pile raised into the leads and placed in driving
position. The inspector at the driving site should be careful to keep the leads between
himself and the pile stack while the pile is placed in the leads for driving. The whip line
and clevis should be accessible from the front of the leads for removal during driving,
and the whip line should be free of the leads.
The next step in the driving sequence is most important from the inspection standpoint.
The pile will be centered on the hub for driving by approximating the final location of the
leads and setting the pile in place. Following this, the leads will be set in place, centered
as much as possible on the pile and allowed to rest on the subgrade to provide a stable
driving support. The leads and pile will then be plumbed as the pile is set under the
driving mandrel. The pile can be moved so as to be “squared up” in the footing by a
wrench maintained for this purpose in the hand tools of the crew. For vertical driven pile,
the pile should again be checked for plumb and the weight of the hammer allowed to
make the initial penetration of the pile into the soil. For the battered pile, the leads
should be inclined to the proper slope and checked and the hammer weight allowed to
come to rest on the pile. In order to facilitate the checking of battered pile for inclination,
the contractor should be required to furnish a slope gauge which, when combined with a
level, will indicate plumb at the proposed inclination. Once the initial weight of the
hammer has been applied to the pile and the initial penetration has been obtained, the
155
Original Date: 1/3/94
Revised Date: 05/27/16
inspector may request that the pile and leads be re-plumbed before driving operations
begin. Should an error be discovered, the piling can usually be brought into line by
moving the leads. If moving the leads is unsuccessful, the piling will have to be
withdrawn and reset.
Before the actual driving begins, the inspector should take several safety precautions:
a. Make sure the alignment bars are in place on the lower part of the leads on each
side of the piling. These alignment bars should be left in place during the entire
operation.
b. Make sure the whip line is slack and not entangled in the leads.
c. Observe the wind direction and try to get upwind of the driving operation. Dirt,
oil, grease, etc. will be thrown by the hammer strike. Watch for falling debris.
d. Never get in front of the piling when driving has just commenced and stay out
from in front of the piling until necessary to check penetration for bearing.
Broken piling will fly out from the front openings of the leads when being driven.
As the pile driving proceeds, the inspector should observe the rate of penetration and the
plumbness of the pile. In certain soils, and especially in creek bottoms with scattered
boulders, the piling may slide or turn in the leads while being driven; should this occur,
the driving should be stopped and alignment and plumbness correction made or the pile
extracted and re-driven. Where thin layers of shale or limestone are to be encountered
and penetrated, apparent practical refusal may be indicated but not really obtained. In
such areas, a knowledge of rock strata and expected elevation of ledges to be encountered
can be obtained from the boring logs usually contained in the Construction Plans. It is a
good idea to be aware of the anticipated pile length for each location. When measuring
the piling in the stack prior to placement mark the piling at 5 foot intervals (from the
bottom) starting about the mid-point of the pile to aid in depth determination. Piling shall
be driven to a tolerance equal to not more than ¼ inch per foot from vertical or the
proposed batter alignment. The head of the pile in final position shall not vary from the
plan location by more than 2 inches, except in footing entirely below the finish ground
line where a maximum of 6 inches variation will be permitted. If any of these conditions
occur contact the Bridge Section to discuss corrective actions, if any, to be taken.
When the driving of the piling has reached the expected depth indicated by the minimum
tip, elevation checks should be made for practical refusal. Normally, one of the pile
drivers will assist you in the determination of this quantitative check. The normal
procedure is to place a four foot level on a solid support at ground level (not your toe)
and mark at the end of the level as it rests against the pile. By counting ten blows and
remarking the pile, it is possible to measure the actual penetration and compare the
results against expected values for practical refusal. In some cases, the pile driver will
mark the side of the leads and the pile to determine penetration; this practice should not
156
Original Date: 1/3/94
Revised Date: 05/27/16
be used due to the inaccuracy caused by the oscillation of the leads caused by the hammer
strikes. The tendency is to begin checking for practical refusal too early in the driving
process. By observing the frequency of the hammer strike, the inspector can tell when
little or no penetration is occurring. Another problem is to stop driving on a pile as soon
as the penetration slows. Because of the varying uncharted geological conditions, the
pile may appear to be at practical refusal when a few more blows may result in increased
penetration and insufficient bearing if the driving was discontinued. In general, when
bearing is being determined by penetration, it is prudent to allow a minimum of 20 to 30
blows (2 or 3 measurements) at what appears to be practical refusal to occur before
discontinuing driving on the pile. Record the final 3 to 5 measurements in your pile
driving data. If any doubt exists, have the pile foreman drive 10 more blows to ascertain
the accuracy of your reading.
A word of caution should be interjected at this point concerning overdriving the piling.
Be aware that practical refusal may occur suddenly and when penetration is zero and
absolute refusal has been obtained, continued driving may result in damage to the piling.
This damage is characterized as follows: in concrete pile – cracking, splintering and
broken pile; in steel pile – buckling of the pile, turning of the pile in the leads and
warping of the length of the pile projecting above the ground line. Caution should always
be exercised in pile driving, and relative comparison in driven length to expected length
of piling to be driven in the same locations.
The length of piling required to obtain proper penetration and bearing is the responsibility
of the contractor. The Bridge Engineer will authorize length for precast concrete pile
with a one foot shorter pile allowed in length tolerance. Steel shell pile and structural
steel pile length will be the contractor’s responsibility. Under normal conditions, a small
surplus length of pile can be expected in each length driven. This cutoff section will be
removed by the contractor to the elevation designated by the Resident Engineer. All
piling will be cut off square at the given elevation, No deduction will be made in payment
for cutoffs on precast concrete pile. A deduction in length will be made for cutoff of steel
shell for cast in place pile, structural steel pile and test pile and this cutoff length should
be shown in the pile driving data file.
Occasionally, the opposite condition will occur, and the piling will have to be extended to
obtain the proposed bearing. When this condition happens, a splice will be required.
Because of the undesirable nature of the splice in a bearing pile, this condition should be
avoided and every attempt made to drive all piling full length. If necessary, the Resident
Engineer should contact his Regional Project Engineer Supervisor if it appears that the
pile length, as furnished, is insufficient, and the contractor will be required to provide a
new length for use.
705.4 SPLICES
Additional spliced pile should be shown in the pile driving data file, as well as any
resulting cutoff upon completion of pile driving.
157
Original Date: 1/3/94
Revised Date: 05/27/16
705.5 FALSEWORK PILING
When falsework in involves placing piling, the piling must be driven to the required
bearing. All requirements for pile bearing footings will apply. The actual placing of
falsework will be done in accordance with the plans utilizing material which is both
sound and adequately straight to hold the form work to the proposed line and grade with a
minimum of shims or blocking. When camber is to be placed in a structure supported by
falsework, care should be taken to maintain direct bearing at all points of loading. A
minimum of ¼ inch compression can be expected when the structure is fully loaded, this
should be incorporated in the camber when placed. In almost all cases, screw jacks or
turnbuckles will be used to provide a means of adjustment for the maintenance of an
established grade for the structure. When grade is a consideration in the final product,
the contractor is required to incorporate a means of monitoring settlement in the structure
and experienced personnel to monitor and correct for any resulting movement. Probably
the simplest and most often used method is the “tattle tale”. A “tattle tale” is a device
composed of two vertical members, on affixed to the structure (usually at mid-span or a
point of known elevation) and the other mounted to an unmoving object or the ground.
The two members should be overlapped and separated horizontally by ⅛ to ¼ inch. A
mark should be placed on the fixed member under unloaded conditions and checked
periodically during the loading process. By monitoring the downward movement of the
free member, an accurate determination of settlement can be determined and elevation
adjustments can be made. The Resident Engineer should personally check these devices
during and after a pour until the concrete has taken an initial set. When friction collars are
used on columns, a mark at the base of the friction collar will indicate any movement in
the device.
705.6 PILE PAYMENT
Payment for bearing pile of all types will be to the nearest foot, which means individual
lengths should be recorded to the nearest tenth of a foot. Actual in place measurement
will be made for all types of piling. When pile splices for precast concrete pile are
allowed, and additional 8 feet of pile length will be paid per pile extended.
706
SUBSTRUCTURAL UNITS
Because of the variety of substructural units constructed in relation to bridge and culvert
construction, a generalized review of construction procedures and problems will be
discussed. The Plans and Specifications will provide both specific and general
requirements for construction. A very important source of information containing
requirements for construction will be found in the construction notes incorporated in the
Bridge and Culvert Plans. These notes will point to specific problem areas designated by
the designer and provide acceptable solutions in the resolution of these areas. Deviation
from the proposed method of construction outlined in the construction notes should not
158
Original Date: 1/3/94
Revised Date: 05/27/16
be allowed unless approved by your Regional Project Engineer Supervisor or the Bridge
Engineer.
706.1 FORMS
All footings must be formed. Where footings are formed on cast in place piling, the pile
must be at least 12 hours old. When footings are to be keyed in rock, the area below rock
line may be neatly poured and need not be formed. All form lines are to be true to line
and grade and are to be adequately braced. Simon or combination metal-wood forms
may be used on footings which will not be exposed if approved by you Regional Project
Engineer Supervisor. Quantities of concrete for payment will be determined by stated
plan dimensions and not actually formed dimensions, unless and authorized dimension
change has been made.
706.2 COLUMNS
Forms for columns in intermediate bents will usually be of metal or sonotube (fiber tube).
When metal forms are used, adequate bracing will be most important. A means of
adjustment must be incorporated into the bracing (turnbuckle, tension wire, etc.) to
maintain the forms in plumb during and after the pour. When fiber tubes are used above
ground line, they must be of waterproof construction and leave no seams in the finished
surface. When fiber tube is used from 6 inches below ground line on down, they may
leave seams on the finished surface. Fiber tube must be thoroughly braced to prevent
distortion during the concrete placing. Alignment and plumb should be maintained at all
times by adjustment devices on the bracing.
706.3 INSPECTION OF FOOTINGS AND COLUMNS
Footings should be checked for clean vertical form walls, soundly braced and on line.
Center of footing should be marked by a nail in the end form and at intervals which can
be checked by transit set on a control point establishing a true line to another control
point.
Elevation should be controlled by formed top edge set on grade or by chalk line or grade
nail line to establish the desired elevation line.
Columns should be checked for alignment both with the stationing of the bridge and at 90
degrees to the stationing.
The exact placement of each column should be set by and checked with a transit sitting
on a control point and shooting to a central point to produce a straight line. Vertical
plumb should also be checked on each column. The best method to accomplish this
checking is by attaching a plumb bob with a long string to a nail placed on line at the top
of the form work. The plumb bob is then suspended to a hub or mark at the base of the
column, also on line. Any variation from true alignment or plumb will be shown as the
159
Original Date: 1/3/94
Revised Date: 05/27/16
plumb bob strays from the nail or mark. By placing two plumb bobs at 90 degrees
separation, the exact alignment and plumbness can be maintained for each column.
706.4 ABUTMENTS AND CAPS
The cap associated with round columns will probably incorporate the use of falsework as
an integral part of the construction. Normally, friction collars will be installed on the
completed column and will form the bearing-load transfer device for the cap form work.
On those structures where falsework provides the structural support for the substructural
or superstructural units (until a required compressive strength is obtained in the
reinforced concrete), a detailed set of falsework plans signed and sealed by a Registered
Professional Engineer, must be submitted approved before any work may commence.
Special attention should be paid to any structural beams proposed for use. Adequate
beam size, flange crippling and overturn of the beam are often neglected by the
contractor in favor of utilizing available or salvaged materials.
706.5 FORMING
Material - Forms shall be composed of sound, durable lumber. Normally, all forms will be
composed of 1 inch minimum thickness lumber or 5/8 inch minimum thickness plywood.
Reuse of forms is totally dependent on the condition of the lumber and the location of the
form work. Forms which will produce an exposed surface shall be free of open knotholes
or other surface defects which will mar the finish of the concrete. All forms (except
composite forms) shall be oiled before use with a clear paraffin base oil. Simon forms or
combination forms must be lined when approved for use on exposed surfaces. Full 4 x 8
foot sheets of 3/8 inch minimum thickness plywood will be used. Cutting of full sheets
will only be allowed when shape or size requirements dictate. For use on unexposed
surfaces, these forms need not be lined. When Simon or combination forms are used for
the interior barrel walls of box culvers, the lining requirement will be waived except for
the first four feet inside of each headwall. When curved surfaces are incorporated into the
structure, form liners will be required. The liner may be either ¼ inch minimum thickness
plywood or composite board (masonite) blocked as necessary to produce the proposed
shape. All exposed edges on structures are to be constructed to produce a beveled surface.
This is to be done by using ¾ inch beveled strips composed of wood or a rubber-based
material (curved edges only) which is commercially available. These strips must be
securely nailed to the forms and should be included in all construction joints. When used
in conjunction with a construction joint, a doubled beveled strip will be required to produce
a V-shaped indention into the two concrete masses. When a rustification joint (drip strip)
or special details are to be incorporated into the finished surface, the necessary shape
producing items will be firmly attached to the forms.
Structural Adequacy - All forms are to be structurally sound, mortar-tight and properly
braced to prevent distortion or bulging when concrete is placed. Various forming
systems may be used on each project; however, in all cases the forms must be designed to
maintain a fluid pressure of 150 pounds per cubic foot. In addition, a live load of 50
160
Original Date: 1/3/94
Revised Date: 05/27/16
pounds per square foot for horizontal surfaces and 30 pounds per square foot for vertical
surfaces (for impact and vibration) must be included in the design calculation. On very
large retaining walls, abutments or other structures the contractor may be required to
provide forming plans for review. Generally, forms will be made up as panels which will
be held to the proper alignment and grade by a system of braces and walers utilizing a
metal tie from form to form. The spacing of metal ties, the size of the walers and the
spacing of walers and braces will all be determined by the contractor but should be
checked by the Resident Engineer. The contractor should place additional bracing as
requested by the Resident Engineer. In the event that a form should buckle or deflect, the
pour should be stopped until such time as the affected area can be shored up with
additional bracing to re-establish the proper alignment. Panels should not be held in
place by devices which penetrate previously poured concrete or by kickers or braces
which impose a load on other structural members. Metal ties and spreaders used to hold
the forms to the correct alignment and the proper location should be of one piece
construction, unless otherwise approved and so constructed as to be capable of being
broken off a minimum of 1 inch below the surface (snap ties). Under no circumstance
should wire ties or pipe spreaders be allowed in structural applications, nor should pull
through systems be allowed which require removal of rods or bolts by pulling them
through the concrete. Collar systems for cap construction which utilize other than friction
or falsework properties should not be allowed (Axis Rod System).
On massive abutments and retaining walls, a bolt through system may be used, if
approved by the Bridge Engineer or your Regional Project Engineer Supervisor.
Normally, this system will use bolts of various lengths which screw into a smooth
extension rod which can be withdrawn after the concrete has attained the proper
compressive strength. This system is secured by a camlock arrangement at the waler.
(Shebolt and Camlock System). The Snap Tie System mentioned above is secured by two
methods. In the first, the snap tie protrudes between two walers and is held by a slotted
wedge which secures the snap tie on each end. In the second method, the pencil rod is
held on one side by a device called a cathead which secures the formed end of the device
and the other end is secured to a vertical support (stiff back) by a clamping device called
a rod tightener. With pencil rods, there is no break back; therefore, pencil rods are rarely
allowed. All of these devices rely on tension to work properly and should be properly
secured as concrete is placed in the forms. Temporary spreaders may be used to maintain
the proper form width; however, they should be withdrawn as the concrete pour
progresses.
Care should be taken to ensure their removal during the pour. Under no circumstance
should any solid wooden substance be left in the form work as the concrete is placed.
Wood in concrete will swell and will crack the concrete before the required compressive
strength is attained.
706.6 BOX-OUTS
161
Original Date: 1/3/94
Revised Date: 05/27/16
When pipe openings or other box-outs must be placed in any form work, a Detail
Drawing will usually be provided in the plans. This practice is common in box culvert
and retaining wall construction.
The box-outs must be firmly held in place and internally braced to withstand the required
fluid pressure loading previously stated. Braces or struts which will extend through the
exposed concrete will not be boxed out unless approved by your Regional Project
Engineer Supervisor. This approval will also be required when the contractor requests
the use of “windows” or closeable opening in the form work to aid in concrete placing on
tall structures; however, clean out opening at the base of any form work will be allowed
before the actual concrete placing commences. These openings will be firmly and
completely closed and will present a smooth surface with the inside form work.
Falsework and form removal will in most cases by governed by compressive strength
requirements for the concrete placed with them. A table of compressive strength
requirements for form removal is contained in the Specifications. Falsework and forms
under substructural members should be released in such a manner as to permit the
concrete to gradually and uniformly take the stress induced by its own weight.
706.7 WEEP HOLES
Weep holes should be of the size, shape and slope shown on the plans. A check should
always be made to determine that the proposed weep hole elevations will, in fact, be
above finish grade. Weep holes must be positively secured within the form work to
ensure no movement or floating during the concrete pour.
707
REINFORCING STEEL
When the form work is in place, either completely or partially assembled, the reinforcing
steel may be placed. Reinforcing steel will always be enumerated on the bill of
reinforcing sheet, and the numbers of bars and locations will be shown on the structural
plan sheets and structural cross sections.
The bill of reinforcing steel sheets should contain the reference mark of the bar, bar
location, number of bars required at that location, shape number or shape designation,
bending dimensions and/or series cutting dimensions, nominal length, actual length and
weight per bar type designation. In addition, general and specific bending notes and
requirements should be shown. Some bill of reinforcing steel sheets may also contain
specific detailing practices to be followed in the fabrication of the reinforcing steel along
with shape details for specific applications and special notation for epoxy coated
reinforcing steel.
In general, the bar list will be divided into specific substructural units. Each bar
designation should follow a logical sequence of numbering which will show bar size, bar
designation and similarity of bars per structural unit.
Example:
162
Original Date: 1/3/94
Revised Date: 05/27/16
Bar Designation
6-A10 - #6 Bar Size, Location A, Unit 10
6-A11 - #6 Bar Size, Location A, Unit 11
4-A12 - #4 Bar Size, Location A, Unit 12
The designation shows that the bars in question are in different substructural units and
differ in size but all appear in the same location within the footing. The shape of the
various bars should be shown and should be checked for adequate bar laps, clearance and
dimensioning. When a series of the same type of bar with uniformly increasing
incremental length are specified for use, the beginning and ending lengths should be
checked as well as the increment of increase in length per bar. For temperature bars, and
unless otherwise shown on the plans, bar laps will be considered to extend 24 times the
diameter of the reinforcing steel bar past the splice point. As a final point to be checked,
the actual overall length of the bar, including all bending allowances and splice lengths
(required in the plan only), should be calculated per each bar. By computing the bar
lengths required, the individual, unit and total reinforcing steel weight for the
substructure may be computed. As a theoretical weight, this computed number may vary
from the actual scale weights the contractor may request payment for; however, payment
is always made on the basis of the computed theoretical weight to the nearest 10 pounds.
The weights per foot length can be obtained from a variety of sources; however, the
attached ASTM bar weights and sizes are accepted as accurate.
TABLE 707 - DATA ON STANDARD DEFORMED BARS
Nominal Dimensions – Round Sections
Bar Designation
Mass per Unit Length
Nominal Diameter
Nominal Area
Imperial
Size
“Soft”
Metric
Size
(lb/ft)
(kg/m)
(inch)
(mm)
(inch²)
(mm²)
#2
#6
0.167
0.249
0.250
6.350
0.05
32
#3
#10
0.376
0.561
0.375
9.525
0.11
71
#4
#13
0.668
0.996
0.500
12.700
0.20
129
#5
#16
1.043
1.556
0.625
15.875
0.31
200
#6
#19
1.502
2.240
0.750
19.050
0.44
284
#7
#22
2.044
3.049
0.875
22.225
0.60
387
#8
#25
2.670
3.982
1.000
25.400
0.79
509
#9
#29
3.400
5.071
1.128
28.650
1.00
645
#10
#32
4.303
6.418
1.270
32.260
1.27
819
#11
#36
5.313
7924
1.410
35.810
1.56
1006
163
Original Date: 1/3/94
Revised Date: 05/27/16
The following areas of inspection will be required for fabrication, storage and installation of
reinforcing steel:
(a) Fabrication - Reinforcing steel for use in structural applications will be either
deformed Billet-Steel (ASTM A615), (ASTM A616) or Axle-Steel, deformed, (ASTM
A617). Normally, reinforcing steel for structural applications is of these three types
(with a low alloy material being infrequently used but not adopted by the general
specifications). Two grades of minimum yield strength steel are used in structural
applications, namely Grade 40 and Grade 60. These grades will be specified in the
Contract Bid Item and must be used in the indicated structural areas. Grade
distinction is shown in one of two ways on the individual reinforcing steel bars. The
line system incorporates an additional line called a grade mark adjacent to the
identification code and through at least five deformations between the main ribs on
the bar to indicate Grade 60 steel. In the number system, the Grade 60 steel is
identified by the number “60” which appears as a grade mark in the identification
code rolled into the individual bar’s surface. In either system, the absence of the
grade mark will indicate Grade 40 steel.
Regardless of grade, all reinforcing steel is required to carry an identification code
on each bar which will indicate the following:
(1) Production mill.
(2) Type of steel used (-N- represents new billet, -A- represents axle, -I- represents
rail and –W- represents low alloy).
(3) Grade mark (number system).
A check of samples and field material should be periodically made for compliance
and proper placing of required yield strength material. Fabrication of reinforcing
steel is normally done at plants designed for this purpose. Bending of reinforcing
steel should be done by mechanical means and without the use of heat. Field bending
of reinforcing steel should be done only when approved and without heat. Cutting of
reinforcing steel should also be limited.
(b) Storage - On-site storage of reinforcing steel is a common requirement on most
construction projects. While it may seem ridiculous to state, the reinforcing steel
should be placed out of the way of other construction. Repeated moving of
reinforcing steel will result in bent and unusable bars. The reinforcing steel should
be clearly marked and securely bound into groups by reference mark as correlated to
the bill of reinforcing. Reinforcing steel should be unloaded using slings and
equipment with the capacity to lift and place the load as required. Under no
condition should reinforcing steel be dropped or dumped from the transport truck.
The reinforcing steel should be placed in a storage position off the ground, properly
164
Original Date: 1/3/94
Revised Date: 05/27/16
supported and arranged in sequence for use. Concentrated loading of falsework by
spot placing of reinforcing steel should be avoided.
(c) Installation - Reinforcing steel should be clean when placed. All mud, mortar,
concrete and heavy rust should be removed from the reinforcing steel before placing
in the forms. Reinforcing steel should be securely held in place and solidly supported
to prevent movement during the concrete pour. In substructural units, the reinforcing
steel should be firmly secured by a wire tie at every other bar crossing or closer.
This is often referred to as a “50 percent tie” and will be randomly done if inspection
is lax. The intent is for a specific pattern of ties to be established with no two
adjacent bars untied in any direction.
In almost all application it will be necessary to support the reinforcing steel to obtain
the proper clearance. In footing pours, metal legs, chairs or cement blocks may be
used. If bar chairs or legs are used, they must be securely tied and must be
structurally adequate to support the total weight of the reinforcing steel without
spreading or otherwise being displaced. Cement bricks may also be used to support
reinforcing steel, but wood, standard or ornamental brick should not be allowed for
use. In columns, end bents and intermediate bents, reinforcing steel should be
supported on bar chairs. In a bridge deck or box culvert pour chairs supporting the
upper mat of reinforcing steel should not be allowed to be placed on the lower mat of
reinforcing steel, but should be of proper size (height) to extend down to the framed
decking. Chairs are made of heavy gauge wire or #3 and #4 reinforcing steel bars,
and are normally placed a maximum of four foot on centers. Chairs are available in
any height desired (usually ½ inch increments) and are plastic coated and tipped
where the ends of the chairs will be exposed (as in intermediate cap). Larger chairs
normally used in box culvert applications are often called standees and are
fabricated as needed by the steel fabricator. As a result, the weight of the standee is
often included in the delivered weight total of all the reinforcing steel which makes
the contractor question the original computed weight total contained in the plan
quantities. Since standees and chairs are “No Pay” item, no basis for payment exists.
Chairs may also be used to obtain side clearance in intermediate caps or end bents,
wingwalls, etc. As previously stated, when continuous reinforcing is place from the
footings to the cap, care must be made to insure proper bar placement and alignment.
Reinforcing steel placed in pedestal pile will often present this problem, and careful
attention must be paid to alignment of the vertical bars where they intersect the
horizontal reinforcing steel in the bottom of the cap.
Each and every bar placed must be checked for correct size, spacing location and
number required as well as grade required. It is safe to assume that all steel
reinforcing will be improperly placed by the contractor unless the iron worker
foreman can prove otherwise. Normally, the iron worker foreman will set up a
template of bar locations on a major longitudinal bar which will span the length of
the structural member. The location of all transverse bars will be marked on the
165
Original Date: 1/3/94
Revised Date: 05/27/16
template bar, and the work will proceed based on the assumption that the original
template layout is correct. Should any error occur in the original layout, it will
usually be faithfully reproduced in the completed work. For this reason, all layout
work must be consistently and concisely checked in the following manner:
(1) Clearance - Maintaining the proper clearance is always a major problem.
Clearance is always assumed to be 2 inches otherwise shown on the plan and is
always measured from exposed face of concrete to the front face of reinforcing
steel.
When necessary, chairs or spreaders may be used to obtain the needed clearance;
however, spreaders or blocking must be removed as the concrete is placed with no
displacement of the steel occurring. Long diameter steel is especially hard to hold in
place and should be checked often for displacement. A positive means of holding the
reinforcing steel in place must be utilized for the following applications.
(1)
(2)
(3)
(4)
Tall walls or enclosed abutments.
Battered walls with battered reinforcing steel.
Curved ends on intermediate caps.
All columns.
Positive means of securing the reinforcing steel will include the following:
(1)
(2)
(3)
(4)
(5)
Anchors and tiebacks to existing reinforcing steel.
Spreaders or wedges withdrawn as the concrete is placed.
Additional dowels for support and tie off.
Plastic tipped chairs.
Tie off to hoisting equipment.
707.1 INSPECTION
As mentioned above, a template is normally used to position the reinforcing steel. The
template should be marked with kiel to denote bar positions. Reinforcing steel bar
locations should be measured and marked from a discernable reference point such as
centerline or a working line. The entire length of the reinforcing steel in the structural
member should be laid out with particular attention paid to bearing seat locations and to
bar locations which will splice into another pour above a construction joint. Any
adjustment in bar position or spacing should only be made by the Resident Engineer.
Common errors and point of inspections are as follows:
(a) Reinforcing steel in series may have incremental length changes which are only one
to two inches in variation. Such bars are often improperly installed. All bars in
series should be laid in increasing length before installation begins to obtain the
proper sequence of placing.
166
Original Date: 1/3/94
Revised Date: 05/27/16
(b) On abutments and intermediate bent caps, roadway cross slope is often obtained by
placing steps in the top surface of the structural member. When this is the case, these
points of elevation change should be denoted and the reinforcing steel positioned in
accordance with these elevations.
(c) Reinforcing steel placed so as to protrude through a construction joint and into
another pour should be checked not only for the initial pour, but alignment should
also be checked in the subsequent pour as well. When reinforcing steel is to be
lapped for a splice at a construction joint, a check of elevation should be made to
determine if the tails of the upper splice bars will protrude into the point below the
construction joint. Should this be the case, the field splice will have to be made
before the initial pour is made. In wingwalls, this may apply to horizontal reinforcing
steel as well.
(d) Where concrete beams are to be placed and poured into the backwall of the
abutment, the reinforcing steel should be checked for position to allow adequate
room for the beam to be set in place. This is especially important when the beam is to
be skewed to the abutment or bent. Reinforcing steel bars which will project into the
backwall from a level below the construction joint at the bearing seat should be
moved if necessary to provide adequate room for setting the beam in place. Care
should also be made to properly align the reinforcing steel at the bearing seat to the
proper skew and spacing to provide for an even loading at this point.
(e) All reinforcing steel must be secured in place. Unsecured steel bars (floaters) are not
to be allowed in any construction. One area in which this commonly occurs is where
the wingwall joins the abutment. Because of the eccentric loading in this particular
area, additional reinforcing steel will follow the skew between the abutment and
wingwall, and the spacing will often not match the spacing found in either the
wingwall or abutment. When this occurs, additional steel bars may be required to
support the designated reinforcing steel and provide a properly tied connection.
(Note: It may be necessary to place these bars between the abutment and the
wingwall as the steel for the abutment is being set but before it is securely tied in
place.) Because of the unusual shape of these bars, they are often hard to place when
the structural member is already tied together and the wingwall steel is being set.
(f) When reinforcing steel is placed in a battered wall, it will be necessary to ensure that
the splice bars in the footing are set at the proper angel to provide the proposed
batter. This check can best be accomplished by using a guide cut to the proposed
inclination. The use of an acetylene torch to aid in bending the splice bars to proper
angle shall not be allowed. A guide set at finish elevation of the footing should also
be used to check for clearance when the forms are set in place.
(g) Often, when culvert walls are being poured, the reinforcing steel will be positioned by
using an overhead template composed of a 2 x 4. When this method is used, the 2 x 4
167
Original Date: 1/3/94
Revised Date: 05/27/16
should be soundly braced and so constructed as to be able to carry the weight of the
reinforcing steel. All tie offs to the 2 x 4 should be made above the construction joints
so as not to extend through the finish face of the wall.
(h) When reinforcing steel rods are to project through a header, sufficient room should
be allowed for a splice, if necessary. The header should be sufficiently braced so as
to hold the reinforcing steel at the proper elevation and alignment. Reinforcing steel
rods and smooth slip dowels are not interchangeable.
(i) Where splices are made in the horizontal reinforcing steel of retaining wall or box
culverts, they should be staggered as to not allow any two splices to be in the same
vertical plane.
(j) When snap ties or she bolts, etc. are used in forming for the structural member,
alignment problems will occur. The reinforcing steel should not be moved to
accommodate these forming devices, nor should the reinforcing steel be tied to or
supported by these devices.
It is not uncommon on larger concrete pours for the Contractor to order additional
reinforcing steel to be used as bracing and to facilitate in maintaining proper clearance.
This extra reinforcing steel belongs to the contractor and should be disposed of at his
cost. Only that reinforcing steel specifically called out on the plans and enumerated on
the bill of reinforcing steel sheets should be included for payment.
708
PLACING SUBSTRUCTURE CONCRETE
708.1 TEMPERATURE RESTRICTIONS
Cold Weather Placement - Superstructure concrete is not ordinarily placed under winter
conditions. Substructure units and superstructure units, if placed, must be protected by
housing and heating or insulation. The principal inspection problem is to assure that
uniform heat is maintained through the enclosure and that proper moisture is provided.
Sometimes concrete is subjected to sub-freezing temperatures through failure of heating
systems, wind damage to housing, etc. If there is any evidence that the surface of the
concrete froze, the concrete should be rejected. Any violation of specification
requirements should be documented, and the Resident Engineer and the Regional Project
Engineer Supervisor should recommend appropriate action to the Highway Construction
Engineer if the situation does not seem to justify outright rejection.
The use of insulation with forms for the protection of concrete does not constitute a
waiver of the requirements of the Specifications for protecting and curing concrete in
structures. All concrete, such as wingwalls, backwalls, etc. having a thickness of 12
inches or less will require the addition of housing and heating to supplement the
insulation in severely cold weather. In general, this sections for which insulation is not
efficient are considered to be those which have less than 0.02 cubic yards per square foot
168
Original Date: 1/3/94
Revised Date: 05/27/16
of surface area. Securing the proper temperature in concrete is dependent on the ratio of
the volume of concrete to its surface area and the differential in temperature between
each side of the insulation.
Some important points to consider in the use of insulation are as follows:
(a) The contractor should provide a sufficient number of thermometer wells to provide a
check on the concrete surface temperatures.
(b) Concrete poured in moderately cool weather can develop excessive temperature, and
it is occasionally necessary to loosen the insulation to balance the temperature rise.
(c) In severely cold weather, to prevent the conduction of cold by the protruding
reinforcing steel, it may be necessary to provide supplemental heat at critical points.
(d) Care should be taken to check the temperature periodically at critical points until the
concrete has reached its required strength.
(e) The use of a maturity meter may help with access to areas without having to remove
the insulation or housing and to record temperatures when inspection personnel are
not able to be present. Check with the Materials Lab as to the availability and use of
the maturity meters.
708.2 FORMS AND CONCRETE
Before any concrete may be placed, the inside of the forms should be checked for debris.
Mud, wood, wire, nails, etc. must be removed. On all faces, a final check for clearance
should be made, and any tie wire protruding into the clearance zone should be removed
or bent back beyond the two inch limit. The forms should again be checked for structural
adequacy, tightness of joints, cant strip, etc. and, if approved, the concrete pour may
commence.
Concrete to be placed in a structural unit must be tested in accordance with the procedure
outlined in the Section 1000, Material Testing, of this manual. No concrete may be
deposited in the forms until the slump and air content are within the prescribed limits and
a consistent product is being provided.
Under normal conditions, concrete will be placed in dry forms with little or no water
present; however, when permitted by the contract or approved by your Regional Engineer
Supervisor, concrete may be placed under water.
In order for this placing to occur, the following conditions must be met:
(a) The water must be still, no visible current.
169
Original Date: 1/3/94
Revised Date: 05/27/16
(b) No vibration or moving of the concrete will be allowed.
(c) Seal concrete will be used regardless of specified class of concrete and with 10
percent additional cement included in the mixture.
(d) The concrete will be placed by either a tremie having a diameter of at least 10 inches
or bottom hump bucket with a minimum capacity of 1/3 cubic yard.
Concrete will usually be placed in substructural units and inspected by the following
procedures and in accordance with the following requirements:
(a) Concrete will be placed on a firm, stable base in the footing. When deemed
necessary, undergrading of the footing subgrade and backfilling with rock to reestablish the subgrade will be performed. Payments for this operation will be based
on the prevailing conditions and whether the unusable subgrade was a direct result of
the contractor’s negligence. When payment is to be allowed, the existing provisions
for overrun in structural excavation as a Contract Item will apply. Should no
structural excavation item appear in the contract, payment will be by agreed price.
The quantity will be by measured volume. Backfill will be paid be agreed price or
may be covered in the Job Special Provisions. When an extensive amount of
undergrading and backfilling will be required, as a box culvert floor, an agreed price
for Class III Excavation will be obtained as well as for backfill. In most cases,
backfill will consist of 2 to 6 inches clean stone choked with a minus stone. The
contractor always has the option to pour a concrete work pad at any abutment to
avoid unstable subgrade conditions due to moisture.
(b) Concrete may be conveyed to the point of deposition in a variety of ways. The most
common is the use of chutes to transport the mixture. Chutes used to convey concrete
must be either metal or metal lined. Because of problems with segregation, concrete
may not be dropped more than 5 feet vertically. This provision does not apply when
concrete is being deposited in a pneumatic caisson. When long chutes are to be used
and a velocity problem will occur at the point of deposition (which will place undue
stress on the form work) the contractor must reduce the velocity of the concrete by
using baffles, chokers or switchbacks in the chutes. When tremies are to be used to
deposit concrete, they should be of a diameter which will convey the concrete away
from the hopper at a sufficient rate to prevent backup and overflow problems.
Increasing the slump of the concrete to increase the flow should be discouraged and
prevented above the maximum slump or water cement ratio. When concrete is to be
deposited using a vertical tremie, baffles should be placed in the tremie to reduce the
rate of movement of the concrete.
708.3 PUMPING
To facilitate movement of the concrete, all tremies and chutes should be washed with
water prior to placing any concrete. When concrete is to be placed by mechanically
170
Original Date: 1/3/94
Revised Date: 05/27/16
applied pressure (pumping), several factors must be considered. First, the Contractor
needs to submit and have approval of a concrete mix design suitable for the pumping
operations Secondly, the equipment must be checked for pumping capacity per hour and
suitability for use on the project. Also a backup system must be provided in case of
mechanical breakdown.
During the actual pumping sequence, the following points of inspection will apply:
(a) The initial material to be pumped through the machine and lines will be a cement
slurry which will prime the machine and lines. This slurry should be discharged
outside the forms until fresh concrete has filled the system. The designated location
for quality control sampling to determine air content and slump is the point of
discharge from the end of the concrete pump. After the slurry is discharged enough
concrete can be placed, as such, that it is accessible to the inspection personal for
testing. The pumping operations shall not start until the concrete mix has been tested
and approved by the Resident Engineer or other designated Inspection personal.
(b) Material not having the correct slump may be washed from the pump but must not be
placed in the forms. Water added to the concrete and used for washing of the hopper
should be strictly monitored and controlled.
(c) As the pumping proceeds and a consistent concrete is being placed, the pumping
pressure should be refined to provide a laminar flow in the hoses without
interruptions or air pockets. Too much pressure will result is segregation and
scattering of the larger aggregate. Because many of the newer concrete pumps have
articulated booms, it is possible to produce an airlock in the line which will stop the
flow of concrete. This usually happens when the boom is elevated and concrete is
allowed to gravitate backward in the hose when pumping is interrupted. When this
occurs, the boom must be straightened and the vacuum removed. Any interruption
which requires cleaning of the hoses should be done outside the form line, and the
concrete discharged should be considered contaminated.
(d) When delays in delivery of concrete exceed 45 minutes, the pump must be cleaned of
all concrete contained internally. The procedure is the same as at the end of the pour
with the last concrete being placed so as not to cause contamination of segregation of
the concrete mass. A sponge ball will be run through the evacuated lines and will
expel all residue concrete. The operation should be done well away from the form to
prevent splattering.
Regardless of the method of delivery to the forms, concrete should be placed in a
continuous operation and in such a manner as to uniformly load the falsework or form
work. On large abutment and retaining wall pours, the level of the concrete in the forms
should be brought up in controlled stages and should be kept roughly level as it is placed
in the following manner:
171
Original Date: 1/3/94
Revised Date: 05/27/16
(a) Uniformly vibrated from bottom to top by submerging the vibrator vertically through
the lift being placed and into the lift below to bond the interfacial surfaces.
(b) The vibrator should be kept vertical while being moved from place to place in the
forms, not dragged around in the concrete.
(c) The vibrator should not be left in one spot but moved continuously and should not be
used to move concrete within the forms.
(d) The vibrator should not be allowed to contact the reinforcing steel or the sides of the
forms.
(e) In corners and along the base of tall walls, vibration must be closely monitored to
prevent movement or bulging of the forms.
(f) Vibrators used in structural pours should have a minimum frequency of 4,500
impulses per minute.
The Resident Engineer should personally check the forms periodically during the pour,
specifically looking for movement of forms in corners, bulging of the forms, broken or
cracked walers or loosened form ties. Should any indication of a potential weakening or
giving way of the forms be found, the pour must be stopped until such time as the forms
are strengthened to withstand the loading and the proper line and grade are reestablished.
When alternating panels of a retaining wall are being poured, the Resident Engineer will
also have to check on the proper positioning of water stop, weep holes and expansion
material as the pour progresses. Water stop should be continuous and full length, firmly
held in place and the prescribed shape should be maintained while the pour progresses.
Gray sponge rubber expansion material should be full width with longitudinal splices
secured with either 10 gauge copper wire or 12 gauge galvanized steel wire which should
also project into the concrete and thereby provide a tight bond to the adjacent surface.
708.4 FORM REMOVAL
The final work to be performed on the substructural units following curing and form
removal is the patching of tie holes. Following the removal of the tie appurtenances, the
remaining hole should be filled with a 2 to 1 sand-cement grout mixture which has a nonshrink agent or has been allowed to stand for 45 minutes before placing to prevent
shrinkage. This will only apply to tie cavities in exposed concrete surfaces. Cavities in
backfill areas or unexposed areas may be sealed with a plastic mortar compound
(Sewertite).
709
TYPES OF STRUCTURES
172
Original Date: 1/3/94
Revised Date: 05/27/16
There are three types of bridge structures commonly built in St. Louis County. They are
structural steel girders, prestressed concrete girders, precast box girder/box beam.
709.1 STRUCTURAL STEEL GIRDERS
The structural steel girder bridge is commonly used on spans greater than 100 feet in
length or where limited height for the bridge is available. Its disadvantage includes
higher cost than prestressed concrete in less than 100 foot spans and more required
maintenance over the life of the bridge (painting).
Deck forming methods used in association with structural steel superstructure systems
include the use of needle beams, cribbing and jacks. Also in use are deck systems which
employ a sheet metal flooring which welds to the beams and a concrete or composite
concrete-steel mesh grid system. These systems are rarely designed or approved as an
alternate method. Regardless of the system employed, a continuously sealed, tight form
must be employed for the deck. As with other deck systems, haunching grades must be
computed and formed into the deck to obtain the proper deck grades. The method used to
obtain haunching will be discussed later.
Bearing Areas - Before any beam is set, the bearing assembly must be placed. Bearing
assemblies will be inspected for surface finish before shipment to the project. When lead
plates or preformed fabric pads are used as a part of the bearing assembly, they shall be
approximately 1/8 inch in thickness and ½ inch greater in perimeter dimensions than the
bottom bearing plate. When in place, the bearing assembly should make full contact with
the stringer or concrete surface. If the bearing assembly is not at the proper elevation,
steel shims may be employed to effect minor elevation changes. Grouting will not be
permitted. Shims will be full sized to match the bearing device and will be straightened
to provide a plane surface.
Anchor Bolts - The anchor bolts used to secure the bearing assembly may be poured
monolithically with the bridge seat, drilled in place or set in bolt wells. The plans will
normally denote which method is to be used. The diameter of the anchor bolt hole should
be large enough for placing of the bolt, with adequate room for grouting or epoxy
anchoring systems and centering of the bolts in the bearing assembly. When anchor bolts
are employed, the hole will be centered around the bolt location and of a sufficient size to
allow adequate grout to be placed to hold the bolt in the correct position and alignment.
Shear Connectors - Inspection of the field welded studs will require the following:
a) Visual inspection for cracks or breaks at the welded area and 75 percent weld collar.
b) Corrected stud height after welding.
c) At least 10 studs, but not less than 3 percent of studs per beam, shall be checked by a
bend testing. This will require hammering the stud not less than 15 degrees from
173
Original Date: 1/3/94
Revised Date: 05/27/16
vertical lengthwise to the beam and then checking for failures and the weld areas.
Test studs will be left in the bent position.
709.2 PRESTRESSED CONCRETE I-GIRDERS
The second form of bridge construction is the prestressed concrete I-Girder bridge which
is the type most commonly built by St. Louis County. The reason for this is its economy,
low maintenance and relative ease of construction.
Precast prestressed concrete I-Girders are fabricated using the same requirements as
specified in the precast box beams. Shop drawings are required and must be submitted
by the contractor for approval prior to the fabrication of the I-Girders. The I-Girders are
fabricated off site and inspected by the Materials Lab and shipped to the bridge site.
I-Girders are checked during fabrication for dimensional tolerances and casting defects.
The girders should be checked on the job for damage from handling and shipping
(chipped corners or edges on the concrete and chipped off epoxy from the reinforcing
steel). Cracks can sometimes be observed near the ends of the I-Girder; however, these
cracks are to be considered normal and are not a cause for alarm. The sharp ends of the
skewed deck beams sometimes break off during the stripping of forms and detensioning
operations and may be considered acceptable. The prestressing cable strands are bent up
and poured into the bridge superstructure. Girders will have a “Report on Precast
Concrete” that confirms to the Resident Engineer that the girders were inspected. Girders
will be numbered as shown on the framing plan. The I-Girders may have steel bearing
plates embedded into the bearing areas. Smooth troweled areas on top of the I-Girders at
the ends, center and quarter point are provided for taking grade shots for haunching. On
longer girders, these areas may be at tenth points.
Bearing Areas – The bearing area surface should be finished as specified in the Job
Special Provisions or as shown on the plans; however, immediately prior to pouring the
pile cap of abutment wall, the girder camber should be determined and compared to the
theoretical camber shown on the plans. If there is a difference, it should be determined if
the theoretical haunch height is large enough to prevent a negative haunch. If a negative
haunch in anticipated, consult your Regional Project Engineer Supervisor prior to pouring
the pile cap or abutment wall, for a possible need to adjust the bearing elevation. Always
check the bearing area elevation prior to placing concrete.
Either plain neoprene bearing pads or laminated neoprene bearing pads are normally
used. Check the plans for locations where premolded joint filler is to be placed.
Bearing pads and joint filler shall be adhered to the bearing seat, prior to the placement of
the girders.
Coil inserts are provided in the girders for the installation of the coil rods in the abutment,
diaphragms and intermediate diaphragms. Holes will be formed through the web of the
174
Original Date: 1/3/94
Revised Date: 05/27/16
girders for the placement of steel diaphragms, if steel diaphragms are required. During
the shop drawing approval process additional coil inserts may be approved for forming
accessories, pipe hangers, conduits, drain systems, etc.
A deck is then formed and poured on top of the girders according to the plans.
709.3 PRECAST BOX GIRDERS/BOX BEAMS
The third form of bridge construction is the precast unit. Shop drawings are required and
must be submitted by the contractor for approval prior to the fabrication of the box
beams.
Precast prestressed box deck beams are fabricated off site and inspected by the Materials
Lab and shipped to the bridge site. The shallower sections use round voids and the
deeper sections have box-type voids. Drain holes are provided for the voids. Be sure to
check that these holes are clear.
The prestessing strands will generally be cut off flush at the beams ends at the
fabricator’s, and the beam ends may be square or skewed.
Bearing Areas – the bearing area surface should be finished as specified in the Job
Special Provisions or as shown on the plans. The area should be checked for elevation,
and the final finished surface should be obtained by grinding. Normally, neoprene
bearing pads are placed under the bearing area, and the remainder of the bearing seat is
filled in with premolded joint filler. These are adhered to the bearing seat, prior to the
placement of the deck beam. There should be a fixed end and an expansion end of the
bridge. The expansion end neoprene bearing pad should be thicker than the fixed end
bearing pad.
Beam Placement – Vertical holes are cast in each end to allow for fastening the beam to
the abutment or cap, vertical holes are drilled after the beams are in place and anchor
dowel rods installed. Dowel holes are filled with an approved non-shrink grout. When
the girders are to be placed adjacent to each other from one side to the other there will be
horizontal holes cast into the beam for a transverse rod assembly to tie the beams
together. The size and location of the void through the beam for the transverse rods will
be shown on the plans and approved shop drawings. The location is typically at the midspan for the shorter beam spans and the ⅓ points (two locations per beam) on the longer
beam spans. The size, length and steel grade of the transverse rods will be shown in the
plans and specifications and the requirements for their installation will be covered under
a Job Special Provision. For the inside beams there will be two voids (transverse rods)
per location while the outside two beams will have one each. The placement of
transverse rods will alternate voids which allow the second beam to beam secured to the
first prior to setting the third beam, then then the third beam secured to the second beam
prior to setting the forth beam, and so on until the last outside beam is set in place.
Keyways will also be cast into the beams to allow for placement of non-shrink grout
between the adjacent beams. Two lifting loops are installed at each end of the beam and
175
Original Date: 1/3/94
Revised Date: 05/27/16
should be removed after the beams are in their final locations. Beams may have a curb
cast on them or may have inserts provided to bolt on fence posts, guardrail or forming
accessories.
A deck is then formed and poured or asphalt is placed on top of the deck beams
according to the plans.
710
DECK FORMING
710.1 HAUNCH
The purpose of all deck forming systems is to provide a supportive form work which will
allow for the construction of reinforced concrete pavement on grade and connected as a
structural component to the bridge or box culvert being constructed.
In bridges, this is performed by utilizing the haunch, the area directly over the beam, for
connection and elevation compensation. The haunch serves these two requirements by
performing the following functions:
a) All beams have the tendency to deflect under their own weight and from the load
applied to them. This deflection will vary from member to member depending on
beam size, span length and dead load applied and can be readily computed for any
point of the beam. Normally, the Construction Plans will contain a diagram of
computed deflection at the quarter points of the beam. These computed deflections,
when incorporated into the haunch, will theoretically produce the desired deck grade
when poured. Because of imperfections in the beams and bearing assemblies, these
deflection distances will not in reality provide the desired deck grade. For this
reason, a computed adjustment based on field survey information must be made to the
plan deflection distance.
b) Camber is incorporated into the beams as a way to counteract deflection. Camber is
the opposite of deflection but, because of many variable factors, cannot be assumed
to eliminate deflection as the beam is set and loaded. Normally, only a percentage of
the total deflection is removed by incorporating camber in the beam with the
remaining percentage to be taken up in the hauching. Field survey checks of grade
should be made on all cambered beams to determine the need for haunching.
c) Haunching also serves to rectify fabrication errors or extremes in tolerances for
structural items. On concrete precast beams, haunching is necessary because of
tolerances of up to 1 inch in camber between adjacent beams and as much as ½ inch
variation between actual and designed camber in the beam at time of release.
d) Haunching also provides a means for connecting the deck to the shear connector
system of the beam. As the haunching is directly over the beam, the added depth of
176
Original Date: 1/3/94
Revised Date: 05/27/16
concrete provides for clearance between the shear connectors and the bottom mat of
the deck reinforcing steel.
In order to compute the required depth of haunching for a steel girder or prestressed
concrete girder, these steps must be followed:
a) The centerline of bearing, quarter points and mid-span point of each girder in each
span must be marked and shot to determine the exact elevation at each point. (Check
plans for required additional points.)
b) The profile grade and station of each point must be computed for each girder. When
the bridge is skewed, the stationing must include an angular correction for the skew.
c) The deck grade at the specific point must be computed taking cross slope and
superelevation into account for each beam in each span.
d) The thickness of the deck should then be subtracted from the calculated top of deck
grade at each point to obtain the bottom of the deck grade.
e) The Theoretical Dead Load Deflection (given in the Bridge Construction Plan)
should then be added to the bottom of deck grade to obtain the correct grade.
f) The actual top of girder grade should then be subtracted from the bottom of deck
grade corrected for dead load deflection to obtain the haunch at each point.
g) The haunch grade should then be marked on the girder at each point.
If a negative haunch is obtained, adjustment to the profile grade of the entire deck may be
required. Check with your Regional Project Engineer Supervisor. A haunch of zero or
greater is acceptable. The above calculations should also be checked by another person
the help guard against errors. (Example: If the haunch condition indicates that a negative
0.03 is required, then 0.03 will have to added to every calculation for the entire deck.)
With the haunching grade, the carpenter can set the form work for the deck to the exact
grade at each point, and by using a string line, run from point to point, the form work can
be set exactly on grade for the entire deck. These computations should be recorded in the
Bridge files.
710.2 DECKING
Points of inspection for decking should include the following:
a) The decking must be positively anchored, free from dirt or surface defects. All
knotholes must be filled, all holes plugged.
177
Original Date: 1/3/94
Revised Date: 05/27/16
b) The decking must be firmly supported with no sagging or excess flexibility present.
c) Where deck drains are to extend through the decking, additional bracing and
stiffening of the area adjacent to the cutout will be required.
d) All decking should have tight joints (caulked if necessary).
e) Side and end forms must be cut full depth and to proper contour for roadway grade
and cross slope and must be plumb and securely braced.
f) Haunching grades must be set and the deck firmly blocked in position to stop all
vertical movement.
g) Tie inserts and supports for deck finish machine rail should be firmly set and
positively supported.
h) Coil ties at end of deck should be set for timber guard at approach slab when
specified. Drip strips should be in place. All exposed edges should be beveled.
i) Have forms been oiled prior to placement of reinforcing steel.
j) Have headers been checked for line and grade?
k) Did the contractor follow falsework drawings? Is method of bracing forms at
overhang satisfactory?
l) Will form ties break behind concrete surface?
710.3 REINFORCING STEEL
Reinforcing steel to be used in the deck of most bridge spans will be epoxy coated. The
main points of inspection will be the use of plastic coated chairs of the proper height
spaced to uniformly support the mat and correct bar spacing, 50 percent (every other
crossing) ties in lower mats with 100 percent ties in all upper mats. Splices are to be
avoided, except as shown on the plans, and are to be staggered. Reinforcing steel in
poured diaphragms and end bents should be placed first for convenience. When epoxy
coated steel is specified for use in the structure, care must be taken to ensure that all
coated bars are delivered at the start of bar placing. Bars which project from the
substructure into the abutment or diaphragms above the bearing seat must be placed using
a coated tie wire and should be protected from scarring or splattering with concrete.
Epoxy coated steel will be produced by placing an electrostatic spray or fluid coating on
uncoated reinforcing steel. The uncoated steel will be inspected by heat number and bar
size either at the point of origin prior to shipping, at the coating applicators prior to
coating or in the field after coating, utilizing sample bars furnished for this requirement.
178
Original Date: 1/3/94
Revised Date: 05/27/16
When inspection is performed in the field, any bar failing to pass will result in the
rejection of the entire lot of bars in that size. If retested, the same criteria will be used but
double the quality of bars will be tested. Failure in any test will cause rejection of the
whole lot of the same bar size. These inspections will be performed by the Materials
Lab, The Contractor should be advised and should provide additional reinforcing steel,
both plain or epoxy, for testing. The test bars should either be 2-three foot long or 1-six
foot long bars and clearly marked for each size and heat number being delivered for the
project.
Regardless of inspection, the contractor shall furnish a manufacturer’s certification and
certified test results performed by the applicator for quality assurance. Any material
which is damaged beyond acceptable repair at the project site shall be replaced at no cost
to the County.
When shipped, handled or stored, the epoxy coating is to be maintained undamaged. In
order to protect the coating, padded supports should be utilized during transport and
storage. Cloth or padded slings should be used to load and unload the material. When
placed, the reinforcing steel be set on plastic coated chairs and secured with plastic
coated tie wire. Every effort should be made to prevent rubbing or scratching the coating
especially at shear connector or deck drains. The entire surface of the in-place
reinforcing steel should be inspected for breaks in the epoxy coating prior to concrete
placing. Any and all breaks in the coating should be repaired with a suitable epoxy
material furnished by the supplier. A red or other highly visual marker should be used by
the Resident Engineer to mark all areas in need of repair. During concrete placing, care
should be taken not to strike the epoxy coated steel with the concrete vibrator. Special
rubber or foam rubber tipped vibrations are the used for this application.
710.5 BRIDGE CONDUIT SYSTEMS
Bridge conduit systems are of two types – those which pass through the deck and those
which are suspended from the deck. The through-the-deck system is usually composed
of a PVC conduit as is commonly used for traffic signal installation. When poured in the
deck the main points of inspection consist of properly supporting the conduit until the
concrete is poured, maintaining alignment and elevation while the concrete is being
poured and assuring access to the conduit by placing pull strings and installing mortar
tight connections. Support for the conduit and alignment and elevation control are
usually maintained by support chairs secured on line to the deck and spaced as required
to provide the necessary support and freedom from sagging while the concrete is placed.
Conduit should not by suspended from the deck reinforcing steel nor should the
reinforcing steel be relocated to facilitate installation of the conduit. A minimum number
of fittings for bends and conduit connections should be used. When used, the fitting
should be either glued or threaded to provide a mortar tight joint. Pull wires and other
means of access to the conduit should be placed as soon as possible after the concrete is
poured. Alignment and freedom from mortar obstruction in the conduit can be checked
by drawing a steel ball of smaller diameter through the conduit or by using compressed
179
Original Date: 1/3/94
Revised Date: 05/27/16
air to force a sponge ball through the embedded conduit. When required, junction boxes
should be installed plumb and square whether in the deck or in the parapet wall. Junction
boxes should be drilled and tapped for conduit connection and should contain waterproof
gaskets in the door to maintain dry conditions in the box. Excess wire should be coiled in
the junction box.
Suspended conduit systems generally employ a threaded deck insert onto which a support
bracket is attached. Points of inspection for such systems will entail checking for exact
spacing and alignment of each insert. The insert must be firmly connected to the deck,
and care should be taken when placing and vibrating concrete so as not to dislodge the
insert. The female end of the insert, if not coated, should be greased to prevent mortar
intrusion and build up in the threaded portion.
711
DECK POUR
711.2 FINISHING MACHINE
The deck finishing machine will, in general, be composed of a truss frame mounted on
vertically adjustable leg supports which will be supported by flanged wheels designed to
run on the guides or rails. Propulsion will be by electrically driven or hydraulically
driven motors which are capable of advancing each side of the machine independently.
The truss frame is composed of individual sections of various length which may be
assembled to provide for various widths of paving. Because each section is
independently added to the total machine length, it is possible to establish breaks in grade
which will affect the inner carriage rail upon which the strike off and finishing
mechanisms runs. This rail is adjustable in one foot increments for its entire length and
must be set to identically match the cross slope conditions of the deck. Under normal
conditions, setting of this inner rail will be accomplished after the machine is set on the
deck rails or guides and at or near operating height. A parallel graded string line must be
established uniformly above the inner rail (on some mechanisms, eyebolt will be in place
in the machine truss end sections for this purpose) and should include any breaks in grade
or parabolic rounding’s. When the deck pour extends beyond the centerline crown, it
may be necessary to break back the last truss section to obtain the desired cross slope past
centerline.
After setting the grade string a uniform distance above the inner rail, each segment of
inner rail must be adjusted to provide a graded rail having the desired cross slope a
uniform distance above the bottom of deck. When the pour width exceeds the centerline
crown point, a parabolic crown will have to be placed on the inner rail as it is impossible
to place a peak in the rail. Normally, this will involve a 4 foot increment of rail centered
on the profile grade and set by hand to match the capabilities of the machine. When the
rail is set, all securing nuts should be tightened and the machine truss section set in place.
For the most part, these crowns are fixed and cannot be adjusted into or out of crown as
the pour progresses.
180
Original Date: 1/3/94
Revised Date: 05/27/16
After the carriage is attached to the truss section by the inner rail, the machine should be
adjusted to operating height above the bridge deck. A check of deck thickness from the
finishing drums to the bottom of deck should be conducted at intervals across the entire
deck surface. Particular attention must be paid to deck thickness at each end header to
avoid striking or sticking on the header during paving operations. The easiest method
employed for checking thickness is to cut a gauge exactly the thickness of the deck and
place the gauge under the end of the finishing drum and deck. When properly adjusted,
the gauge will tightly fit in this space between the deck and machine. Deck thickness
should also be checked as the pour progresses to maintain required deck thickness.
Tolerances on thickness should be zero on the minus side and no more than ¼ inch on the
plus side. Because the finishing machine will travel longitudinally across the bridge
deck, variations in thickness due to skew angle and superelevation may be expected but
should be minimized. The finishing of the bridge deck will be performed by the
oscillation of the carriage suspended from the inner rails as the machine moves forward
on the deck. The length of oscillation is controlled by stops placed on the drive chain of
the carriage, and the interval of forward travel is controlled from the operating platform,
either manually or automatically. Forward travel should be in 3 to 6 inch increments
depending on the elevations control of the concrete placed in advance of the machine.
The actual finishing process is contained in the oscillating carriage. Deck elevation is
obtained by single or double strike-off augers which are mounted on the front of the
carriage. The rotation of the augers will effectively produce the desired finished grade
for the deck provided excessive amounts of concrete do not accumulate in advance of the
machine. The augers are adjustable vertically and should be set slightly higher (1/16 to
1/8 inch) than finish grade. Immediately behind the augers will be a single or double
drum rotating float which will consolidate and finish the deck at final grade. In order to
properly finish the bridge deck, the drum should maintain a slight volume of concrete or
mortar in advance of the rotation. This is achieved by raising or lowering the strike-off
augers as needed. When properly operating, the drums should produce a smooth surface
sealed deck uniformly on grade. If this is not the case, immediate adjustments must be
made to obtain the required result. Finally, attached to the carriage frame is a pan plate
drag float used as a secondary float for surface sealing.
711.3 CONCRETE FINISHING
Under normal conditions, the finishing machine will make only one pass over the bridge
deck; however, it will be standard procedure to check the bridge surface (full length) with
a 10 foot wide Cleveland straightedge, and any areas requiring revision must be reworked
with the finishing machine immediately. As in checking pavement, the straightedge will
be applied in overlapping intervals but must be brought from edge to edge of the deck by
using a work bridge which will span the pour. Following the straight edging operation,
the surface will be manually floated with a standard bull float and the surface texture
applied. Under normal conditions, a wire comb texture shall be applied. The striations
should be impressed approximately 1/16 to 1/8 inch into the surface and should be
uniformly applied with approximately 1 inch existing between passes. The surface texture
181
Original Date: 1/3/94
Revised Date: 05/27/16
must also be applied in a continuous movement from side to side of the deck pour,
preferably from a work bridge.
Edging of all exposed joints, including construction joints, will be required. Care should
be taken to assure the proper deck grade and drainage when deck drains or scuppers are
to be used in the deck. A 10 foot straightedge and level must be used to check the flow
line between deck drains and the gutter line on all bridge deck pours to assure drainage
on or over the structure. When vertical deck drains are employed in the deck, care must
be taken to assure correct placement of the drains. Because the drains will protrude
through the form work, a weak area will exist at each drain, and settlement may occur.
Settlement indicators or “tattle tales” should be checked throughout the deck pour with
elevation adjustments made as necessary. A final check should be made following the
finishing operation while the concrete is in a plastic state. Final deck grade adjustments
must be made prior to initial set in the concrete. A check should also be made of all
reinforcing steel which will extend from the deck for safety barriers, parapet walls or
other deck sections. Proper alignment, depth of cover, length of projection and locations
should all be checked and corrected while the concrete is in a plastic condition. A check
of continuity bar junctures should be made to assure exposure for future testing. Anchor
bolts and coil ties for construction anchors should be inserted following the finishing
operation.
711.4 CONCRETE PLACEMENT
Concrete will be placed by either bucket, mechanical pump or conveyor system.
Regardless of the system used to place concrete, the minimum pour rate must be
maintained. This minimum pour rate will normally be specified in the plans, and placing
will follow the sequence outlined in the plans. Any deviation from the proposed placing
sequence or minimum pour rate must be presented in writing for approval. The major
problem to be encountered by placing with crane and bucket will be maintaining the
required pour rate. The Resident Engineer should designate an inspector to log the
following information when pouring by this method:
(a) The time of the mixing operation at the plant. All concrete must be delivered and
discharged in one hour.
(b) Commencement of discharge should be noted for each truck, and only 15 minutes will
be allowed for discharge at each occurrence.
(c) As previously stated, the addition of water to the concrete at the deck pour site will be
governed by the water-cement ratio and by the number of mixing revolutions
available below the maximum allowance. The water-cement ratio should be stated on
the delivery ticket and, should never be exceeded by the addition of extra mixing
water. The number of mixing revolutions for the concrete is dependent on the size of
the mixer and cubic yard load transported. For loads in excess of 57.5 percent of the
182
Original Date: 1/3/94
Revised Date: 05/27/16
gross volume of the mixing drum or 91 percent of the rated capacity, a minimum of
70 revolutions will be required. For smaller capacity loads, a minimum of 50
revolutions will be required. For both contingencies, a maximum of 100 revolutions
will be the limiting factor. The addition of water will, therefore, be limited to one or
two times depending on load size as each mixing water addition will require 30
mixing revolutions.
Concrete placed by crane and bucket should be dumped as close to the reinforcing steel
as possible to avoid splattering, segregation and shifting of the reinforcing steel. All
concrete should be thoroughly vibrated and placed at or slightly above grade to enable the
finishing machine to accurately cut the deck grade. The use of a mechanical pump for
placing concrete on the bridge deck must be approved and, as a normal precaution, a
backup placing system will be required. Placing must be accomplished using nonaluminum parts or hoses and should be done in a continuous manner (delays will not
exceed 45 minutes). Concrete placed by conveyor should be monitored for loss of air
content and should be placed on the deck by means of a moveable hopper capable of
distributing the concrete evenly across the deck. The conveyor belts should be wetted
before placing concrete on them, and the deposition of concrete should be a continuous
operation.
Regardless of the method of placing of concrete on the deck, the pour rate and placing
schedule must be rigidly adhered to. Concrete should be placed to grade or slightly
above grade. Elevation should be controlled by using adequate labor to place and
consolidate the material ahead of the finishing machine. Care should be taken to
thoroughly vibrate the concrete so as to work the material completely around the
reinforcing steel and eliminate all honeycomb. Vibrators should have a minimum
frequency of 4,500 impulses per minute (with covered or rubber head when epoxy coated
steel is present) and should be checked with the “Vibratac” before each deck pour.
Normally, all vibration will be by handheld units, and a close inspection of all concrete
placed in advance of the finishing machine will be required. When diaphragms are
poured in advance of the deck, care should be exercised when vibrating the deck in this
location so as to produce consolidation of the deck concrete without undue disturbance to
the diaphragm.
When the aforementioned items have been completed and inspected, the deck may be
poured and finished. The bridge deck paving train will be mounted to run on rails or
guides which are supported on units designed to be situated on the deck beams either in
or out of the form line. When situated within the form line, the support unit will be twopiece, and the actual rail support unit will be removed from the concrete while still plastic
and resulting hole filled. Both rails will be established at a designated height above the
finish deck grade so as to parallel the profile of the deck. The designated height will vary
between machines, and the deck paving train will consist of a self-propelled, mechanical
finishing machine which will travel on the rails or adjustable guides.
711.5 IRREGULAR DECK AREAS
183
Original Date: 1/3/94
Revised Date: 05/27/16
Irregular deck areas and narrow areas such as sidewalks may be poured by hand methods.
Vibratory screeds will not be allowed for this work. Following strike off, the concrete
will be floated both longitudinally and transversely to produce the proper plane of the
deck. This type of deck finishing is also applicable to box culvert construction where the
top deck is not exposed. When the top deck of a box culvert is to be used as a part of the
traveled roadway, mechanical paving equipment must be employed, and the surface
texture should match the roadway texture. The contractor must observe the placing
sequence and pour rate contained with the plans.
711.6 CURING
Curing shall proceed as soon as the free water has left the bridge deck. On large pours,
the curing may commence before the pouring and finishing operations are completed.
Curing mats shall entirely cover the surface and should be weighted or attached to the
deck forms to prevent dislodging by the wind; mats must be wet at time of placing to
prevent drying by moisture absorption from the deck. These curing mats must be kept
continuously wet by sprinkler or soaker hose for a period of five days, at a minimum, or
until the concrete has attained a 3000 pounds per square inch minimum compressive
strength. In addition to continuous water application, it is sometimes advantageous to
cover the wet mats with a plastic sheeting to slow evaporation. Form removal on bridge
deck vertical faces may not be commenced for 24 hours after completion of the deck
pour, and reinforcing steel protruding through a deck header is to remain undisturbed for
a minimum of 24 hours.
Upon removal of forms and falsework, tie cavities, holes and other defects should be
saturated with water and carefully filled with non-shrink grout.
711.1 WEATHER CONDITIONS
The single most important factor in pouring the deck is the prevailing weather conditions.
Temperature limitations on the deck pour range from a low temperature of 45o F
(ambient) to a high temperature of 90 o F (ambient). Within this range of temperatures,
the reinforcing steel, forms and abutting concrete must also be monitored to maintain a
temperature ranging from a minimum of 35 o F to a maximum of 90o F.
In hot weather, work and pouring schedules must be revised to maintain pouring
temperatures below 90 o F. The concrete to be placed in the forms must be less than 90 o F
in temperature when placed. Evaporation cooling of the reinforcing steel by water spray
or wet burlap shading may be employed to maintain lowered temperatures. Retarding
agent admixtures in the concrete may also be used. The use of any admixture will require
approval by the Materials Engineer.
184
Original Date: 1/3/94
Revised Date: 05/27/16
In cold weather, the use of heated enclosures for curing will be required. The use of
these enclosures may be required while pours are in progress on continuous or monolithic
series of spans which must be completed once begun. The use of heated enclosures to
preheat the forms and reinforcing steel will also be allowed as will the use of insulated
forms when approved. The use of heated aggregate and hot water in the preparation of the
concrete will be allowed subject to approval and on site supervision. Heated aggregates
and water may be used when ambient temperatures may fluctuate below 40 o F.
Aggregates may not be heated in excess of 150 o F, and when combined with the mixing
water, the resultant temperature shall not exceed 100 o F when the cement is introduced to
the mixture. The temperature of the concrete when placed will range between 60 o and
90 o F in the forms. Marginal temperatures will require close cooperation between the
Resident Engineer, Materials Engineer and the contractor.
711.7 STRAIGHTEDGED
Upon completion of the deck curing procedure, the surface of the deck should be straight
edged to identify all surface irregularities. Areas of surface variation exceeding ⅛ inch
per 10 feet must be ground to grade using a machine capable of producing a grooved
surface by use of a multiple edged cutting head. Prior to sealing of the deck and
associated surfaces, all joint sealing on the superstructure must be performed - joints must
be cleaned immediately prior to sealing and must be dry at the time of sealing.
712
BARRIER WALL, SIDEWALK AND PARAPET WALLS
When the deck is cured, or prior to the removal of the curing mats, forming will usually
commence for the barrier wall, sidewalk and parapet walls. Sidewalks, when not on the
same grade and cross slope as the deck, will be finished by hand methods as previously
detailed. Pouring and vibrating conditions will be as for the deck with the exception of
specified pour rates not being required. Surface texturing on the sidewalk will be a
broom finish with suitable traction striations. Where sidewalks are cantilevered from the
deck, a check of falsework supports and tattletales should be made during and after the
pour. Elevation control is critical to prevent water puddles on the sidewalk surfaces.
Extra care must be taken to ensure proper drainage of sidewalk where the barrier wall or
parapet wall interrupts cross slope drainage and forms a longitudinal gutter line. A 2 x 4
straight edge and carpenter’s level should be used to check the gutter line for uniform
flow, or puddles may occur. Scupper and drain openings should be set slightly below
grade to ensure maximum flow. The reinforcing steel for the barrier wall and parapet
wall will normally be tied to dowels protruding from the finished deck concrete. As
previously stated, care should be exercised in placing these dowels to ensure proper
placement and alignment of these walls. The driving and turn lane widths should be
established to determine the front face of the barrier wall, and a working line should be
determined from these width measurements.
185
Original Date: 1/3/94
Revised Date: 05/27/16
Reinforcing steel clearance should be checked and the working line adjusted minimally,
if needed, to provide for required width and reinforcing steel clearance. A check of the
clearance of the reinforcing steel at expansion joints should be made. Variation in
horizontal bars should not crowd the required clearance. Forms for the barrier walls and
parapet walls are often preformed and need only be assembled on site. Many of these
forms are epoxy lined and should not be oiled for use. Effective bracing and shoring
measures must be employed to hold the forms to the correct grade and alignment. These
measures will include the use of “dead men” (large weighted blocks), additional bracing
with increased use of the spreaders and kickers and the use of vertical coil ties to anchor
the forms during the pouring sequence. The expansion joints at intervals in these walls
will facilitate sequential pouring. Care must be taken to run the form by the end of each
poured section to maintain a true line (free of alignment kinks) as the work progresses. A
minimum of 1 foot run by should be used.
Inspection of barrier wall and parapet wall forming and pouring sequences should
include:
a) Checks to determine that all forms are solid and will not move during concrete
placing or vibrating. Determination that all anchoring devices for the forms will be
embedded in the finished product and not pulled through or left closer than 1 inch to
the surface. All spreaders have been removed as the pouring sequence has proceeded
and that the forms on top are parallel, straight and plumb. Correct alignment and
proper lengths between expansion joints should be checked and maintained, as
should clearance to reinforcing steel at side forms and joints. The 3 inch vertical
nose at the gutter line on the barrier wall and the overall heights dimensions should
be checked and maintained. Bolt spacing for bridge rail, handrail or fence should be
checked on the parapet walls.
Concrete should be poured in lifts and vibrated only as required to consolidate the
mixture. Over vibrations will float the forms and drive the entrained air to the form line
where it will be captured against the form and produce a pitted surface on the wall. The
edges of the parapet wall and the perimeter of the expansion joint on the parapet and
barrier walls should be beveled by using a cant strip, while the top of the barrier wall
should be formed to a smooth radius using the ¾ inch radius tool on the sidewalk side of
the barrier wall and a 2 inch radius tool on the roadway face.
In addition, barrier curb may be poured by slip form methods when approved by the
Bridge Engineer. When using slip form methods, additional reinforcing steel is required
to brace the original steel and prevent it from leaning over during the pour. The slump of
the concrete must also be carefully monitored and kept as dry as possible so as to
maintain the desired shape of the barrier curb. The contractor will be required to rub both
sides of the barrier curb while the concrete is still in plastic state and a light brush finish
should be applied. Joints in the barrier curb shall be sawed taking care not to scar the
surface of the deck. The joints will then be sealed with silicone approved by the Bridge
Engineer.
186
Original Date: 1/3/94
Revised Date: 05/27/16
The curing of the sidewalk, barrier wall and parapet wall will be accomplished with wet
burlap, cotton or jute mats in a manner similar to deck curing procedure. The major
difference in requirements is a curing period of 72 hours under continuously wet
conditions and a 24 hour drying period in which the mates will remain in place but will
not be watered.
712.1 RUBBING
Prior to the curing process, the surface of the barrier wall and the surface of the parapet
wall will be sealed by a process called rubbing. This process uses a sand-cement grout to
fill the air voids in the wall surfaces. A proper application will involve grinding all fins
or projections from the wall surfaces, filling all large air voids and holes with a sandcement mixture, applying a sponge coating of sand-cement slurring and, finally, rubbing
a hand applied coating of dry sand-cement as a drying agent into the moist surface with a
burlap cloth. This method should yield a smooth, evenly textured, uniformly colored
surface on the barrier and parapet walls. The contractor also has the option to pull the
forms and rub the concrete while it is still plastic. This is the most desirable method to
obtain a quality surface finish. Typically the contractor will pull the front face form and
rub the front and top face of the wall while leaving the back form in place.
712.2 PLAQUE
A cast bronze plaque is often included in the end wall of St. Louis County bridges. The
plaque is furnished by the contractor to match specifications in the Bridge plans. A
rubbing of the proposed plaque is submitted for approval before the casting in made. As
the plaque is flush mounted in the end wall, a method of securing the plaque during the
wall pour must be devised. Usually, the mounting studs on the plaque may be secured
with tie wire to the reinforcing steel in the wall. Additional reinforcing steel may be
required to obtain a rigid mounting, and the face of the plaque should be covered with a
duct tape or plastic layer to prevent mortar from sticking to the surface. On the recently
poured decks, the plaque is centered in the roadway face of the first section of barrier
wall, right of centerline as you advance by station number across the deck.
Bridge numbers will be painted on the bridge, usually on the end walls, as traffic
proceeds onto the bridge unless the stated bridge plaques are placed.
713
SEALING
A Job Special Provision will be included in the contract to identify the type of sealer to
be used on the bridge deck, barrier wall and sidewalk areas. In general, it will specify the
physical and chemical requirements for the sealer as well as the submittal process needed
for approval. The contractor shall follow the manufactures guidelines for the surface
preparation and application of the material. When a sample is required for approval it
187
Original Date: 1/3/94
Revised Date: 05/27/16
needs to be submitted far enough in advance to allow for the Materials Lab to perform the
necessary testing.
714
DAMPPROOFING
Damp proofing is the application of a bitumen product on the surface of a substructural
unit with the intent to stop the migration of moisture into or through the concrete or joint
below the ground line. The use of damp proofing has largely been supplanted by waterstop and epoxy or plastic spray-on agents; however, damp proofing has limited use on
large retaining walls, foundation systems and railroad bridges.
715
BACKFILLING
Backfilling on any structure should not be done in such a manner as to create uneven
pressure on the abutment or walls. To prevent this condition, backfilling should be done
in even lifts on each side of the wall or abutment and wedging action should be avoided.
Backfilling operations on all structures should be governed by the required compressive
strength tables in the Standard Specifications. Backfill material shall not be placed
higher behind an end bent or center bent than in front until the superstructure is in place.
The material used for backfilling of structures will be of three types:
a) Existing material – from on site or a borrow areas should be clean, free of large or
frozen material, free of wood or extraneous material.
b) Porous Backfill – clean, stone backfill of a designated gradation placed to reduce
hydrostatic pressure in conjunction with weep holes und underdrains.
c) Selected Backfill – compactable graded stone placed to provide a sound area for
other construction (roadway, etc.).
716
APPROACH SLAB
The thickness of the approach slab may be variable, depending on the configuration of
the paving haunch at the abutment. The minimum thickness will be 12 inches.
The reinforcing steel for use in the approach slab will be shown on the plans, and shall
be epoxy coated. Edge clearance for reinforcing steel shall be 6 inches, with end
clearance at the paving haunch being 8 inches and at the roadway end being 9 inches.
Top and bottom clearance will be 2 inches. Reinforcing steel for cast in place barrier
wall section and transitions should also be set in place and tied to the approach slab
reinforcing steel where possible for increased rigidity. Forms and approach slab paving
should be full depth and well braced and should rest on the compacted stone base.
188
Original Date: 1/3/94
Revised Date: 05/27/16
Normally, 4 inches of Type 5 Aggregate base compacted to standard maximum density
will be placed under the approach slab. In order to establish the best riding comfort, a
string line should be used in combination with the survey grade stakes when setting
paving forms. The string line should be held back a minimum of 20 feet on the bridge
deck and extended throughout the approach slab grades and into the roadway pavement
grades beyond. Adjustments to the grade line should be made to remove any breaks in
grade or sharp peaks in vertical curves approaching the structure. Care should be taken to
check both gutter lines at barrier walls for drainage off the approach slab and needed
adjustments made during forming. Because of the isolated nature of approach slab pours,
hand pouring methods are often employed. A check with your Regional Project Engineer
Supervisor should be made for approval if the hand pour, vibratory screed or modified
finishing machine methods are to be used. Surface texture and curing methods for
approach slabs will be the same as for main line pavement, and concrete requirements
will be specified as Pavement or Class B-1. Review of the Construction Plans will reveal
joint requirements associated with approach slab construction.
716.1 MUDJACKING HOLES
The use of mudjack holes in the bridge approach slabs is being phased out. If required
the following inspection will apply.
In addition to reinforcing steel and joint devices, mudjacking holes must also be
incorporated into the approach slab. In order to produce these holes through the slab, a
cylindrical form, usually composed of wax impregnated paper, is used. Probably the
simplest forming procedure is to place the paper cylinder within the form, fill with sand
and anchor with a #4 or #5 reinforcing steel rod driven into the subgrade to or below
pavement surface grade. The mudjack holes are to be set in a grid which will allow for
uniform lifting pressure should mudjacking of the slab become necessary. Refer to
approach slab details for location of holes. Holes are to be 2-1/2 inches in diameter and
must not be constricted or plugged with concrete or mortar when positioned and the slab
is poured. Capping the tops of the cylindrical form with duct tape will facilitate finishing
operations and opening of the holes after the pour. The reinforcing steel rods should be
removed and, before final acceptance, the sand should be inspected for any settlement
under the slab. Should any voids be located, a 4 to 1 soil-cement mixture should be
pumped under the slab to fill the voids without raising the slab. The filled mudjack hole
should be capped with a 1 inch plug of joint sealing material before opening to traffic.
716.2 BARRIER WALL TRANSITION SECTION
Barrier transitions are normally reinforced cast-in-place concrete; however, when allowed
by the Job Special Provisions, precast concrete sections may be used. When used,
precast sections will be anchored in place by 1 inch steel dowels set on 5 foot centers.
189
Original Date: 1/3/94
Revised Date: 05/27/16
Cast-in-place barrier transitions will be poured using B-1 concrete as shown on the
Construction Plans. Reinforcing steel will be epoxy coated, and proper positioning and
clearance will be critical.
Minimum clearance will be 1-1/2 inches, and due to configuration, the reinforcing steel
must be closely monitored. The reinforcing steel in the barrier transition will vary in
height to match the slope of the barrier and will extend 10 feet from the end of the normal
section. Forming, curing and surface texturing procedures will be in accordance with the
previously discussed bridge construction methods. A ¼ inch thick grey sponge rubber
joint filler will be placed at the joint between the end of the bridge and approach slab.
Water stop or silicone sealant will be specified in the Construction Plans.
Also related to the barrier transition is the sidewalk grade and cross slope transition
which must be commonly made in the area of the approach slab end of bridge. As each
structure is different in grade conditions and design, no one set procedure will govern all
problems. The most common problem occurs when the bridge has a continuous cross
slope from centerline to the outside edge of sidewalk and a standard barrier transition is
made on the approach slab. When this occurs, a reversal in cross slope from the standard
sidewalk configuration of 2 percent toward the gutter line to 1½ percent away from the
gutter line must be made to match the bridge sidewalk configuration. This reversal in
cross slopes is best accomplished by transitioning from 1½ percent cross slope toward the
gutter line in the next 20 feet of sidewalk. A 6 inch rise in the sidewalk grade must be
made in the 13 feet 6 inch barrier transition area in order to transition from bridge end
sidewalk elevation to top of curb elevation at the end of the barrier.
717
PEDESTRIAN FENCE OR ALUMINUM HANDRAIL
On almost all bridges and culverts, a pedestrian fence, bridge guardrail or aluminum
handrail system will be employed for pedestrian safety either at the edge of deck or
mounted to the parapet wall. The method of attachment of these three systems will
usually involve anchor bolts poured in place in the deck or on the parapet wall. The
anchor bolt will be of two types: The first is “L” shaped with the long leg threaded; the
second is formed of two “U” shaped bolts jointed by two #4 reinforcing bars tack welded
in the corners of the parallel U-bolts to form a solid unit. The upper portions of the Ubolts are to be threaded. In both cases, the anchor bolts are to be hot dipped galvanized.
All anchor bolts should be set using a template to provide exact placement and support.
When placing the template, accurate location, even spacing and lateral clearance will all
require inspection. The spacing of anchor bolts should always be shown on the plans and
should be accurately reproduced to prevent error as fabricated sections allow minimal
tolerances (+1/4 inch). Usually, spacing for fence posts will have a maximum distance of
10 feet, while guardrail stanchion spacing will match standard guardrail lengths (6 feet 3
inches). The template should be centered by use of a longitudinal string line with spacing
transversely marked on the side form which will also support the template. A minimum
lateral clearance of 6 inches is usually imposed from the outside edge of the form line
from the ends of wingwalls or expansion joints.
190
Original Date: 1/3/94
Revised Date: 05/27/16
When the anchor bolts are to be laid out on the curve, the plan should contain a drawing
indicating offsets from a tangent working line or uniform radius from an accessible radius
point.
The minimum stick through distance for the threaded bolt end should also be checked and
normally will be a minimum of 2 inches. Each anchor bolt set should also be checked for
plumb and for spacing of the individual threaded ends within the set. A check of
diagonal distances between opposing bolts will provide the quickest indication. During
the concrete pour, care should be taken to prevent dislodging or misaligning the anchor
bolts. Vibration should be closely check as over-vibration will tend to misalign the
anchor bolts, while under-vibration will produce poor consolidation of the concrete
around the anchor bolt and an uneven surface for the base plate to rest upon.
Following completion of the concrete pour, the anchor bolts should be rechecked on all
points and the template removed to that the area of the base plate can be brought to grade
and leveled to a true plane. The area of the base plate may be ground or rubbed to attain
the desired dressed surface.
Unless otherwise approved by the Bridge Engineer, drilled in place, expansion anchor or
chemical anchor bolts may not be substituted for poured in place anchor bolts. Base
plates for pedestrian fence on structures shall be set on a bed of a non-shrink aluminum
oxide mortar, a minimum of ½ inch thick when galvanized steel posts are used, or a 1/8
inch thick insulated pad when aluminum posts are allowed. Correction in plumb and
alignment are to be made in mortar bed or by grinding. The posts are welded to the base
plat and, in final position, must be plumb and in proper alignment. Post sizes will vary,
but, normally, end or terminal posts will be 2-1/2 inches in diameter while line or pull
posts will be 2 inches in diameter. At a minimum, a continuous top rail must be run from
terminal post to terminal post and must be fitted with self-centering couplings and a slip
joint coupling every fifth coupling. When this is done, a tension wire must be run at the
bottom of the fence fabric for the entire length. More often, a top and bottom rail will be
required between all posts in each panel. Post to rail connection are to be welded with
expansion fittings in the top and bottom rail between posts, and vent holes are to be
provided at all internally closed joints for the zinc coating or aluminum coating process.
Normally, rail sized will be from 1-1/2 to 2 inches in diameter. A longitudinal brace is to
be used in each panel adjacent to terminal post and will be the same diameter as the rail.
The brace will be located at mid-height on the fence panel and will be supported by a
diagonal ½ inch truss rod. When overhead caging is a part of the fencing on the
structure, it will be connected to the vertical fence posts by pipe dowels sized to provide a
close tolerance fit. Pull posts will be spaced at intervals of not more than 100 feet and
may require braces and truss rods in accordance with fence fabric height.
The fabric to be used for chain link fence will be formed of helically wound and
interwoven wire shaped to produce squats 2 inches on a side. The fabric height will be
191
Original Date: 1/3/94
Revised Date: 05/27/16
measured as an overall dimension from end of barb or knuckle to opposite end of barb or
knuckle (+1 inch) for unstretched fabric. Usually a minimum height of 6 feet will be
required for pedestrian fence on a structure. The fence fabric will be composed of either
zinc coated, aluminum coated or vinyl coated steel wire or an aluminum alloy wire. The
type of fence fabric will also determine the type of post, rail and bracing to be used.
When zinc coated or aluminum coated steel fabric is used, the appurtenances must be
zinc coated. Aluminum alloy fabric will require aluminum alloy appurtenances, and vinyl
coated fabric coated will require either zinc coated or aluminum alloy appurtenances.
Wire ties will also match the type of fence fabric, with zinc coated, aluminum coated or
aluminum alloy being required for zinc or aluminum alloy fabric, aluminum alloy wire
ties being required for aluminum alloy fabric and vinyl coated wire ties being required for
vinyl coated fabric. Fabric wire ties should be placed at such spacing as to adequately
hold the fabric to the posts and rails (about 3 foot centers) after it is stretched in place.
Tension wire will be zinc coated or aluminum coated for all application except when
vinyl coated fabric is present; then a zinc coated vinyl covered wire must be used. The
gauge of the fence fabric will generally be specified on the plans; normally, 36 to 42 inch
high fence will be 11 gauge wire, 48 to 60 inch high fence will be 9 gauge wire and 72 to
84 inch fence will be 6 gauge wire. A notable exception will be on pedestrian bridges
with overhead caging where gauge will be smaller to allow for bending of the fabric to
match the framework and placing of any joints at the top of the caging. Careful
inspection should be made to ensure that the contractor furnishes the correct gauge fabric.
A measuring tool is available at the Materials Laboratory to check on the size of the
fabric.
Base plates for guardrail stanchions will bear on a smooth level surface obtained by
grinding or rubbing if necessary. The stanchions will be aligned by using shims with a
maximum deviation from plumb or true alignment of 3/8 inch. Base plates may mount
directly to the deck or may mount on the side of the deck through the flange of the
stanchion. In either case, exact spacing and configuration will be critical and must be
closely monitored. A standard guardrail section is affixed to the stanchions 21 inches
from center or rail to top of deck. An end section at the terminus of the rail end or
terminal section will extend beyond the bridge or culvert. A top handrail is attached to
the top of the stanchions to complete the bridge rail. This construction method is being
phased out in lieu of the barrier wall but has limited application on existing bridge
maintenance and improvement projects. Cast aluminum rail posts will be mounted to the
parapet wall for the tube type aluminum rail in a manner similar to that described for base
plates. The concrete surface must be a true plane obtained by grinding or rubbing as
necessary; however, the base of the aluminum rail post must be insulated from the
concrete by using a 1/8 inch bearing pad or a coating of caulking compound which is
aluminum impregnated with the consistency of putty. The rail posts will be loosely
attached to the anchor bolts until the tube rail is mounted to the posts for its entire length.
The rail will then be aligned and the nuts on the anchor bolt tightened. If necessary,
aluminum shims may be used to align the posts so that no sharp breaks in grade or
alignment exist in the rail in final position. A tolerance of 1/8 inch from true alignment
will be allowed.
192
Original Date: 1/3/94
Revised Date: 05/27/16
Material used in the fabrication of the aluminum rail or posts will normally be field
inspected before placing. Inspection will include checking for lamination, cracks,
discoloration, marring or scoring of the exposed surfaces. Objectionable appearance will
be considered a cause for rejection. Testing will also include X-rays of the rail and posts
and chemical analysis of the aluminum material which will be transmitted with the
certifications.
718
WATERPROOFING
Waterproofing is used to cover concrete railroad bridge decks which support a ballast
track. Because of this limited application, waterproofing is not often included in
contracts. When required, waterproofing is to be applied only when the ambient
temperature is above 50o F and the weather is not humid. The concrete surface is to be
dry and clean when the asphalt material is placed as a primer and should contain no
projections or fins or surface depressions. The preliminary application will be as required
for ordinary dampproofing, i.e. primer coat at one gallon per 100 square feet and a mop
coat at 50 pounds per 100 square feet. Deflection and expansion joints are to be covered
with impervious paper 36 inches wide and centered on the joint before the waterproofing
primer material is applied. Strips of cotton fabric will be laid on the mop coat while still
hot and pressed into place. Successive layers of cotton fabric will be applied to the mop
coats as required. Normally, 2 layers of asphalt treated cotton fabric with 3 mop coats of
asphalt will be applied; however, an additional layer of cotton fabric and an additional
mop coat of asphalt may be required by the Special Provisions. Successive layers and
mopping’s will completely cover and seal the preceding layer. Asphalt for the mop coat
will be placed at a rate of 4-1/2 gallons per 100 square feet and shall not be heated over
350o F. When placing two layers of cotton fabric, the bottom layer will be laid so as to
offset the top layer by one half the width plus 2 inches. The fabric will be laid in shingle
fashion, with 2 inch joint overlaps and a 12 inch wide end lap. For three layers of cotton
fabric, the procedure will be the same except the initial offset will be 1/3 of the width
with a minimum overlap of 2 inches. The waterproofing will be extended into drainage
opening and will be sealed on the sides, ends, structural members and at all terminus
points. Asphalt planking will be placed as soon as possible. Prior to placing planking, a
hot asphalt coating of not less than 50 pounds per 100 square feet will be applied. Planks
will be laid tightly together with edges and ends coated with asphalt material prior to
placing so as to fill all joints with hot asphalt.
719
TIMBER CONSTRUCTION
Another once common construction procedure which is being phased out is timber
construction of structures. Limited applications for temporary use on detours or shoofly
routings may still be provided for in the contract Special Provisions as may maintenance
provisions for existing structures; however, retaining walls will be the major component
of this type of construction for roadway application. When temporary structures are to be
built in conjunction with the project construction, detailing and erections sheets will be
193
Original Date: 1/3/94
Revised Date: 05/27/16
included in the plans. In general, all timber, whether treated or untreated, will be stored
on the project site in such a manner as to prevent warping and to shed water. Treated
timber will be handled with rope or fabric slings and in such a way as to avoid damage to
the treated external surface. Damaged areas will be painted with two applications of the
appropriate wood preservative, either creosote or pentachlorophenol. Timbers are to be
set and secured as specified in the plans with minimum (+1/4 inch) tolerances followed.
Shims are not to be used with the exception of the backing planks at the end bents. These
planks may be shimmed to obtain a pane surface on the exposed sides due to
irregularities on the piling shape. Transverse floor planks on the deck are to be laid to
produce a straight outer line of the bridge from end to end. Floor planks should be laid
heart side down to prevent cupping and should be secured at each joist with a minimum
of two steel spikes of the proper length. Untreated floor planks should be laid with full
edge contact. Longitudinal deck planks and bumper guards should have staggered joints
when laid. Sway bracing, when required, should be secured at each member and should
be used to align bent members before the cap is set.
In general, nail and spike length should be approximately twice the thickness of the
member being fastened. Bored holes for round drift pins, dowels or spikes should have a
diameter of 1/16 inch less than the fastener used.
Bored holes for square drift pins or dowels should have a diameter equal to the side
dimension of the fastener, while holes for machine bolts and rods should be 1/16 inch
greater in diameter than the bolt or rod diameter. Bored holes for lag screws should have
a diameter not larger than the body of the screw at the base of thread. Bolts with counter
sunk head will require a cut washer and a bored hole not larger than the washer at the
counter sunk end only. O.G. washers shall be used under nuts and all bolts and under
heads of all bolts except counter sunk bolts. All nuts will be securely tightened. Nail
heads should be driven flush without bruising the wood.
719.1 TIMBER RETAINING WALLS
Wooden tie beam retaining walls are built of treated wood normally 8 inches x 6 inches x
8 feet in length. The beams are treated with creosote or pentachlorophenol. Any surface
damage will be treated with two painted applications of the appropriate preservative.
Beams must be straight, free from warping, major defects and large knotholes, and should
be rough sawn with neat edges. Spikes will be galvanized steel of a standard commercial
grade, a minimum of ten inches in length and 3/8 inch in diameter. The foundation area
of the wall cells will be excavated a minimum of 10 feet wide measured from the front
face of wall. The initial row of stretchers will be set full depth below the existing ground
line or proposed finished ground line on a firmly compacted, level base. This beam
should be set true to line and inclined on the front face to produce a 1-1/2 inch camber.
This camber will produce the required batter on the wall. Successive rows of stretchers
will be placed with a 1 inch set back per row, and stretchers must be necessary to produce
staggered vertical joints. Both inside and outside corners will be formed by overlapping
the stretchers in successive rows; ends will be stepped to match the existing ground line
194
Original Date: 1/3/94
Revised Date: 05/27/16
or to produce a 3 to 1 slope. Each stretcher should be secured to the previous member by
a minimum of four spikes per tie beam. The spikes should be driven at an angle, full
length, into both tie beams, and the heads should be set flush.
Deadman anchors will be installed commencing with the first row of stretchers above the
finished ground line. These anchors will be constructed by placing a header beam at 90
degrees to the stretchers and nailing a three foot long anchor section at the beam and
above and below the header. A minimum of two spikes will be required to secure the
anchor beam to the header and two spikes to secure the header to the stretcher. The
header should also have the required 1 inch setback at the wall front face. The anchors
will be spaced along the wall at stated intervals (normally 8 feet). No less than 2 rows of
deadman anchors per wall tier will be allowed. For single walls, a maximum tier height
of 6 feet will be allowed with deadman anchors set at every third or fourth stretcher row,
or closer, with the last anchor being set the row below the top of wall stretcher with no
over beam anchor present. A maximum slope of 3 to 1 may be anchored by this single
tier arrangement. Where multiple stepped tiers are required for walls in excess of 6 feet
in height, the tier height will be limited to 4 feet with a maximum offset distance between
tiers of 4 feet. The deadman anchor arrangement will be as previously outlined, with the
first offset tier stretcher resting on and secured to the top header of the lower tier. A
maximum 3 to 1 slope may be allowed above the tier. Backfilling will be composed of
placing a continuous run of 2 inch clean stone, two feet wide, behind the front face of the
wall, with or without weep holes, and granular, select or dirt backfill for the remainder of
the tier. A minimum of 90 percent of standard maximum density will be require for
compaction of the backfill, and where multiple tiers are constructed, a 1 percent slope
between tiers will be required.
720
CRIB RETAINING WALLS
Also built as retaining wall structures, the concrete or metal bin crib or cell walls are
used. These walls are composed of interlocking reinforced concrete or metal bin units
which form either open or closed face cells which are backfilled to form a gravity wall.
Concrete units are composed of precast, reinforced concrete and will be symmetrical
about their principal axis. These units will be dense, sound and free from cracks, spalls
and surface imperfections. The wall will be placed on a firm foundation in compacted or
original ground. The bottom row of stretchers will be laid on line and at the elevation
shown on the plans. Stretchers will be laid ¼ inch from the projecting lugs on the
headers, and a single layer of 55 pound roofer’s felt will be placed between bearing
surfaces. Stretchers and headers will be laid level and to the elevation shown on the
plans. Backfilling will proceed as the individual cells are built. The backfill must be
maintained within 3 feet of the ongoing construction or the placing operation will be
halted. Backfill outside of the cells will not be placed higher than inside the cells. The
individual cells will be backfilled with compacted impervious material to height of 6
inches above the finished ground line. The impervious backfill will be so graded as tot
drain from back to front of the cells. Closed face crib units will be backfilled to the top
grade with a coarse aggregate, a paving stone, compacted as required. Open face crib
195
Original Date: 1/3/94
Revised Date: 05/27/16
units will be backfilled to the grade with quarry run stone or 1 man (50 pound) stone with
a minus filler for the voids. Hand placed stones will be set to block the openings between
stretchers as the remaining backfill is placed.
Metal bin walls will be constructed using galvanized metal bins and columns. The
foundation for the bins will require the excavation of a narrow trench just slightly wider
than the bins and columns and a minimum of 18 inches below finished grade. The
columns must be firmly bedded on compacted material and mounted on a base plate in
full contact with the subgrade. The stretchers will be set to line and grade and with the
proper slope commencing in the trench and proceeding upward. The stretchers will be
erected and secured to the columns to form cells of the dimension and height shown on
the plans. Backfilling will follow the procedure as stated for closed face crib walls.
721
STRUCTURAL PLATE BRIDGE AND CULVERT CONSTRUCTION
Another method of small bridge and culvert construction or replacement which is
becoming common is the use of structural plate pipe, structural plate pip-arch culvert,
structurally reinforced structural plate arch and structurally reinforced structural pipearch. This related group of structures is easy to construct, requires smaller foundations,
provides standard load bearing capacities and may be used with shallow cover for the
roadway fill. Each member of this group is composed of curved sections of galvanized
corrugated metal plate which are field erected to form the shaped structure as required.
721.1 STRUCTURAL PLATE PIPE AND PIPE ARCH CULVERT
Structural plate pipe and pipe-arch culvert shall be laid on a uniformly compacted and
properly shaped subgrade. Properly shaped will mean that 10 percent of the subgrade
vertically will be graded so as to match the bottom surface of the structure’s floor plate.
Excavation will be made to the elevation shown on the plans unless rock or soft areas are
encountered. When rock is encountered, it will be removed to a depth of 8 inches below
grade and backfilled and shaped with a suitable compactable material. Soft areas will be
removed and backfilled with granular material as per standard practice. If shown on the
plans or elected by the contractor, a 2 inch layer of sand may be used to bed and properly
shape the subgrade for the structure. A uniformly compacted, supportive subgrade,
properly shaped must be in place before assembly of the structure begins.
The structure must be laid true to line and grade. Settlement will be reason for relaying
the structure at the contractor’s expense. If so required be the plans, the structure may be
laid with camber placed initially in anticipation of settlement. Smaller structures of this
type may be assembled outside the trench and set in place by cranes, or the plates may be
assembled in place. Erection drawings will be provided by the supplier and should show
the dimensions of the plates, plate numbers and sequence of erection. Care must be taken
to avoid damage to the smelter coating on the plates. Scratches may be repaired by two
applications of zinc dust-zinc oxide or zinc rich pigmented paint. The zinc alloy stick
method, which is a field hot galvanization process, will be required for large areas of
196
Original Date: 1/3/94
Revised Date: 05/27/16
smelter damage. Areas which have be stretched, dented or punctured may result in
rejection of the plate. All bolts, nuts and washers will be torqued to the foot-pounds
required by the plans or erection drawings. Backfilling will be performed using either
stone or dirt for fill material. When dirt is used for backfill, it will be free from large
clods or boulders. The material will be placed in 6 inch lifts and compacted to the same
density as the roadway material. The backfill will be placed in successive level layers on
each side of the structure until the top of the structure is reached. Where necessary, or
with shop elongated pipe, supportive struts may be necessary to support the structure or
prevent plate distortion during backfilling. When rock or stone backfill is used, a
cushioning layer of fine rock mixed with dirt must be placed before the larger stone or
rock material is placed. The cushioning layer must be placed and compacted as the rock
fill is added to as to always protect the coating on the structure.
721.2 STRUCTURALLY REINFORCED PLATE ARCH AND PIPE ARCH
Structurally reinforced structural plate arch and pipe arch will be constructed in a manner
similar to that previously stated. Notable differences include:
a) Bottom or floor plates are not always used with these structures. Footings are often
constructed to support the sides of the arch with no floor or a paved concrete floor
present under the structure. Footings are reinforced concrete keyed into rock with a
load transfer device embedded or connected by anchor bolts at grade on the top of
footing. The load transfer device usually an unequal leg channel into which the side
plates of the structure are bolted.
b) The overall span of the arch is greater and requires more precise erection
procedures. Detailed erection plans will be provided by the supplier as will a method
of alignment and elevation control to be used during erection and backfilling.
Typical alignment and elevation control will be monitored by using a steel fabricated
loop welded to a standard ¾ inch nut. The loop can be mounted to any inside
continuous row of bolts on the side or center of the arch at each plate. By aligning
two or more of these loops, a visual check may be made for alignment, or a string line
may be passed through the loops to obtain a measurable alignment check at each
point. Elevation control is maintained by taking shots for comparison on each loop
at intervals during construction for comparison to a computed grade.
c) A thickness check on smelter coating should be made by Materials Testing
Laboratory personnel using a magnetic gauge before erection begins.
d) Because of the span and geometry of these arches, a set of thrust beams composed of
reinforced concrete must be attached to the plates as shown on the plans. Partial
backfilling is usually required to the bottom of the thrust beams to facilitate forming.
e) Very specific compaction procedures must be followed utilizing a minus granular
backfill with controlled moisture content, regulated lift thickness and stringent testing
197
Original Date: 1/3/94
Revised Date: 05/27/16
requirements. The type of backfill material will be specified in the plans. A proctor
showing the moisture-density relationship and testing procedures for the modified
proctor must be obtained. Compaction will be set at a minimum of 90 percent
maximum density as determined by field testing. Lift thickness will be limited to a
maximum of 8 inches.
721.3 PIPE ARCHES
Structural Steel Plate, Structural Plate Pipe Arch and Reinforced Structural Plate Arches
as specified in the Specifications should be staked for alignment either from a centerline
of structure stake or centerline of footing with offset stake and tacked hub for elevation
control of the footing. Generally, the most important factors in this type of structure are
parallelism of the footings and anchoring system and a constant gradient on the footing.
By far the most important staking in this mode of construction is the strict elevation
control required during the backfilling operation. This strict elevation control is
necessary to prevent distortion of the structure caused by variable backfilling pressures.
Elevation control should be run on the centerline of the structure with a hanger provided
to establish a constant gradient through the structure. By a comparison of elevation
during the backfilling, the structure can be monitored and kept within specified deflection
parameters.
722
PAINTING
Painting of newly constructed structures and maintenance painting of existing structures
will consist of preparation of the surface and the application of one of four systems of
paint coatings.
Surface preparation for newly constructed steel beams or girder bridges will include both
shop and field operations.
When System A or System B painting is to be performed, surface preparation will
include:
a) Abrasive air blasting to produce a nominal height of profile of 1.5 mils.
b) Complete removal of oil, grease, dirt, rust, mill scale and other foreign materials.
Minimal streaks and discolorations will be allowed which are caused by rust stain or
oxides. On pitted surfaces, the rust residue present in the bottom of pits may remain.
c) At least 66 percent of each square inch of surface must be free from all visible
residues and the remaining are limited to the allowable items in (b) above.
When System C painting is to be performed, surface preparation will include:
198
Original Date: 1/3/94
Revised Date: 05/27/16
a) Abrasive air blasting to produce a nominal height of profile of 1.0 mils.
b) Removal of all oil, grease, dirt, rust, mill scale and other foreign materials. Minimal
streaks or discoloration by rust stain or oxides.
c) At least 95 percent of each square inch of surface must be free from all visible
residues and the remaining area limited to the above mentioned streaks or
discoloration.
Immediately following blast cleaning, all abrasives must be removed from all surfaces,
pockets and corners and the first prime coat placed. This initial coating must be in place
no later than 234 hours after the surface preparation is completed. Any surface which
rusts before painting must be recleaned. Contamination of the undercoat is cause for
rejection with a complete recleaning and repainting of the surface being required.
The four systems of painting will consist of the following:
a) System A – A primer coat of red lead paint, an intermediate coat of brown paint and a
finish coat of aluminum paint.
b) System B – A primer coat of basic lead silicon chromate paint, an intermediate coat
of maroon basic lead silicon chromate paint and a finish coat of green or aluminum
basic lead silicon chromate paint.
c) System C – A primer coat of inorganic zinc silicote paint, no intermediate coat and a
final coat of green vinyl paint.
d) System E – A primer and intermediate coat of dampproofing red primer paint and a
finish coat of aluminum paint.
A required thickness of paint coating is specified for each application. Prime coat dry
film thickness for Systems A, B, and E will be a minimum thickness of 2.5 mils. The
intermediate coat dry film thickness for Systems A, B, and E will be a minimum of 1.5
mils and for System C will be a minimum of 3 mils. Regardless of the paint system,
measurements of the dry film thickness must be made on a daily basis to ensure
compliance. A magnetic gauge, available from the Materials Engineer, will be used to
determine paint thickness. Recoating and touchup of thin areas must be made as soon as
possible. System C will require recoating within 24 hours.
Paint for use on the project will be premixed with the exception of two component
aluminum or inorganic zinc paint which will be mixed on site. Paint which has thickened
or hardened in its container will be rejected as will paint which has separated and cannot
be remixed to a good consistency. Thinning of premixed paint will be allowed in
accordance with the manufacturer’s recommendations to produce the proper consistency.
Thinner may be added only when mixing the paint. Thinning agents and amounts will be
199
Original Date: 1/3/94
Revised Date: 05/27/16
specified by the producer and, in general, will be either turpentine or mineral spirits.
Tinting between successive coats of similar paints to indicate coverage of the steel is a
must.
Two categories of painting apply to new structural steel; namely, shop painting and field
painting. Shop painting may only be performed after steel fabrication has been
completed, inspected and approved. Inorganic zinc primer will be applied to all the
following surfaces regardless of the specified paint system:
a) All inaccessible areas after erection.
b) Contact surfaces of high strength and machine bolted connections.
c) All surfaces to be in contact with concrete. All contract surfaces will receive a single
coat of primer with a dry film thickness of not less than 2 mils. Inaccessible surfaces
will receive two coats of primer which will produce a dry film coating thickness of not
less than 5 mils.
When inorganic zinc primers are specified, all surfaces of the structural steel will be
coated. Special attention will be given to painting the contact areas of high strength
bolted connections and the tops of girder and beam flanges which will being contact with
the concrete to ensure a minimum dry film thickness of 1.0 mils and a maximum
thickness of 2.5 mils.
When other paint system primers are specified instead of inorganic zinc, the following
surfaces will be coated:
a) All web and flange surfaces normally coated.
b) The top flange of beams or girders in contact with concrete for a distance of 5 feet
from centerline of bearing of each intermediate bent.
c) Stringer and girder top flange vertical faces.
d) Contact surfaces between bearing and beam flanges.
e) Metal surfaces in contract with or embedded in concrete, excluding anchor straps,
expansion deice bars and anchor bolts.
f) All inaccessible areas will receive a 3 coat application of primer to produce a
minimum 6 mil dry film thickness of the specific paint.
Shear connector studs need not be painted; also, steel surfaces within 2 inches of edges to
be field welded need not be primed.
200
Original Date: 1/3/94
Revised Date: 05/27/16
Field painting will not be performed until the deck has been placed and the form work
removed. Exception will be for touch-up painting and painting inaccessible areas as
erection proceeds. Touch-up painting will be performed at any damaged or rusted area
on the beam or girder, at field connections and field welded areas at areas specifically not
shop painted. Touch-up painting will utilize the same type of paint specified for shop
application. Small cracks and/or cavities will be filled with a red lead paste when System
A or B are used and a waterproof seal has not been obtained by the primer application.
The methods of application of the coating will be the same for shop or field categories.
Application of paint will be by brush, roller, air spray, airless spray or a combination of
methods. Spray application will be performed utilizing equipment operation under
pressure to atomize and place the paint on the steel surface. Pressure regulators and
indicator gauges must be present and working during application. A minimum ½ inch
inside diameter hose must be used to supply paint to nozzle. Spraying equipment must be
kept clean and free from any foreign material which might contaminate the paint,
including solvents used for equipment cleaning. During spraying operations, the paint
must be continuously mixed by agitators either in the spray pot or paint container.
Mechanical agitators using stirring paddles must reach to within 1 inch of full depth in
the spray pot or paint container. All sags or runs will be immediately brushed out as the
paint is applied. All areas inaccessible to the spray equipment will be painted by brush
or, if necessary, painted by daubers or sheepskins. Brush application of paint will be
made by a brush of 5 inches or less in width and of quality which will produce a smooth,
uniform coat of paint. Paint by brush will be worked into corners and crevices, and all
sags or runs will be brushed out. Roller application of paint will be made with a quality
roller in which the nap will produce a smooth, uniform surface. Any sags or runs must be
brushed out immediately. Paint in Systems A and B will be considered to be dry when
rapid rubbing of the ringer on the coating does not produce a break in film. System C
paint will be considered dry based on manufacturer’s recommendations of drying time.
Shop and field painting will also be governed by weather and moisture limitations. All
pain, except inorganic zinc, may not be applied when the air or surface metal temperature
is below 40o F. Inorganic zinc paint may be applied when the temperature exceeds 25o F.
Painting will be discontinued when the surface temperature falls below 25o F. Painting
will be discontinued when the surface temperature of the steel will cause blistering of the
paint. Paint may not be applied to a wet surface or when the steel temperature is below
the dew point. Any paint exposed to moisture or freezing temperatures, except inorganic
zinc, will be considered damaged and, upon drying, will be removed and replaced.
Painting done in an enclosure must remain covered until dry.
Maintenance painting of existing bridges will, in most aspects, differ but little from the
procedures and requirements already enumerated. Surface preparation procedures and
heights of profile for the various paint systems will be exactly as previously cited as will
requirements for surface cleaning. The only addition to these requirements is the
inclusion of chipping hammers, steel brushes and power equipment to augment the
cleaning process. Commercial blasts and spot blasts are often called for on repainting
projects; these names are misnomers for a 95 percent clean, 1 mil. removal similar to the
201
Original Date: 1/3/94
Revised Date: 05/27/16
surface preparation for System C painting. The same requirements for the various
systems of paint, dry film thickness for each system, paint thinning, paint tinting, weather
limitations and methods of application will all apply equally for new or maintenance
painting.
The major area of difference between new and maintenance painting will be in the actual
project management. Because abrasive air blasting and the actual painting will require
road closures, lane restrictions or detours, proper notification of all emergency agencies
(police, fire, ambulance, etc.) and other governmental bodies will be required, possibly
on a daily basis. Where navigable rivers are crossed, the Coast Guard and any water
works pumping plants should also be notified and applicable permits obtained by the
contractor. Where required, a permit from the Environmental Protection Agency (EPA)
or Missouri Clean Water Commission must also be obtained.
Before the actual surface preparation begins, the veering devices and structural integrity
of the bridge should be checked. This procedure should be repeated following abrasive
air blasting and after final cleanup. Frozen bearing devices, cracked superstructure or
substructure, bent or damaged structural members or heavily rusted or eroded areas on
the structure should be brought to the attention of your Regional Project Engineer
Supervisor and the Bridge Engineer. Caulking of seams and joints should be performed
as painting progresses. When work has commenced, the weather conditions will be of
primary importance. Factors which will affect the paint, such as surface moisture, dew
point, ambient temperature and humidity must be closely monitored. Also wind direction
and velocity will be critically when paint overspray might contaminate the water below
the bridge or coat private property adjacent to the project. Several ribbons mounted at
various elevations should be used to monitor wind direction and velocity and may forma
basis for halting all or portions of the work. Clean up of the project will also be
important from an environmental viewpoint. No solvents or thinning agents should be
left or dumped at the bridge site.
CHECK LIST – DECK POURS
723
FALSEWORK AND FORMS
a) Do we have falsework drawings?
b) Did the contractor follow these drawings?
c) Has splicing and blocking been kept to a minimum?
d) Is the falsework on sound footing?
e) Was acceptable form lumber used?
f) Will form ties break behind concrete surface?
202
Original Date: 1/3/94
Revised Date: 05/27/16
g) Are all forms nailed down?
h) Do the forms fit tight?
i) Was a mill cut molding used for bevels?
j) Have the forms been oiled?
k) Is there an excess of oil on forms?
l) Is a method of checking settlement provided?
m) Has line and grade of forms been checked?
n) Are all jacks tight and secured?
o) Read Specifications for all material and equipment requirements.
p) Have headers been checked for line and grade?
q) Has the header been provided with a key?
r) Area the end forms and ones for attaching temporary timber header in place?
s) Is the method of bracing forms of overhang satisfactory and has the grade been checked?
t) What is the sequence of falsework removal?
u) Is housing provided if heating is necessary?
REINFORCING STEEL
a) Is reinforcing steel free of oil, rust, etc?
b) Is all reinforcing steel in place?
c) Has all epoxy damage been repaired?
d) Has it been checked against the bar bill and drawings?
e) Are bar chair supports of proper size and spaced correctly?
f) Was it checked for proper location?
203
Original Date: 1/3/94
Revised Date: 05/27/16
g) Has it been properly tied?
h) Has the steel actually been measured by the inspector for locations – horizontally and
vertically?
i) Be sure all steel is tied – Do not stick any reinforcing.
CONCRETE
a) Where is it to be obtained?
b) Has batching equipment been checked?
c) Have truck mixers been checked?
d) How many yards are in the pour?
e) Does the contractor have sufficient quantities of inspected air-entrained agent, cement,
sand stone and water?
f) Has moisture test been run?
g) Who is the plant inspector?
h) Has he read the specifications on this phase of the work?
i) Is plant inspector familiar with the plant?
FINISHING
a) How is the concrete to be placed?
(1) Is the method satisfactory?
(2) Has the contractor provided assurance that he can obtain specified rate of
placement?
(3) Has he demonstrated this season the ability to maintain the rate of placement?
(4) Who is the inspector that will make the cylinders, slump and air tests?
(5) Does he know how to do these tasks?
b) Are the screed rails located out of the concrete?
204
Original Date: 1/3/94
Revised Date: 05/27/16
(1) Are they located to permit finishing the entire width of the pour?
(2) Are they sturdy enough to hold the finishing machine?
(3) Are they straight?
(4) Has the grade of the rail been checked by the inspector?
(5) Are the screed rail supports satisfactory (adjustable)?
c) Will the finishing machine move freely on the screed rails?
(1) Has it been checked for the proper cross-section and grade?
(2) Will it strike off the concrete uniformly?
(3) Will it work up sufficient grout over the entire length to permit finishing?
(4) Do we have sufficient and proper vibrators on hand for placing?
(5) Do we have a supervisor for this phase of the work?
d) Miscellaneous Equipment
(1) Do we have enough good bridges?
(2) Do we have enough straightedges?
(3) Do we have a texturing device?
(4) Do we have the proper edging tools?
(5) Do we have a competent finisher?
(6) Are the mats on the job?
(7) Are they wet and ready for use?
(8) Do we have a tank to soak the mates prior to placing?
(9) Are soaker hoses or sprinklers available to keep the mats continuously wet?
(10) Will the contractor’s superintendent be on the job during the pour?
(11) Is there burlap on the job for emergency use (rain, delay for finishing, etc.)?
205
Original Date: 1/3/94
Revised Date: 05/27/16
DURING THE POUR
a) Is concrete of proper consistency?
b) Run air tests and slump tests on first batch and at frequent intervals thereafter.
c) Is all equipment functioning properly?
d) Make several passes with finishing machine. Use until there is no appearance of
irregularity in the slab surface.
e) Check straightedge operations to ensure good riding surface.
f) Checking surface with straightedge should be the last operation on the concrete surface
before texturing.
g) Check forms for settlement.
h) Check screed rail grades after forms are loaded.
i) Check finished concrete for time to texture, cure, etc.
j) Make the necessary cylinders.
206
Original Date: 1/3/94
Revised Date: 05/27/16
SECTION 800
ROADSIDE DEVELOPMENT
801 PLANTING TREES, SHRUBS AND OTHER PLANTS
801.1 GENERAL
On the majority of road construction projects, as a part of the roadway restoration, a tree planting
program is available to the affected property owners. All projects with the exception of the
infrastructure improvement projects, asphaltic overlay projects and the concrete replacement
projects will be included in this program. Selected existing trees damaged or removed to
facilitate construction will also be included on these projects.
This is a separate contract and has nothing to do with the roadway contract. Depending on the
window available, tree planting can be accomplished after the contractor has completed his final
restoration so there will be no damage to the newly planted trees. Planting can also be
accomplished the fall after the project has been completed and closed out.
The initial contact with the property owners adjacent to the project will be made by the Resident
Engineer. The minimum number of trees for each property is 2 with the maximum number of
trees determined as 1 tree per every 50 feet of roadway frontage.
An agreement for the number of trees and/or shrubs to be planted, a self-addressed stamped
envelope, a list of trees and shrubs available for planting and a permit for egress to the property
will be provided to each affected property owner. The packet can be obtained from your
Regional Project Engineer Supervisor. (Note: The stock of available trees for planting changes
from season to season; an updated list will be provided to show current selections.) The property
owner may select plantings from this list and specify his selection on the agreement which
should be returned to the main office within 10 days, if possible. A copy of this agreement
should be maintained in the Project Files.
802 PLANTING REQUIREMENTS
Tress will generally be planted in the fall, winter or early spring with evergreen shrubs and
conifers being planted throughout the year. All trees and shrubs have a 1 year nursery
replacement guarantee. Normally, trees will not be planted on the right-of-way but will be
planted on private property adjacent to the right-of-way. On storm sewer projects, trees may be
placed in disturbed work areas not adjacent to the right-of-way.
803 TREE STAKING
207
Original Date: 1/3/94
Revised Date: 05/27/16
Prior to the planting, the property owner will be provided, by the Resident Engineer, with stakes
marked with the tree type to allow the property owner to designate planting locations. It is the
Resident Engineer’s responsibility to tabulate the information received from the property owners
(type and number per address) and furnish this information to the nursery by letter.
804 INSPECTION REQUIRED
Points of inspection include checking tree type and planting practices. All trees and shrubs
should be inspected at the nursery and accepted for planting at this point. Holes for planting
should be dug 24 inches larger than the tree ball diameter and to a depth 6 inches greater than the
ball depth. All trees and shrubs should be fertilized with a 10-8-6 inorganic material at a rate of
1/4 to 1/2 pound per inch of diameter. All trees must be mulched over the backfill with 1 inch of
peat moss or 2 inches of rotten manure. Trees will be wrapped or staked depending on size – 3
inch trees will be wrapped and 2 inch or larger trees will be staked.
805 METHOD OF PAYMENT
The Resident Engineer will keep records of tree and shrub plantings by number and type. Since
this is a County contract, the nursery will invoice the County for payment. When the invoice is
received, it will be routed to the Resident Engineer to verify number and type planted and
accepted before final payment is made.
208
Original Date: 1/3/94
Revised Date: 05/27/16
SECTION 900
TRAFFIC SIGNALS AND TRAFFIC CODE
901 TRAFFIC SIGNALS IDENTIFICATION CODE
Traffic signal equipment specifications and construction procedures are included in the Special
Provisions because of the constant updating and improvement of signal equipment. The Division
of Traffic employs an identification code for all signal equipment items which are incorporated
into the bid item number and are useful when establishing items for Change Orders to determine
appropriate construction procedures.
The code is as follows:
(a) The first three digits will always be 904/905/906 and will refer to traffic signal equipment
items and procedures.
(b) The first set of two digits refers to a specific item or item location.
(c) The second set of two digits refers to specific size or specific type.
Since the bid item number is subject to change, the Resident Engineer will be required to check
the Special Provisions to obtain the proper identification code for the various signal component
items.
902 COORDINATION
The Resident Engineer should coordinate all signal work with the Division of Traffic personnel
and the prime contractor. On the majority of projects, the signal installation is done by a
subcontractor, and any revisions must go through the prime contractor.
The location of underground utilities is the first construction requirement when installing signals
on the project. Underground facilities, structures and utilities are usually not shown on the signal
plans. The contractor shall have the responsibility of locating these underground facilities,
structures and utilities.
The contractor shall notify the Resident Engineer and the Division of Traffic 48 hours in advance
when ready for the location of all signal equipment. The Resident Engineer should be present
when the Traffic Engineer spots the locations of post and cabinet bases, pull boxes, junction
boxes, and detector loops. The contractor shall not proceed with construction until these
locations have been spotted.
209
Original Date: 1/3/94
Revised Date: 05/27/16
903 CONSTRUCTION REQUIREMENTS
Construction of concrete bases for posts, mast arms and controller cabinets shall conform to the
dimensions shown on the Standard Drawings. The top surfaces of concrete aprons and Type B,
Type C, and Type P bases shall be flush with surfaced areas and approximately 1 inch above
seeded or sodded areas unless otherwise approved by the Engineer. The height above finish
grade of each Type D base shall be determined by the Traffic Engineer. Excavation for bases
shall be made in a neat and workmanlike manner, and the area must be barricaded to avert the
possibility of someone falling into the hole if left open overnight. Bases shall be formed from
the top of the base to a minimum of 12 inches below grade. The forms shall be level and shall be
held rigidly in place while the concrete is being placed. Concrete shall be Class B with air. The
placement of anchor bolts, conduit and ground rods shall be in accordance with the dimensions
as shown on the Standard Drawings and shall be carefully inspected and held rigidly in place
before and during concrete placement. The concrete shall be vibrated to fill all voids. Ground
rods placed in concrete pull boxes shall extend through bases into the ground. The contractor
shall protect anchor bolt threads during concrete pouring operations and remove any concrete
from the threads when finishing has been completed. All exposed surfaces of bases shall be
finished as soon as practical after forms have been removed. In addition, tops of bases shall be
finished level or to match the grade of the sidewalk, median, etc. where they will be located.
When installing reinforced plastic mortar junction boxes, make the top of the box flush with
surfaced areas and approximately 1 inch above surface in seeded or sodded areas. A drain of 1
inch clean gravel or crushed stone conforming to dimensions shown on the Standard Drawings
shall be constructed below each junction box.
Concrete pull boxes shall be Class B concrete, cast in place. Inside surfaces of pull box walls
shall be formed. Should the excavation be irregular, the outside walls shall also be formed. A
drain of 1 inch clean gravel or crushed stone conforming to the dimensions shown on the
Standard Drawings shall be constructed below each pull box. The top surface of each pull box
shall be flush with surfaced areas and approximately 1 inch above in seeded or sodded areas.
903.1 CONDUIT
Conduit may be installed either by trenching or pushing. The installation of all conduit will
require a minimum of 18 inches of cover unless otherwise shown on the plans. Any change in
direction of conduit will be accomplished by uniformly bending the conduit to a radius to fit the
location or by the use of standard bends or elbows. All conduit and fittings shall be free from
burrs and irregularities and cleaned prior to installation of cable. Be sure all fittings are tightly
connected with an approved bonding agent to the conduit. Any open ends of conduit placed for
future use shall be capped or plugged.
When conduit in trench is specified, trenches must be excavated to the width and depth necessary
for the installation of the conduit. No excavated material that will interfere with pedestrian
210
Original Date: 1/3/94
Revised Date: 05/27/16
traffic shall be placed in the street or on the sidewalk. When backfilling the conduit, make sure
the material is selected backfill, free of large rock or any other material that may damage the
conduit. In addition, the bottom of the trench shall be free of such material before any is placed.
The trench shall be backfilled in layers not to exceed 6 inches in depth, and each lift shall be
compacted to the same density as the adjacent material before the next lift is placed. All trenches
should be backfilled as soon as practicable due to the danger of someone stepping or falling into
them. The surface shall be replaced as nearly as possible to its former condition, any excess
material removed and the area left in a neat condition.
When pushed conduit is specified, the conduit shall be installed without disturbing the existing
surface unless otherwise approved by the Resident Engineer. Pushed conduit may be installed
by jacking, pushing, boring or other approved means. When existing pavement, shoulders,
sidewalk or curbing is removed and replaced to accommodate the boring operation, all repair
costs shall be borne by the contractor. If concrete sidewalk or pavement is broken or removed
during the operation, full slab replacement will be required. The push pit or receiving pit shall
be backfilled and compacted with the same requirements as open trench as explained in the
previous paragraph.
903.2 SIGNALS
The installation of steel mast arm pole and aluminum post with a square pedestal base requires
that they be securely fastened to a concrete base with anchor bolts. Aluminum posts with square
pedestal bases shall be erected vertically without the use of leveling nuts. Steel poles for
cantilever mast arms shall be installed plumb by adjustment of leveling nuts. Poles for cantilever
mast arms may be raked only when approved and directed by the Traffic Engineer. The gap
between the base plate of the pole and concrete base shall have wire mesh installed after final
adjustment of the leveling nuts is completed. Wood poles for span wire or power supply
installations shall be erected in accordance with the Standard Drawings.
All signal head assemblies shall be installed in accordance with the Standard Drawings unless
otherwise approved by the Traffic Engineer. Signal head fittings, brackets, terminal
compartments and hardware shall be securely tightened and fastened in position. Signal lenses
shall be covered or turned away from approaching traffic until turned on for normal operation.
When ready for normal operation, the signal heads shall be securely fastened in position and face
approaching traffic. The bottom of each beam mounted signal head shall not be less than 16 feet
nor more than 17 feet above the roadway surface. The contractor shall try to meet these criteria
by adjusting the height of each signal head on the mast arm in such a manner that the signal head
is approximately center of the traffic lane or lanes they control. They shall be aimed at a point
back of the stop bar at a distance corresponding to the following requirements: for an approach
speed of 30 mph, the distance shall be 160 feet; 40 mph, the distance shall be 240 feet and for 50
mph, the distance shall be 330 feet. The installation of loop detector cable requires a slot to be
sawed in the pavement as shown on the plans. The slot shall be thoroughly cleaned using
compressed air to blow out dirt and all free water prior to installation of cable. The slot shall be
2 inches deep in pavement.
211
Original Date: 1/3/94
Revised Date: 05/27/16
903.3 CABLES
The cable shall be pushed into the slot with blunt tools without damaging the insulation. After
the loop cable is spliced to the lead-in cable in the pull box and before the slot is sealed, the
resistance of the loop and lead-in cable to ground shall be checked. After a satisfactory test
which shows resistance of not less than 50 mega ohms, the slot shall be sealed with epoxy. The
epoxy shall be used in accordance with the directions of the manufacturer regarding the
preparation of the sealant mix, its application and the proper curing procedures prior to the
reopening of the road to traffic.
Installation of wiring:
(a) All signal cable runs shall be continuous, without splices, from the connections in the
terminal block of a signal head or disconnect hanger to the terminal strip in the
controller cabinet from one signal terminal block to another signal terminal block as
shown on the plans or as directed by the Traffic Engineer. All conductor cable
combinations to signal heads shall be as shown on the plans or as directed by the Traffic
Engineer.
(b) Power cable runs shall be continuous, without splices, from the power line switch located
on the service pole to controller cabinet terminals. Energized power cables shall run to
circuit breakers. The neutral cable shall be terminated on the ground bus bar in the
controller cabinet. The straned ground wire shall be terminated on the safety ground in
the cabinet. The contractor shall secure PVC conduit with stranded ground wire to the
service pole. The stranded ground wire shall be terminated to the ground rod installed
near the service pole.
(c) Push button and vehicle detector lead-in cable shall be connected to the controller by
separate No. 18 AWG, 2 conductor shield cable.
(d) Vehicle loop detector cable shown on the plans is an approximation of cable quantity
required to construct induction loops. Induction loop detector cables shall be installed in
accordance with manufacturer’s recommendations. The cable for detector loop will be
one continuous length from the loop to the adjacent pull box. In the pull box, the pair of
cables from each detector loop will be spliced to e lead-in cable. The lead-in cable runs
shall be continuous, without splices, from the pull box to the controller cabinet as shown
on the plans or as directed by the Traffic Engineer. All splices shall be made by
soldering 3M direct bury splice kits or by a method approved by the Traffic Engineer.
The pairs of conductors in the lead-in cables shall be wired in parallel and/or series.
The series relationship between detector loops shall not be accomplished by splicing the
lead-in cable conductors in a pull box or junction box. The lead-in cable for each
detector loop passing through pull boxes or junction boxes to the controller cabinet shall
not be coiled inside the boxes.
212
Original Date: 1/3/94
Revised Date: 05/27/16
(e) All signal posts and mast arm uprights shall be grounded by using a No. 6 AWG stranded
bare copper wire from the ground lugs inside the post or mast arm upright to a ground
rod with a ground wire clamp inside the nearest concrete pull box.
(f) Cables shall be pulled through conduit by a cable grip providing a firm hold on exterior
coverings. Cable shall be pulled with a minimum of dragging on the ground or
pavement. Frame mounted pulleys, or other suitable devices, shall be used for pulling
cables out of conduits into pull boxes and junction boxes. Lubricants may be used to
facilitate pulling cable. Slack in each cable shall be provided by a 6 foot loop in each
pull box and junction box.
(g) All wiring connections shall be securely tightened. Barrel lugs shall be used for all field
connections inside the controller cabinet. Insulated crimped-on connectors of an
approved type shall be used for all other terminal connections. All spare field wires shall
be capped with closed end insulated terminals of an approved type
(h) All signal interconnect and/or communication cable shall be continuous, without splices,
between traffic signal controllers and fiber optic cable termination cabinets unless
otherwise approved by the Traffic Engineer.
(i) Where possible, color codes shall be followed so that the red insulated conductor
connects to the red indication terminal, yellow to yellow, green to green and white to
neutral. The power cables shall be color coded so that black connects to AC (+) positive
and white to (-) neutral.
Conduit which is placed for future use shall be checked for proper alignment and
serviceability by having a pull string blown through from pull point to pull point and
trace wire installed for locating purposes.
(j) The installation of power supply assembly shall be in accordance with the Standard
Drawings. Any changes imposed by the utility company for connection, disconnection or
relocation of electrical service shall be borne by the contractor and included in the
contract unit price bid for each power supply assemble.
All traffic signal work performed by the contractor shall be maintained by the contractor prior to
final acceptance of new or modified traffic signal installations or removal of temporary traffic
signal installations. This maintenance shall include all repairs and/or adjustments determined to
be necessary due to malfunctions, construction operations, vandalism, knockdowns and/or acts of
God. The contractor shall be responsible for obtaining recovery of all damages including
replacement of any signal equipment.
In any event, if, in the opinion of the Director and at his sole discretion, immediate repairs and/or
adjustments are determined to be necessary to provide for the safe and efficient movement of
traffic and the contractor is not capable of making such repairs and/or adjustments to the
satisfaction of the Director, the Director will order County personnel or other qualified engineers
213
Original Date: 1/3/94
Revised Date: 05/27/16
or technicians to make immediate repairs and/or adjustments in the presence of the contractor.
The entire cost of the work performed by County or other qualified personnel, including the unit
bid price for the equipment used in repairs and/or adjustments will not be repaid until the total
project is accepted. The work performed by County or other qualified personnel will in no way
jeopardize any part of the guarantee.
904 SIGNAL OPERATION
When the contractor is certain all traffic signal equipment for a new or modified traffic signal
installation is operating properly, he shall make a request for inspection. After the inspection of
the signal equipment and the installation, the Traffic Engineer may authorize the contractor to
put the signal into permanent operation. Often this will be accomplished by placing the signal in
the flashing mode for a period specified by the Traffic Engineer prior to bringing the signal into
full operation. This authorization will be given if all signal equipment is working properly or if
public safety and convenience warrants the operation of the signal before all corrections have
been made. If the inspection reveals signal deficiencies, the contractor shall correct them
expeditiously and within the time allowed for the completion of the project. If the signal must be
put into flashing operation or completely shut down to make the necessary connections, the
contractor must receive approval from the Traffic Engineer before this action is taken. This
inspection procedure shall be repeated until all corrections have been made. No employee of this
Department shall assist the contractor in the handling of traffic to accomplish changes in signal
operations.
After all deficiencies have been corrected, the signal shall remain in operation for a 30
consecutive day test period. Any failure or malfunction of equipment during the test period shall
be corrected by the contractor, and then the equipment shall be retested for an additional 30
consecutive day period from day of correction. This procedure shall be repeated until the signal
equipment has operated to the Traffic Engineer’s satisfaction. When the signal is part of a
system within the project, that portion of the signal installation associated with the system’s
operation shall not be tested until all signals in the system within the project are ready to be
tested.
After a signal and/or signal system has been satisfactorily tested for 30 consecutive days, the
County will make emergency repairs and/or adjustments determined to be necessary due to
malfunctions; however, prior to final acceptance, the contractor shall still be responsible for any
repairs and/or adjustments determined to be necessary due to construction operations, vandalism,
knockdowns and/or acts of God.
Upon completion of the entire project, including completion of the signal test period, the
Department’s representative will make an inspection. If all construction required by the contract
has been completed according to the Specifications and to his satisfaction, that inspection will
constitute the final inspection. The contractor will be notified by the Department in writing of
the final acceptance.
905 METHOD OF MEASUREMENT
214
Original Date: 1/3/94
Revised Date: 05/27/16
(a) Measurement of conduit will be made to the nearest linear foot as indicated on the plans.
Contract quantities will be used in final payment, except field measurements will be made
when authorized changes are made during construction or where appreciable errors are
found in the contract quantity. The revision or correction will be computed and added to
or deducted from the contract quantity.
(b) Measurements of cable (conductors) will be made to the nearest 10 linear feet as
indicated on the plans. Contract quantities will be used in final payment. Field
measurements will be made when authorized changes are made during construction or
where appreciable errors are found.
The contract quantity listed below is a guide to be used when field measuring cable:
(1) Cable going into controller, add 10 linear feet for inside of controller.
(2) When measuring for post and mast arm from base of post to outermost signal head,
add 20 linear feet plus length of mast arm.
(3) On a side or top mount signal, add 15 linear feet.
(4) For a push button on post, add 5 linear feet from base.
(5) For a power supply, add 10 linear feet for pole.
(6) At junction boxes or pull boxes, add 6 linear feet for each box.
(7) For 1c #14 w/tube jacket add 3 linear feet for each pull box
(8) For Fiber Optic Cable add 10 linear feet for each single pull box
(9) For Fiber Optic Cable add 15 linear feet for each double pull box
(10) For Fiber Optic Cable add 20 linear feet for each controller cabinet
(11) For Video Cable add 35 linear feet for post extension camera mounting (except
Autoscope Brand)
(12) For Video Cable add 45 linear feet for mast arm camera mounting (except
Autoscope brand)
(13) For Video Cable add 45 linear feet for Luinaire arm camera mounting (except for
Autoscope brand)
(14) For Video Cable add 3 linear feet for all types of camera mountings(Autoscope
brand)
906 TRAFFIC CONTROL
215
Original Date: 1/3/94
Revised Date: 05/27/16
906.1 GENERAL
Problems of traffic control occur when traffic must be moved through or around road or street
construction, maintenance operations, utility work and incidents on or adjacent to the roadway.
No one standard sequence of signs or other control devices can be set up as an inflexible
arrangement for all situations due to the variety of conditions encountered.
Traffic conditions on streets are characterized by relatively low speeds, wide range of volumes,
limited maneuvering space, frequent turns and cross movements, significant pedestrian
movement and other obstructions. Construction, maintenance and utility operations are more
numerous and varied, including such diverse activities as pavement cuts for utility work,
pavement patching and surfacing, pavement marking renewal and encroachments by adjacent
building construction. Work on arterial streets should be restricted to off-peak hours to minimize
conflicts.
Although each situation must be dealt with individually, conformity with the established
provisions of the “Manual on Uniform Traffic Control Devices” (http://mutcd.fhwa.dot.gov/) is
required. The protection of the traveling public and the workmen on the scene will dictate the
appropriate measures to be taken.
Early project planning for traffic control in construction areas and implementation and
surveillance of these controls during construction is very important. To facilitate adequate
advance project planning, the plans and Specifications for each project should include provisions
for a reasonable, specific Traffic Control Plan for moving traffic through or around the
construction zone in a manner that is conductive to the safety of the traveling public, pedestrians
and workers. This Traffic Control Plan should include, but not be limited to, such items as
signing, application and removal of pavement markings, construction scheduling, methods and
devices for delineation and channelization, placement and maintenance of devices, traffic
regulations and surveillance and inspection.
906.2 RESPONSIBILITY
The provisions for public protection outlined herein are for application to the following:
(a) County forces performing construction or maintenance operations on roads and streets.
(b) Contractors employed in road or street construction or maintenance under contract to St.
Louis County.
(c) All others, including employees of public utility companies, fire departments and
enforcement officials or any contractor performing work within the public right-of-way
or so closely adjacent as to create hazards for the public or for themselves.
216
Original Date: 1/3/94
Revised Date: 05/27/16
906.3 FUNDAMENTAL PRINCIPLES AND PROCEDURES
Construction and maintenance areas can present unexpected or unusual situations to the motorist
as far as traffic operations are concerned. Principles and procedures that have effectively
enhanced the safety of motorists and workers in the vicinity of construction and maintenance
work areas are as follows:
(a) Traffic safety in and around roadway work areas should be a high priority element for an
project:
(1) The basic safety principles used to design permanent roadway improvements should
also govern the design of the work site. The goal is to route traffic through such
areas with a minimum of deviation from normal road or street conditions usually
encountered.
(2) A Traffic Control Plan should be prepared and understood by all responsible parties
before any work is begun. See example of Road Closure plan below:
ILLUSTRATION 906.3A – TYPICAL ROAD CLOSURE PLAN
(b) Traffic movement should be inhibited as little as practicable:
(1) Reduced speed zoning should be avoided if possible and usually will require an act of
the County Council to be enforceable.
(2) Changes in geometric, such as lane narrowing, dropped lanes or main line roadway
transitions should be used only when necessary.
(3) Provisions should be made for the safe operation of work or emergency vehicles.
217
Original Date: 1/3/94
Revised Date: 05/27/16
(4) Construction work should be scheduled to minimize the time when it interferes with
traffic flow. Typically, and depending on road ADT, daytime hours of 6am – 9am and
3pm – 6pm can cause significant traffic queueing and should be avoided if possible.
The engineer should evaluate the traffic patterns and volumes prior to authorizing
work during the above mentioned hours.
(5) Know and understand the components of a workzone, see figure below:
ILLUSTRATION 906.3B – WORKZONE COMPONENTS
218
Original Date: 1/3/94
Revised Date: 05/27/16
(c) Motorists should be guided in a clear and positive manner while approaching and
transversing construction and maintenance work areas:
•
The first
get their attention
•
The second
detailed information
•
The third
specific information
(1) Adequate warning, delineation and channelization by means of proper pavement
marking, signing and use of other devices effective under varying conditions of light
and weather should be provided.
ILLUSTRATION 906.3C – DELINEATION & CHANNELIZATION
219
Original Date: 1/3/94
Revised Date: 05/27/16
(2) Inappropriate existing markings should be removed or covered to eliminate any
misleading cues to the driver.
ILLUSTRATION 906.3D – EXAMPLE OF INAPPROPRIATE EXISTING PAVEMENT
MARKINGS
(3) Flagging procedures should be employed only when other methods of traffic control
are inadequate.
ILLUSTRATION 906.3E – TYPICAL FLAGGING PROCEDURES
220
Original Date: 1/3/94
Revised Date: 05/27/16
(d) Routine inspection of traffic control elements performed by the Resident Engineer:
(1) The Resident Engineer, his assistants and inspectors and contractor’s superintendent
should ensure that all traffic control elements of a project conform to the Traffic
Control Plan. All safety devices should be checked twice per day and as often as
encountered during the course of the day. These checks should be noted in the
Resident Engineer’s Daily Diary, and any corrections made should also be noted.
(2) The work site should be carefully monitored under varying conditions of traffic, light
and weather to ensure that the traffic control measures are operating effectively.
(3) All traffic control devices shall be removed immediately when no longer needed.
(e) The maintenance of roadside safety requires constant attention during the life of the
construction zone:
(1) Channelization of traffic should be accomplished by the use of pavement markings
and signing, flexible posts, barricades and other lightweight devices which will yield
when hit by errant vehicles. Damaged or manipulated devices should be replaced
immediately by the contractor at this own cost.
The following are examples of worn and/or damaged devices that need replaced:
ILLUSTRATION 906.3F – EXAMPLE OF FADED SHEETING & CHIPPED/PEELING
LETTERING
ILLUSTRATION 906.3G – EXAMPLES OF IMPROPERLY INSTALLED AND/OR
MANIPULATED TRAFFIC CONTROL DEVICES
221
Original Date: 1/3/94
Revised Date: 05/27/16
Improperly installed and/or manipulated devices shall require immediate work stoppage until
corrections are made to the satisfaction of the engineer.
(2) Construction equipment, materials and debris should be stored in such a manner as
not to be vulnerable to run-off-the-road vehicles.
907 SIGNS
907.1 DESIGN
Street or highway construction and maintenance signs fall into three major categories:
Regulatory Signs, Warning Signs and Guide Signs. Special construction and maintenance signs
follow the basic standards for all highway signs as to shape, size and color. Warning signs in
construction areas shall have a black legend on an orange background. Existing yellow warning
signs already in place within these areas may remain in place. The use of standard orange flags
or yellow flashing warning lights in conjunction with signs is allowable as long as they do not
interfere with a clear view of the sign. The dimensions of the signs shall be standard. Smaller
size signs may be used when authorized and shall deviate from standard sizes in 6 inch
increments. The signs should be in accordance with accepted standards and mounted as
prescribed on the Traffic Control Plan.
907.2 ILLUMINATION / REFLECTORIZATION
222
Original Date: 1/3/94
Revised Date: 05/27/16
All signs intended to be used during hours of darkness shall meet the minimum AASHTO
criteria and be fluorescent retroreflective sheeting, TYPE VIII minimum. See chart below for guidance:
ILLUSTRATION 907.2A –REFLECTIVE SHEETING MATERIALS REFERENCE
Street lighting is not regarded as adequate for sign illumination. The following picture is a good
example of what proper workzone signage material should look like:
ILLUSTRATION 907.2B – PROPER STORAGE OF WORKZONE SIGNAGE
223
Original Date: 1/3/94
Revised Date: 05/27/16
907.3 POSITION OF SIGNS
Signs shall be placed in positions where they will convey their messages effectively so that the
driver will have adequate time for response.
As a general rule, signs shall be placed on the right hand side of the roadway. Where special
emphasis is necessary, dual installation of signs on opposite sides of the roadway may be made.
Within a construction zone, however, it is often necessary and/or desirable to erect signs on
portable supports placed within the roadway itself. It is also permissible to mount signs on
barricades during daytime operations.
Signs shall be erected a minimum of 2 feet lateral clearance and 7 feet vertical clearance is
necessary. Signs mounted on barricades or temporary supports may be as low as, but not less
than, 1 foot above the pavement surface.
ILLUSTRATION 907.3 – WORKZONE SIGNAGE POSITIONING
Where roadway conditions permit, in advance of the work site, warning signs should be placed
approximately 1,500 feet in front of the condition to which they are calling attention. When a
series of warning signs are used, they should be placed at 500 to 1,000 foot intervals, with the
warning sign nearest the work site 500 feet from the point of restriction. On local streets, where
more restrictive conditions prevail, approach warning signs may be placed at closer intervals
(100 to 500 feet).
907.4 ERECTION OF SIGNS
Signs on fixed supports are usually mounted on a single post, although those wider than 3 feet
should be mounted on two posts. Signs can also be mounted on portable supports, and both
fixed and temporary installations should be constructed to yield upon impact to minimize
hazards to motorists.
224
Original Date: 1/3/94
Revised Date: 05/27/16
For mobile operations, such as pavement marking, signs and/or flashers and lights may be
mounted on a vehicle or trailer.
908 TYPES OF SIGNS
908.1 REGULATORY SIGNS
Regulatory signs impose legal obligations and/or restrictions on all traffic. They are generally
rectangular and carry a black legend and border on a white background (“Speed Limit” signs,
“Do Not Pass” signs, etc.). Some expectations are the “Stop”, “Yield” and “Do Not Enter” signs
which are not all rectangular and carry a white legend and border on a red background.
ILLUSTRATION 908.1 – EXAMPLES OF REGULATORY SIGNAGE
When construction operations require regulatory measures different from those normally in
effect, the existing permanent regulatory devices shall be removed or covered and replaced by
the appropriate temporary regulatory sign.
The “Road Closed” sign shall be used where the roadway is closed to all traffic except
contractor’s equipment and authorized vehicles and shall be accompanied by appropriate detour
signing. The sign shall be erected near the center of the roadway on or above a barricade that
closes the roadway and shall be a minimum of 48 X 30 inches in size.
The “Local Traffic Only” sign should be used where through traffic must detour to avoid a
closed road some distance beyond but where the road is open up to the point of closure. It shall
carry the legend “Road Closed”, “Local Traffic Only” and shall be accompanied by appropriate
detour signing. The words “Bridge Out” may be substituted for “Road Closed” where
applicable.
908.2 WARNING SIGNS
225
Original Date: 1/3/94
Revised Date: 05/27/16
Warning signs for construction and maintenance projects are used to notify drivers of specific
hazards or conditions they may encounter such as closed lanes or detours. They shall generally
be diamond shaped (square with one diagonal vertical) having a black symbol or message on an
orange background. Rectangular shapes are also used, though less often.
908.3 ADVANCE WARNING SIGNS
Various circumstances will occur which require extra advance warning and may include a series
of warning signs, including distances that can be shown on the sign itself or just below it as a
separate advisory panel. Most warning signs may be used in repetition with appropriate legends,
or in conjunction with other construction signs. As an alternate to specific distances, the word
“Ahead” may be substituted for advance warning signs.
ILLUSTRATION 908.3 – EXAMPLES OF ADVANCED WARNING SIGNAGE
(a) The “Road Construction Ahead” sign is to be located in advance of the initial
construction or detour as a general warning of obstructions or restrictions.
(b) The “Road Closed Ahead” sign is intended for use in advance of a point where a
roadway is closed to all traffic or to all but local traffic.
(c) The “One Lane Closed Ahead” sign is intended for use only in advance of a point where
traffic in both directions must use a single lane. If the one lane stretch is long enough so
it is not visible throughout from either end, provision must be made to move traffic
alternately from each end under control.
226
Original Date: 1/3/94
Revised Date: 05/27/16
(d) The “Advance Lane Closed” sign is intended for use where applicable in advance of a
point where one lane of a multiple-lane roadway is closed. It carries the legend: “Right
(Left) Lane Closed Ahead”.
(e) The “Advance Flagger” sign is intended for use in advance of any point at which a
flagger has been stationed to control traffic through a construction or maintenance
project. It carries the legend, “Flagger Ahead”. The flagger symbol sign may be used
as an alternative to the worded message. The sign shall be promptly removed or covered
when there is no flagger present.
908.4 MAINTENANCE AND MINOR CONSTRUCTION WARNINNG SIGNS
At many maintenance and minor construction operations, particularly on lightly traveled roads, a
sequence of advance warning signs may not be needed. The following signs listed and described
will ordinarily provide sufficient warning to motorists and may also be needed inside the limits
of a major work area where traffic is maintained through the job.
(a) A “Road Construction Ahead” sign should be used for the protection of personnel
working in or near the roadway on minor maintenance and public utility projects such as
telephone, sewer and electrical service work.
(b) The “Fresh Oil” sign is intended to warn motorists that resurfacing operations have
rendered the pavement surface temporarily hazardous, and splashing on vehicles may
occur.
(c) The “Road Machinery” sign is used in advance of areas where machinery is working in
the roadway.
(d) The “Road Work” and “Shoulder Work” signs should be used ahead of maintenance or
minor construction operations involving the shoulder or roadway edge.
(e) The “Survey Crew” sign is used in advance of an area where a Survey Crew is working
in or adjacent to the roadway.
Other warning signs that can be applied to construction or maintenance work areas include the
following:
(a)
(b)
(c)
(d)
(e)
(f)
(g)
(h)
Large Arrow
Road Narrows
Bump (Dip)
Pavement Ends
Soft Shoulder (Low Shoulder)
Rough Road
Be Prepared to Stop
Chevron Panels
When used for such applications, these signs should have black legends and orange background.
908.5 WARNING SIGNS FOR BLASTING AREAS
227
Original Date: 1/3/94
Revised Date: 05/27/16
As sources of radio-frequency can cause premature firing of electric blasting caps used in
construction operations, the Institute of Makers of Explosives Publication No. 20, “Radio
Frequency Energy, A Potential Hazard in the Use of Electric Blasting Caps,” should be consulted
for guidelines for safe operations. A sequence of warning signs is recommended for use where
blasting operations are taking place in the vicinity of a traveled roadway.
(a) The “Blasting Zone” (1000) feet sign is intended for use in advance of any work site
where there are explosives being used. It shall follow the normal warning sign shape and
color.
(b) The “Turn Off 2-Way Radio” sign is to be used in conjunction with the “Blasting Zone”
sign, but shall have a rectangular shape.
(c) The “End Blasting Zone” sign is used to define the limits of the danger area. It also is
rectangular in shape and should be placed a minimum of 1,000 feet beyond the blasting
zone, either with or preceding the “End Construction” sign.
908.6 GUIDE SIGNS
Some informational and guide signs are necessary in and around construction zones, the most
prominent being length of construction area and detour signing. They shall be rectangular with a
black legend and orange background.
(a) The “Road Construction Ahead” sign should be erected at the limits of any road
construction or maintenance job where traffic is maintained through the work area. It
can be mounted on a barricade as well as on posts.
(b) The “End Construction” sign should be erected approximately 500 feet beyond the end of
a construction or maintenance job. It may be mounted on the back of a barricade or
warning sign facing the opposite direction of traffic where it is convenient to do so. The
legend “End Road Work” is also acceptable.
ILLUSTRATION 908.6A – EXAMPLE OF END CONSTRUCTION/END ROAD WORK
SIGN
(c) The “Detour Arrow” sign is used at the point where a detour roadway or route has been
established due to a closure of a street or road to through traffic. It is normally mounted
below or next to the “Road Closed” or “Local Traffic Only” sign on a barricade. The
“Detour Arrow” sign uses a horizontal arrow pointed to the right or left as required.
228
Original Date: 1/3/94
Revised Date: 05/27/16
ILLUSTRATION 908.6B – EXAMPLE OF DETOUR SIGNAGE ON BARRICADE
Each detour shall be adequately marked with temporary detour arrows and destination signs and
is the responsibility of the County on contract projects. The “Detour” sign is used for short
distances where markers are unnecessary along the detour to guide traffic around the
construction.
For examples of construction, guide, warning and detour signing, the “Uniform Manual on
Traffic Control Devices” should be consulted.
909 CHANNELIZING DEVICES
The function of channelizing devices is to alert drivers to hazards created by construction
activities in or near the roadway and direct them safely past these hazards. Channelizing devices
normally used for construction projects include cones, channelizers, vertical panels, barricades
and barriers. These devices should provide a smooth and gradual transition for traffic moving
from one lane to another, onto a detour or in reducing the traveled roadway width.
The most important and commonly used element for traffic channelizing devices in construction
areas is the taper. Improperly laid out, the taper can cause unsafe traffic conditions with
resulting congestion and possible accidents through the work area. The minimum desirable taper
length should be computed by the formula L=WS2/60 for speeds of 40 mph or less and L=WS in
excess of 45 mph, where L equals the length of the taper in feet, S equals the posted speed limit,
and W equals the closed lane or offset width in feet. This length can be adjusted due to factors
229
Original Date: 1/3/94
Revised Date: 05/27/16
such as inadequate sight distance on a curve or proximity of the work to entrances, intersections,
etc. Maximum spacing of the devices used in a taper should approximately equal the speed limit
in feet. (Example: 30 mph – 30 feet apart.)
On construction projects, channelization may remain in place for long periods of time. During
such a long interval of time, some of the devices (cones, barricades, channelizers, etc.) as well as
some signing can become dislodged or moved from their original placement. It is, therefore,
necessary for the Resident Engineer to inspect on a daily basis all of the elements of the Traffic
Control Plan to ensure the safety of the motorists and the workers. It is also desirable to mark
safety device locations to aid replacement of dislodged or destroyed devices. Ballast consisting
of loosely filled sandbags shall be added to all traffic control devices to prevent them from
blowing over, but this should be done in such a way that they do not become projectiles if struck
by traffic.
909.1 CONES
Traffic cones and tubular markers are available in various sizes for roadway use. They should be
a minimum of 36 inches in height, orange in color, and made of lightweight, flexible material
able to withstand impact without damage to themselves or to vehicles. For nighttime use, 6 inch
reflectorized bands should be placed on them. Cones are best suited for use in temporary
applications in traffic, such as lane closures due to machinery or road work, where they can
easily be set up, moved and taken down in a short period of time. If the cones are frequently
knocked over by wind from passing vehicles, weights can be added to their bases for increased
stability. Also, orange flags can be inserted in the top of the cone for better daytime visibility.
ILLUSTRATION 909.1 – TRAFFIC CONE DIMENSIONS
909.2 VERTICAL PANELS
Vertical panels used for channelization purposes shall be 8 to 12 inches in width, a minimum of
24 inches in height, carry alternating reflectorized orange and white stripes 4 to 6 inches wide
sloping 45 degrees, and be a minimum of 3 feet above the roadway. They are normally used for
traffic separation or shoulder barricading where space restrictions occur. For use on the right
230
Original Date: 1/3/94
Revised Date: 05/27/16
side of the roadway, the stripes shall run from the upper right to the lower left and on the left side
of the roadway, from the upper left to the lower right.
ILLUSTRATION 909.2 – VERTICAL CHANNELIZATION PANELS
909.3 CHANNELIZERS
Drums used for traffic channelization shall be constructed of plastic, approximately 3 feet in
height and 18 inches in diameter with alternating horizontal reflectorized orange and white
stripes 4 inches to 6 inches wide. They are commonly used to channelize or delineate traffic
flow but may also be used to mark specific hazards. Channelizers are portable but generally are
placed where they will remain in place for a prolonged period of time. Small arrow signs or
vertical panels can be mounted above the channelizers to supplement delineation, but added
weight in the channelizers should not be used in traveled roadway applications.
ILLUSTRATION 909.3 – EXAMPLES OF CHANNELIZER TYPES
231
Original Date: 1/3/94
Revised Date: 05/27/16
909.4 BARRICADES
Barricades can be either portable or fixed, having from one to three rails with appropriate
striping and are used to control traffic by closing, restricting or delineating all or a portion of the
roadway right-of-way. They shall be one of three types (Type I, II, or III) depending on their
usage and application.
The striping shall consist of alternating orange and white reflectorized stripes (4 to 6
inches wide) for the rails slope on a 45 degree angle to the left or right away from the work in the
direction the traffic should follow. Normally, barricades are made of wood with A-Frame type
bracing for larger ones (Type III) and with metal legs and wood rails for smaller sizes (Types I
and II). When used in traffic, sandbags should be added on the lower part of the frame to
prevent the barricades from being knocked over or moved out of position. The name of the
contractor or supplier may be shown only on the back side of the barricade rails.
ILLUSTRATION 909.4A – EXAMPLES OF TYPE I & II BARRICADES
Where traffic is to be maintained through the construction zone, Type I or Type II barricades
should be used, singly or in groups, to channelize traffic or mark specific hazards. Maintenance
operation, utility and emergency work usually requires these barricades. When a road section is
closed to traffic, Type III barricades shall be erected at the point of closure and may extend
completely across the roadway. Type II barricades should be used ahead of this point if local
traffic, but not through traffic, is to be maintained. Appropriate detour and road closed signing
should accompany these barricades. The Resident Engineer should make sure the contractor
maintains the barricades in their proper positions when access is required to the job with
equipment and they are moved frequently.
ILLUSTRATION 909.4B – EXAMPLE OF TYPE III BARRICADES
Barricades used with reflectorized taping can also mark paths for pedestrians through and around
construction zones where sidewalks may be temporarily inaccessible.
232
Original Date: 1/3/94
Revised Date: 05/27/16
For nighttime conditions, flashing and steady burn lights can be added to barricades for higher
visibility and aid in channelization.
909.5 PORTABLE BARRIERS
909.5 PORTABLE BARRIERS
Barriers are designed to prevent vehicles from leaving the roadway and traveling into a
construction zone or hazardous area while minimizing damage to an impacting vehicle and its
occupants. They may be constructed of concrete or metal so that they physically deter access of
vehicles to portions of the right-of-way. Barriers may also serve to channelize traffic and, in
such usage, shall be supplemented by standard channelization or delineation markings. The
effects of impacting the ends of the barrier should be minimized by flaring the ends away from
the travelway and by using crash cushions.
ILLUSTRATION 909.5 – EXAMPLES OF TYPE PORTABLE BARRIERS
233
Original Date: 1/3/94
Revised Date: 05/27/16
910 MARKINGS
When construction work necessitates the use of vehicle paths other than those normally used, a
check drive through should be made to evaluate the possibility that existing pavement markings
might lead drivers from the intended path. Inappropriate or misleading markings should be
removed and new delineation placed before allowing traffic through. The intended vehicle path
should be clearly defined for day, night and twilight periods under both wet and dry conditions.
Where temporary roadways are constructed to by-pass a closed portion of the road or the vehicle
path will be of a short duration, pressure sensitive traffic marking tape or raised pavement
markers may be used in place of reflectorized paint to mark the lanes.
ILLUSTRATION 910 – EXAMPLES OF TEMPORARY PAVEMENT MARKINGS
Maintenance activities normally do not require pavement markings, as they can be accomplished
in one or more continuous shifts and are adequately protected by warning signs, flaggers and
other channelizing devices.
911 DELINEATORS
Delineation in a construction and maintenance zones is intended to be a guide to indicate the
alignment of the roadway and to outline the required vehicle path through these areas.
Delineators are not to be used as warning devices.
234
Original Date: 1/3/94
Revised Date: 05/27/16
ILLUSTRATION 911 – EXAMPLES OF DELINEATORS
Delineators are retroreflective units capable of clearly reflecting light under normal
atmospheric conditions from a distance of 1,000 feet when illuminated by the upper beam of
standard automobile lights. Reflective elements for delineators shall have a minimum dimension
of 3 inches.
Delineators, when used, shall be mounted on suitable supports so that the reflecting unit is about
4 feet above the near roadway edge. The standard color for delineators used along the right side
of streets and highways shall be white. The color of delineators used along the left edge of
divided streets and one-way roadways shall be yellow. Spacing along roadway curves should be
such that several delineators are always visible to the driver.
912 LIGHTING DEVICES
Construction and maintenance activities often create conditions that are particularly hazardous at
night. It is desirable and necessary under such conditions to supplement the reflectorized signs,
barricades and channelizing devices with lighting devices.
The three types commonly used are:
(a) Floodlights for construction work or maintenance operations have a limited but
important application. When high volume traffic conditions or the nature of the work
being performed require a nighttime shift, floodlights become necessary. The job site
should be well lit so that the workmen can see what they are doing and the passing
motorists can see them. The lighting placement can best be determined by driving
through the site and observing the floodlight area. Care should be taken not to create
glare in the eyes of the passing drivers.
(b) Flashing and steady burn warning lights are portable, lens directed, enclosed lights
whose color shall be yellow and are available in three variations. They have minimum
mounting height of 36 inches above the roadway surface to the bottom of the lens. Type
A warning lights are flashing low intensity lights, most commonly mounted on
barricades, drums, vertical panels and advance warning signs. They operate on a dusk
to dawn cycle. Type B warning lights are flashing high intensity lights normally mounted
on advance warning signs or independent supports or on barricades for extremely
hazardous work site conditions. They are designed to operate 24 hours per day. Type C
235
Original Date: 1/3/94
Revised Date: 05/27/16
warning lights are steady burn lights used to delineate the edge of the roadway on detour
curves, lane changes, lane closures and other similar conditions. They can be mounted
on barricades, drums or other channelizing devices and operate dusk to dawn.
(c) Advance warning arrow panels are special lighting units that are generally trailer
mounted for easy transport and are operated from a self contained power source on the
trailer, either batteries or a power driven electric generator. They may be used for day
or night activities, either construction or maintenance, and are particularly effective
where the work is being conducted on a high density roadway. Arrow panels provide
additional advance warning and are used in conjunction with necessary signs, barricades
and other traffic control devices. They are available in 3 sizes ranging from 24 x 48
inches to 48 x 96 inches with the panel face finished non-reflective black and a minimum
of 12 to 15 lamps flashing at a rate of not less than 25 times per minute. Minimum
legibility on a clear day or night should be no less than 1/2 to 1 mile, depending on the
size of the panel.
913 FLAGGING AND HAND SIGNAL PROCEDURES
The most common hand signaling devices used in controlling traffic through work areas are the
red flag and “Stop-Slow” paddle. Flags should be a minimum of 24 x 24 inches and made of a
good grade synthetic material, red of bright orange in color. Sign paddles should be at least 18
inches wide with letters 6 inches tall, fabricated from sheet metal with a rigid handle. The
background of the “Stop” face shall be red with white borders and letters. The background of the
“Slow” face shall be orange with black borders and letters. For use at night, the sign shall be
reflectorized.
ILLUSTRATION 909.4A – FLAGGING & HAND SIGNAL PROCEDURES
The sign paddle bearing the clear messages “Stop” or “Slow” provides motorists with more
positive guidance than flags and should be the primary hand signaling device. Flag use should
be limited to emergency situations and at spot locations which can be best controlled by a single
flagger.
236
Original Date: 1/3/94
Revised Date: 05/27/16
SECTION 1000
MATERIALS TESTING
1001 GENERAL
The purpose of materials testing is to provide assurance of compliance on stipulated quality of
materials, as specified in the Specifications and the Special Provisions, used in the various
construction phases. For the necessary quality control on a County Project, this materials testing
may be divided into three categories: Field Testing, County Laboratory Testing and testing by
other agencies.
All materials provided for the construction of the project are subject to inspection and may be
accepted or rejected either totally or in part. The contractor will comply completely in the
testing of materials and will solicit the aid of material suppliers and producers to facilitate on-site
inspections.
Testing will be performed in accordance with accepted procedures and at a frequency which will
ensure uniformly acceptable results. In general, testing procedures will follow either American
society for Testing and Materials (ASTM) or American Association of State Highway and
Transportation Officials (AASHTO) guidelines. These updated procedures are available for
reference at the Materials Testing Laboratory.
The Materials Engineer is the contact person for the acquisition of testing materials and
apparatus, for test results performed by the laboratory personnel and for scheduled inspection of
materials produced on a daily basis. Call 314-615-1187 (Materials Order Desk) between 2:30 and 3:15
pm of the work day before inspection is needed (2 days for nightwork, weekends or holidays). Major
operations which will require extensive inspection (i.e. bridge deck pour, main line paving, etc.)
should be coordinated at least one week in advance of the work.
The assignment of Materials Testing Laboratory inspection personnel will be under the direct
supervision of the Materials Engineer; however, it will be the responsibility of the Resident
Engineer to communicate with the plant inspector while attempting to establish uniformly
consistent material from a given source. Should a major problem arise in the quality or
uniformity of the material being used, the Materials Engineer should be contacted immediately.
1002 FIELD TESTING
On site testing is performed to provide the Resident Engineer with information which will direct
his judgment as to the quality of operations being performed by the contractor. The testing
should be performed in a manner which will provide accurate and timely results. Ideally, each
person on the project should be qualified to complete the materials testing required.
237
Original Date: 1/3/94
Revised Date: 05/27/16
The Resident Engineer may designate one inspector to be in charge of all materials testing and
the recording of all results in the Materials Testing Book. The Inspector should report all results
to the Resident Engineer and provide him with copies of materials testing reports for the Project
Files and to be forwarded to the Materials Engineer. The Resident Engineer should be
thoroughly familiar with all testing procedures and requirements. He should be able to recognize
the sources of error which may affect test results. The Resident Engineer should oversee the
testing performed by inspection personnel and should periodically check testing procedures for
conformity to specified procedure. The minimum field schedule for testing is shown in Table
1017B.
1003 SOILS TESTING
Obtaining Soil Samples by Resident Engineer.
At the commencement of the project, the Resident Engineer should, with the assistance of the
contractor, obtain soil samples which will be representative of the soil on the project to be
incorporated into the embankments. These samples should not contain organic material and
should be taken at locations on the project within the right-of-way and at elevations which will
be reached during the course of roadway construction. A separate sample will be required from
each borrow site that is used on the project. A canvas sample bag may be obtained at the
Materials Testing Laboratory, and an average sample will weigh about 50 pounds. The sample
should be properly labeled (Project No., Location, Date and Quantity) and delivered to the
Materials Testing Laboratory to be used to establish a Standard Proctor for density control, along
with the liquid limit and the plastic index of the individual soil. (See County Laboratory
Testing.) Approximately 5 to 7 working days will be required to obtain these desired results.
Aggregate samples for testing will be acquired by Materials personnel.
1003.1 EQUIPMENT REQUIRED
The preferred modern method to determine soil compaction is with the Troxler or Humboldt
Nuclear Density Gauge Device. Users are required to take an annual Radiation Safety training
course prior to being authorized users of the device. Training sessions are typically in February
or March of each year and provided by the Materials Lab.
238
Original Date: 1/3/94
Revised Date: 05/27/16
ILLUSTRATION 1003.1A – NUCLEAR DENSITY GUAGE
An alternate way of determining field density is by way of the Sand Cone Test.
See You Tube Video below (or follow instructions detailed below)
https://www.youtube.com/watch?v=ojH0W3xq3P0
ILLUSTRATION 1003.1B – SAND CONE DENSITY TEST
The following equipment is required for obtaining samples for density determination by the sand
cone method:
(a) Sand cone density apparatus (obtain at Materials Testing Laboratory).
(b) 10 kgm balance and 500 gm balance with weights (obtain at Materials Testing
Laboratory). Both balances should be zeroed before any testing is performed. Balances
should remain undisturbed and checked before each test.
239
Original Date: 1/3/94
Revised Date: 05/27/16
(c) Heating unit (obtain at Materials Testing Laboratory).
(d) Sample drying pan (obtain at Materials Testing Laboratory).
(e) Sugar scoop, large spoon, screw driver with long shank, pliers and gallon sample can
with lid (obtain at materials Testing Laboratory).
(f) Silica Sand (obtain at Materials Testing Laboratory).
1003.2 FIELD DENSITY TEST BY SAND CONE METHOD
The field density test is used to relate the density of a given sample to that of a standard sample
having a fixed moisture content which has been compacted by a specified force. In this test, the
moisture content and compactive force are variables which are graphically illustrated in the soil
proctor curve. (See County Laboratory Testing.) This density test applies equally to soils and
aggregate base courses.
The Sand Cone Method (AASHTO T-191-61) is used to determine density as specified in the
Specifications.
Results obtained from this test will depend upon the following factors:
(a) Particle size and physical properties of the material.
(b) Moisture content of the soil
(c) Type and amount of compactive effort expended.
The liquid limit, plastic limit and plasticity index are measures of the quality of the soil to be
used. The Standard Proctor curve provides a maximum soil density with minimum compactive
effort at moisture content considered “optimum” for the soil to be used. These factors will
provide the basis for determining the quality of any embankment construction.
The following testing procedures should be observed in conducting a moisture-density
determination:
(a) The silica sand used to fill the excavated sample void must be calibrated to obtain an
accurate mass. This calibration is performed at the Materials Testing Laboratory.
(b) The cone of the sand cone apparatus must also be calibrated to determine the weight
when filled with the silica sand.
This calibration is performed as follows:
(1) Fill the sand cone apparatus with silica sand.
(2) Using the 10 kgm balance – weigh the sand cone apparatus and record the weight.
240
Original Date: 1/3/94
Revised Date: 05/27/16
(3) Place sand cone in sample pan, open valve and allow cone to fill. (Caution: Do not
vibrate table or assembly, as a false reading will result.)
(4) Close valve and remove sand cone apparatus.
(5) Weight sand cone apparatus and remaining sand. The difference is the weight of
sand in the cone. (Note: By knowing that the volume of the cone is nearly .037 cubic
feet, a double check of the calibration weight of the silica sand is possible.
Calibrations are vital for accurate results and should be performed when sources of
silica sand are changed or test results become erratic.
(c) The following procedure should be utilized in performing the Sand Cone Method
(AASHTO T-191-61) test:
(1) Preparatory to the test, County Form 4505, “Field Density,” should be obtained at
the Materials Testing Center Laboratory.
The known quantities should be entered on the form. Line 7 is calibrated weight of
sand in cone (determined in Step 2), Line 9 is calibrated weight of sand (determined
in Step 1) and Line 20 is maximum dry density as provided in Standard Proctor curve
information.
(2) The sand cone apparatus should be filled with calibrated sand. Approximately 14 to
16 pounds of sand should be required per test. Weigh the total sand and apparatus
and enter on Line 4 of the form.
(3) Weigh the empty gallon sample can with lid and enter on Line 2 of form.
(4) The location of the test volume sample should be carefully selected. The intent of this
test is to provide a representative view of the compactive effort being provided by the
contractor. Unstable areas and obviously well-compacted areas should be by-passed
in favor of an area which represents the general condition of the embankment. Once
determine, the station location and distance left or right of centerline should be
obtained and recorded. The approximate elevation of the sample being taken should
also be obtained. Loose dirt and rock should be removed and a test site of 2 x 2 feet
minimum leveled for testing.
(5) Seat inverted sand cone apparatus on leveled surface and mark outline of cone.
Remove sand cone apparatus.
(6) Beginning at the center of the outlined area, loosen and remove material and place in
sample can. Care should be taken to keep the material adjacent to the outline from
becoming dislodged. A volume of 0.05 cubic feet should be removed from the area.
This will translate to a 6 inch diameter hole 4 inches in depth. The walls of the hole
should be as vertical and smooth as possible. Any non-typical material (i.e. rock,
roots, etc.) should be removed during sample removal but replaced when sample
taking is completed. The hole should be cleaned of as must loose material as
possible. All sample material should be placed in the sample can with care taken to
maintain the total sample. The can should be kept covered as much as possible to
prevent moisture loss. Seal sample can when completed.
241
Original Date: 1/3/94
Revised Date: 05/27/16
(7) Invert sand cone apparatus and seat over sample hole being careful not to dislodge
any material into the sample volume hole. Open the valve and allow sand to fill the
sample volume hole and sand cone. (Note: Vibration from nearby equipment will
affect test results – perform tests away from earth moving or compaction equipment.)
(8) Close valve in sand cone apparatus (be sure valve is completely closed). Remove test
apparatus to Project Office and weigh, recording results on Line 5 of the test form.
Also weigh sample in sample can with lid and record result on Line 1 of test form.
(9) By deducting Line 2 (weight of can with lid) from Line 1 (weight of sample and can),
the weight of the sample may be determined (line 3). By deducting Line 5 (final
apparatus weight) from Line 4 (initial apparatus weight), the weight of sand required
to fill the sand cone and sample volume hole may be obtained (Line 8). By dividing
the weight of sand required to fill the sample volume hole (Line 8) by the calibrated
unit weight of sand (Line 9), the volume of the sample hole (Line 10) may be
obtained. By dividing the sample volume weight (Line 3 or 17) by the volume of the
sample volume hole, a wet density may be obtained (Line 18).
1003.3 MOISTURE CONTENT DETERMINATION
In order to complete the density test procedure, it is necessary to perform another field testing
procedure – the Moisture Content Determination. This test is used to indicate the percentage of
moisture in a given sample of material. This test has application not only to the density
determination but is also used in determining aggregate moisture correction factors for watercement ratios and for placing of certain bituminous products.
The following procedure should be followed to make a moisture content determination:
(a) Using the 500 gram balance, determine the empty weight of the sample pan and record
same on Line 13 of Form 4505.
(b) Unseal sample can and place 300 to 400 grams of material in sample pan and establish
wet weight (record on Line 11). (Note: Be sure sample is not segregated – a
representative sample is required. The sample should be obtained from various areas
within the can in order to ensure the sample is representative).
(c) Place sample on heating unit and evaporate water from sample (using medium heat
setting on unit).
(d) When all moisture is gone from sample (check dryness with a watch glass), weigh sample
and record on Line 12. (Note: Observe cooled sample on balance – sample should
become heavier as moisture from air is re-absorbed – this will provide a check on
dryness of sample for weighing).
(e) Obtain moisture weight by subtracting dry weight of sample and pan (Line 12) from wet
weight of sample and pan (Line 11). Obtain dry weight of sample by deducting weight of
pan (Line 13) from dry weight of sample and pan (Line 12). Obtain percentage of
242
Original Date: 1/3/94
Revised Date: 05/27/16
moisture by dividing moisture weight (Line 14) by dry weight of sample (Line 15)
multiplied by 100 to express a percentage.
As moisture content is a variable quantity in the density testing procedure, a comparison to
“optimum moisture” for the specified material should be made. If the moisture determination for
a given sample varies by more than + percent, compactive effort will have to be increased to
obtain the required degree of density. The contractor should be notified when this condition
occurs. When the moisture content of a soil sample is measured at 2 or more percentage points
below optimum moisture, the contractor will find is beneficial to add water as he placed
embankment. If the moisture content of the soil sample exceeds the optimum moisture level by
more than 2 percentage points, the contractor will probably be required to dry out the material as
he works it to obtain adequate in place density of the soil.
When the percentage of moisture is known for a given sample, it is possible to compute the
“degree of compaction” as compared to a standard.
This is computed as follows:
(a) The wet density (Line 17) is divided by 1.00 plus the moisture in the sample expressed as
a decimal (Line 16). This yields the sample dry density.
(b) The sample dry density is divided by the standard dry density as established in the
proctor. This result multiplied by 100 expresses the degree of compaction in a
percentage.
1003.4 SIGNIFICANCE OF TESTS
The degree of compaction is a tool which monitors the shear resistance of the embankment due
to density. As previously stated, compaction depends on the character of the soil, moisture, and
compactive effort. The character of the soil cannot be changed, so moisture and compactive
effort must be regulated to obtain the required results. The specifications set forth the
compaction and moisture limitations for roadway embankments composed of soil when moisture
and density control is established for the project. These specifications also apply to projects
where no specific moisture or density control is established.
Several factors may affect the accuracy of the compaction test. These are as follows:
(a) Material being tested is not consistent in physical qualities with the material used to
establish the proctor curve. When this condition occurs, test results will be inordinately
in excess of 100 percent compaction, or increased compactive effort will produce little
change in the degree of compaction. A change in material will usually be accompanied
by a color, texture or visible granular size change in the material. A new proctor will
have to be run to establish new dry density and optimum moisture conditions.
243
Original Date: 1/3/94
Revised Date: 05/27/16
(b) Volume of test hole too small or false volume. It is imperative that the volume of the
sample hole to be at least .05 cubic foot. The intent is to test the compaction in the entire
lift of material placed, not just in the top layer which will receive the most compactive
effort. Compaction results in excess of 120 percent are possible when an inadequate
volume is tested.
False volumes in the sample hole are caused by testing being performed in unstable or
saturated subgrade areas. In these areas, the sides of the sample hole will sag inward
reducing the volume of the sample hole as compared to the weight of the material
removed. This will increase the compaction results. Also, it is possible to have tapered
sides in the sample hole or projections which impede the flow of the silica sand, thereby
reducing the volume.
(c) Rock particles in the soil. This is another deviation from the proctor as established for a
particular soil type. As the proctor is determined by using material which will pass a ¾
inch sieve, any large stone should be replaced in the sample hole. Small rock mixed in
the sample will increase the weight of the material removed from the sample hole,
increasing the density. In accordance with the specifications, material having more than
20 percent retained on a ¾ inch sieve is considered too rocky to be tested accurately.
Test results for the standard density test should range from a minimum of 85 percent for
uncompacted cut in natural ground to a maximum of 105 percent for aggregate or soil which has
had compactive effort applied in excess of that which will give the desired results.
1003.5 FREQUENCY OF TESTING
The “Schedule for Materials Sampling and Testing” specifies a frequency of testing of one test
per layer per 0.25 mile or 1,250 cubic yards for embankments and one test per cut per 500 feet.
On many of the projects the Resident Engineer will need several times this number of tests for
assurance of compliance. As this testing frequency represents a minimum number, the Resident
Engineer should satisfy himself as to testing required, being sure to thoroughly check for
compliance in compaction. Emphasis should be placed on very complete testing being
performed in the area around major structures and approach slabs.
The frequency of testing in aggregate bases should follow the above specified pattern with
consideration of quality control predominating minimum requirements. The minimum
requirements for density and thickness in aggregate bases will be one test per layer per 0.25 mile
and one test per 500 tons for moisture control.
1004 CONCRETE TESTING
The field testing of concrete is intended to provide the Resident Engineer with an on the spot
measure of the quality of the various classes of concrete being produced for inclusion in the
construction project. The field testing of concrete is in three phases – Slump Test, Air Content
Test and Compression Cylinder Test.
244
Original Date: 1/3/94
Revised Date: 05/27/16
The materials Engineer is responsible for providing the design mixes for the various classes of
concrete and the inspection personnel to inspect the proportioning and mixture of the concrete at
its source. The specifications provide the basic requirements for the production of concrete for
use on all projects.
1004.1 EQUIPMENT REQUIRED
The following equipment will be required to perform the concrete testing in accordance with
established procedures:
(a) Slump cone apparatus with testing surface (obtain at Materials Testing Laboratory).
(b) Flat strike off, tamping rod, rubber mallet, sugar scoop and 2 gallon or larger capacity
bucket (obtain at Materials Testing Laboratory).
(c) Air Content Meter (obtain at Materials Testing Laboratory).
(d) Compression Strength Cylinder Molds (obtain at Materials Testing Laboratory).
(e) Concrete Thermometer (obtain at Materials Testing Laboratory).
1004.2 SLUMP TEST
The slump test is a measure of the consistency of the concrete. The slump of a concrete sample
is expressed in inches and must not exceed the allowable limits expressed in the slump and
mixing water requirements of the specifications. Under no circumstance can the mixing water
requirement, as expressed in gallons/sack, enumerated in the above stated specification be
exceeded, regardless of slump. The Inspector should never advise the contractor on the amount
of water to use in the concrete mixture. It is the contractor’s responsibility to determine the
amount of mixing water required to produce a useable mix. If the contractor asks if he can add
water to the mix, he should be advised of the maximum permissible amount of mixing water
allowed and the limitations on the slump of the mix. Water may not be added to the mixture
more than twice. Each time water is added, the mixing drum should be revolved 30 times at the
proper mixing revolution rate.
The following link will take you to a video of a live slump test being performed and narrated
https://www.youtube.com/watch?v=EqKmtcF46lg
The following procedure should be followed to perform a slump test:
(a) The concrete must be sampled in accordance with AASHTO T-141-74. This procedure
requires sampling at three intervals during the discharge of concrete, except for central
or truck mixes. In this case, one sample may be taken after approximately 1 yard of
concrete has been discharged. This sample should be homogeneous and representative
of the entire mass. A large enough sample should be taken to provide for all three tests.
The sample should be placed directly on a clean, level, rigid, moistened surface with the
necessary testing performed as soon as possible. No further discharging of concrete
245
Original Date: 1/3/94
Revised Date: 05/27/16
should be allowed until testing is completed. This test should be performed after all
additional mixing water has been added.
(b) The slump test must conform to AASHTO T-119-74. The slump cone should be wetted
and placed on a rigid, level, moistened surface. The ears of the slump cone should be
stepped on and a steady pressure maintained during the test.
(c) The concrete for the test should be removed from the sample and placed in the slump
cone. The concrete is placed in 3 even layers (by volume – not by height) with 25
roddings from the tamping rod being distributed over each layer before the next layer is
placed. The rodding should be done evenly and should penetrate the entire layer being
consolidated and into the layer beneath. The cone should be overfilled in the last layer
and, after rodding, struck off flush with the top of the cone.
(d) Grasp the handles on the slump cone and step off the ears of the cone, being sure to
remove any loose concrete from around the base of the cone. With a steady vertical
motion, remove the slump cone (within 5 seconds + 2 seconds) (do not twist or move the
slump cone laterally) and place on the surface adjacent to the slump sample.
(e) Place the flat strike off atop the slump cone and measure the amount the sample has
slumped from the top strike off level of the slump cone to the top of the sample. The
distance from the strike off level of the slump cone to the displaced center of the sample is
the slump of the concrete and should be measured to the nearest 1/4 inch.
(f) Record the result on County Form C-50 (revised 3/8/91) “Data on Concrete Test
Specimens.”
(g) Dispose of the slump sample outside the form line and clean the equipment.
The slump test must be used to maintain a consistent concrete for the item being poured. The
contractor has the privilege of raising the slump toward the allowable maximum based on the
class of concrete. Any adjustment in mixing water should be noted on Form C-50, and the
material must be resampled to maintain the concrete within the specified parameters.
The slump test is an easy, quick and uncomplicated method for determining the consistency of
the concrete. Test results are adversely affected by improper tamping and by shifting of the
slump cone during the consolidation of the concrete sample in the cone. These two factors most
often produce a shearing or non-uniform slumping of the sample. An unleveled base upon which
the slump cone test is set will also produce a non-uniform slumping of the sample.
1004.3 AIR CONTENT TEST
The air content test is used to express the volumetric percentage of air in the concrete sample.
The concrete, as produced, will by nature contain 1.5 to 3.0 percent air by volume. For most
classes of concrete and for most construction applications, an admixture is added to the concrete
during the mixing procedure to chemically induce additional air in the concrete. A figure of
246
Original Date: 1/3/94
Revised Date: 05/27/16
6-1/2 percent air content has been established as optimum for ease of finishing and increased
serviceability of the concrete. A tolerance of + 1-1/2 percent has been deemed allowable for
variation from optimum.
The following link will take you to a video of a live air test being performed and narrated
https://www.youtube.com/watch?v=CfVaR79OgX8
The following procedure should be followed to perform an air content test;
(a) The sampling of the concrete should be done in accordance with AASHTO T-141-74 as
mentioned in the slump test.
(b) The Air Content Test must conform to AASHTO T-152-74. The air meter and all test
equipment should be wetted and a volume of water placed in the bucket for use in the
procedure. The air meter should be disassembled and the base placed on a rigid, level
surface.
(c) The concrete should be placed in the base from the sample taken previously in 3 equal
lifts and rodded 25 times per lift with the tamping rod as in the slump test. Each lift
should be consolidated by tapping the base with the rubber mallet (10 to 15 times). The
last lift of sample concrete should be overfilled and struck off with the flat edged strike
off. Care should be taken to strike off the final lift flush with the top of the base (plugging
of the petcock holes may occur if the base if overfilled – voiding the test). The strike off
concrete should be finished as smoothly as possible with no holes left in the finished
surface.
(d) The rim of the base should be hand-washed and cleaned of any sand or aggregate which
would interfere with a tight seal to the top of the apparatus. The top should be wetted
and wiped clean before placing on the base. The top of the apparatus is secured to the
base by 4 clamps attached to the top. It is important that these clamps be adjusted to the
length which will provide for a positive seal between the top and base to prevent the
escape of the compressed air used in the procedure. These clamps may be adjusted to
length by screwing the adjusting rod in or out as required to obtain a positive seal.
(e) The petcocks on the top of the apparatus should be opened and the syringe, which is
provided with the air meter, should be filled with water. The syringe should be used to
fill the petcocks by gently flowing the water into the petcock on one side until full and
then on the other side until a reverse flow of water is noted. (It is necessary to fill the
slight void and both petcocks in the top of the apparatus completely with water for an
accurate test).
(f) The air percentage gauge should be pumped to the initial setting located in the lower
right portion of the meter. To do this, the air release valve must be closed. This valve is
located atop the air meter on the air compression cylinder next to the air pump. The
initial pressure setting should have been predetermined by a calibration performed at the
247
Original Date: 1/3/94
Revised Date: 05/27/16
Materials Testing Laboratory. The gauge should be tapped after pumping is completed
to ensure sticking of the needle has not occurred.
(g) The petcocks should be refilled and closed, the initial setting of the gauge checked and
then the pressure should be released by firmly pushing down on the pressure release
handle next to the air release valve. The needle should move from the setting to a point
which will indicate the percentage of air in the concrete. The gauge should again be
lightly tapped and the air content reading recorded on the same form as the slump
reading.
(h) Open the petcock opposite your position to release the air pressure in the base and
disassemble apparatus. Open air release valve until needle in gauge reaches hand free
position. Dump concrete sample outside form line and clean equipment completely. Do
not use this sample in the concrete pour.
The reading obtained in this test is an indication of the volume of air in the concrete sample.
From this result, a correction for the porosity of the aggregate must be made. This correction
factor is normally computed at 0.25 percent and should be subtracted from the reading to obtain
the corrected figure.
The accuracy of the air content test is primarily dependent on the mechanical integrity of the
testing equipment. In order for an accurate test to be completed, a positive seal must be present
at the interface between the top and base. Failure to obtain a positive seal presents the greatest
chance of error due to pressure loss.
When the results of the air content test indicate a percentage of air below the acceptable level, it
is possible to increase the air content by the addition of water and the rotation of the concrete
mixing drum, provided the slump will allow the addition of the water and the maximum number
of mixing revolutions is not exceeded. When the test results show the air content to be in excess
of the allowable, the concrete should be rejected.
Several factors affect the air content of the concrete after batching. These are:
(a)
(b)
(c)
(d)
Improper transportation and mixing equipment.
Length of haul and rough road conditions.
Various admixtures and hot mixing water.
Concrete aggregate gradation and cement content.
Each can have a detrimental effect on the air content of the concrete and should be considered as
potential problem areas should a problem arise.
1004.4 COMPRESSION CYLINDER TEST
The compression cylinder test provides the Resident Engineer with a means of measuring the
strength of the concrete placed on the project. The compression strength developed in the
248
Original Date: 1/3/94
Revised Date: 05/27/16
concrete is one of the key considerations in the development of the design mix and provides an
indication of the quality and life span that can be expected from the various concrete items.
Compression strength is also used as a guide for the backfilling, removal of false work and
opening of structures and roadways to traffic.
The following procedure should be used when preparing compression cylinders in the field:
(a) The concrete should be taken for sampling in accordance with AASHTO T-141-74 as
with the slump and air content test.
(b) The compression cylinders must be cast and cured in accordance with ASTM Method
C31. The compression cylinders should be cast from concrete which has also been
sampled for slump and air content. A set of 4 or 6 cylinders will be cast at any time using
the molds provided by the Materials Engineer which meet ASTM C470 conditions.
(c) The cylinders should be placed on a rigid level surface, preferably in the shade, and in a
position where they will remain unmoved for 24 hours. It is important that the cylinders,
once cast, be maintained at a temperature between 60° F and 80° F.
(d) The concrete cast in the compression cylinders should be placed in 3 even lifts with 25
strokes from the tamping rod distributed evenly over each layer as in the air content test.
The sides of the cylinder mold should be tapped with the rubber mallet. The final layer in
the cylinder mold should be slightly overfilled and struck off even with the top of the mold
and finished as smoothly as possible.
(e) The cylinder mold should be covered with a plastic bag or cap provided by the Materials
Engineer. This covering should be made as soon as possible. (Note: Should it be
necessary to relocate the molded cylinders, it should be done while the concrete is still in
a plastic state; this should be avoided if possible.)
(f) The cylinder should not be moved for 24 hours, but shall be transported to the laboratory
as soon as possible thereafter. If it is inconvenient to transport the aged cylinders to the
Materials Testing Laboratory, they should be stored in wet sand, completely covered,
until they can be transported. When transported, the cylinders should be laid flat and
protected from rolling or bumping. The Resident Engineer should note any deviation in
the storage or transport of the cylinders on Form C-50.
(g) Form C-50 must be presented with the cylinders at the Materials Testing Laboratory. In
addition to the slump and air content previously recorded on the form, it will also be
necessary to record the gallons of water added, weather conditions, ambient
temperature, concrete temperature and the general information required at the top of the
form. This same information should be recorded in the Materials Testing Book and the
test report coded for ease of reference when 7 day and 28 day cylinder compression
strength is checked.
249
Original Date: 1/3/94
Revised Date: 05/27/16
The compression cylinders are an indicator of the strength of the in place concrete. The
permanency of the structure or roadway will depend in large part on the compression strength of
the concrete. Care should be taken in the preparation of the cylinder. Care should also be taken
not to move the cylinders in the first 24 hour period. Disturbed cylinders should be discarded
and so noted on Form C-50. Care should be taken in transportation of the cylinders to prevent
fracturing by dropping or hitting. These factors may be the cause of low and erratic compression
strength results.
1004.5 SIGNIFICANCE OF TESTS
The purpose of these concrete tests is to provide for a uniform, consistent product. The
information obtained from these on-site tests will allow for adjustments at the point of
production, which should provide a uniformly homogeneous product with uniform
characteristics within the allowable parameters. Materials which do not meet the parameters set
forth in the specifications for cement, slump, mixing water and air content should be rejected.
Concrete that exceeds the time limit from batching to final discharge or a temperature of greater
than 90° F when placed in a bridge deck should be rejected.
The Materials Engineer should be notified of these rejections, as should your immediate
supervisor. The results of all materials testing should be recorded in the Materials Testing Book,
and the plant materials inspector should be kept informed as to results and the need for
alterations in the concrete mix. The ticket should be signed and marked “Rejected” – “No Pay”
with the reason for rejecting the material noted. A copy of the ticket should be retained for your
records.
1004.6 FREQUENCY OF TESTING
The three phases of concrete testing are for only one purpose – to provide a consistent workable
concrete. With this in mind, the testing should be conducted at whatever frequency is necessary
to establish and maintain this objective.
The “Schedule for Materials Sampling and Testing” provides for minimum testing requirements
only. Portland cement concretes are to be rested at a minimum frequency of one test per 250
cubic yards or one per day (slump, air content and compression cylinders). Structural concretes
are to be tested at a frequency of one test per 100 cubic yards or one per day.
In the course of obtaining a consistent, workable concrete product, a full complement of tests
may not be required each time. Slump and air content tests should be used as required to
determine results and interpret the effect of adjustments to the design mix. When a consistent,
workable product is produced, the complete compliment of tests (slump, air content and
compression cylinders) should be taken for a representative sample.
1005 COUNTY LABORATORY SOILS TESTING
250
Original Date: 1/3/94
Revised Date: 05/27/16
The Materials Testing Laboratory provides testing of construction materials to be utilized in the
various segments of the project. A number of these test procedures are conducted on a periodic
bases as required in the “Minimum Field Schedule for Materials Sampling and Testing” or by the
specifications. The specifications require testing of materials and establish parameters of
acceptability for their use. The purpose of this testing is to provide the Resident Engineer with
the assurance that the quality of the materials used on the project which he cannot test on site is
within the required parameters and is acceptable. As many of these tests must be run for several
projects and require adherence to an established procedure, ample time must be allowed for
results to be obtained. Testing of construction materials will be done utilizing ASTM or
AASHTO procedures.
The Materials Engineer should be contacted when a specific or non-standard test is being
performed. In general, the Materials Engineer will perform all needed laboratory testing without
specific notice being given to the Resident Engineer. The results of these tests will be forwarded
to the Resident Engineer or may be acquired at the Materials Testing Laboratory. Where
samples of materials for testing are to be taken in the field, the Resident Engineer should arrange
for sample containers, sampling and delivery to the Materials Testing Laboratory for completion
of the testing.
The following is a list of tests performed at the Materials Testing Laboratory.
1005.1 ATTERBERG LIMITS
The Atterberg Limits are the moisture content of a soil at points where the soil’s physical
properties transform from one state to another. They are individually defined as follows:
(a) Shrinkage Limit – The shrinkage limit test is performed in accordance with AASHTO TT-92-70 and delineates the semi-solid from the solid state. Values of this test will range
from 6 to 14 for clay soils and from 15 to 30 for silty soils. This test is not normally
performed unless specifically requested.
(b) Plastic Limit – The plastic limit test is performed in accordance with AASHTO T-90-70
and represents the moisture content at which a soil changes from the semi-solid to the
plastic state. The plastic limits of silts and clays will range from 5 to 30 and will not vary
widely. Normally, the more silty soils will have the lowest plastic limits.
(c) Liquid Limit - The liquid limit test is performed in accordance with AASHTO T-89-76
and represents the moisture content at which a soil changes from the plastic to the liquid
state. Generally, soils with high liquid limit values are clays with poor engineering
properties. The normal limits for clay soils will range from 40 to 60, with heavy clays
ranging up to 85. For silty soils, the normal values will range from 25 to 50, with sandy
soil producing no result or a non-plastic condition.
The plasticity index is the difference between the liquid limit and the plastic limit and represents
the range of moisture content over which a material is in the plastic state. The higher the plastic
251
Original Date: 1/3/94
Revised Date: 05/27/16
index, the more likely the material is to be a clay; the lower the plastic index, a silt. The normal
range of clay soils will yield a plastic index of 20 to 40, while the normal range of silt soils will
range from 10 to 20.
The liquid limit and plastic index of a soil will provide an evaluation of its quality for
construction applications. For quality considerations, the greatest soil stability will appear in
soils with a liquid limit of 25 or less and a plastic index with a maximum of no more than 6
(basically, a granular material) which is normally not available for embankment construction in
this area.
The St. Louis area has two basic soil types – a clay, which will have a liquid limit ranging from
35 to 85 and a plastic index ranging from 15 to 55, and alluvial or loessial silt having a liquid
limit ranging from 25 to 45 and a plastic index in the range of 5 to 30. These two soil types will
be stable within a narrow range of moisture. It will be necessary to closely monitor soil moisture
and control that moisture content in order to maintain stability in the embankment. The
specifications provide limitations for moisture content and methods of compaction necessary to
provide the desired embankment stability.
1005.2 MOISTURE-DENSITY RELATION (PROCTOR TEST)
The moisture – density test or proctor test must be conducted in accordance with AASHTO T-99
procedures for the standard moisture – density test or AASHTO T180 procedures for the
modified moisture – density test. The specifications are based on relationships derived from the
Standard Proctor Test.
The purpose of the moisture – density test is to provide the Resident Engineer with a means of
compacting a material so as to obtain the highest shear resistance by obtaining the maximum
density. The test is designed to obtain the best results from the soil available. The point at
which the maximum density is obtained is partially governed by a moisture content in the soil
which best acts to lubricate and consolidate individual soil particles; this moisture content is
termed “optimum” and provides a narrow range of values for maximum density and soil
stability. This information is illustrated on the graph which accompanies the soil test
information. The compactive effort provided by the compaction equipment is the remaining
variable factor in obtaining the maximum density of an embankment. The standard moisturedensity test is based on the assumed average compactive effort available with the more common
types of compaction equipment. When greater compactive effort is applied, the compaction may
range beyond the standard maximum density figure. This possibility is the basis of the modified
moisture – density test which assumes a higher compactive effort being applied to the
embankment.
The following range of values may be anticipated for the standard moisture – density test:
252
Original Date: 1/3/94
Revised Date: 05/27/16
TABLE 1005.2 – STANDARD RANGES FOR MOISTURE – DENSITY TEST
(AASHTO T-99)
Clays:
Maximum Density
90 – 105 Pounds per Cubic Foot
Optimum Moisture
20 – 30 Percent
Silty Clays:
Maximum Density
Optimum Moisture
100 – 115 Pounds per Cubic Foot
15-25 Percent
Sandy Clays:
Maximum Density
Optimum Moisture
100 – 135 Pounds per Cubic Foot
8 – 15 Percent
Silts:
Maximum Density
Optimum Moisture
98 – 110 Pounds per Cubic Foot
11 – 17 Percent
The expected results for the modified moisture – density test will range from 5 to 10 pounds per
cubic foot higher for maximum standard density and 3 to 10 percent lower in optimum moisture
content. Generally speaking, soil compacted to 95 percent of a Standard Proctor will
approximate the same in place density of soil compacted to 90 percent of a modified proctor.
1005.3 FREQUENCY OF TESTING
Generally, the liquid limit and plastic limit tests are conducted as a standard battery of
procedures for each sample of soil presented for determination by the Resident Engineer. One
such set of tests should be executed for each classification of soil type per roadway cut or
embankments, including any borrow excavation. This requirement provides the Resident
Engineer with a degree of responsibility in the establishment of differing soil strata for testing.
The shrinkage test is conducted only as requested by the Resident Engineer.
The moisture – density test is conducted as a standard part of the battery of testing performed on
soil samples presented for classification and at the same frequency as other Atterberg Limits
Tests.
When, throughout the course of the embankment placing operation, it becomes apparent that the
physical properties of the borrow material have changed, the Materials Testing Laboratory
should be notified.
1006 COUNTY LABORATORY AGGREGATE TESTING
1006.1 ATTERBERG LIMITS
The liquid limits test and plastic index test are conducted on that portion of the aggregate bases
which will pass the No. 40 sieve. From these results, the plastic index may be computed with the
following limits established in the specifications:
253
Original Date: 1/3/94
Revised Date: 05/27/16
TABLE 1006.1 – STANDARD ATTERBERG LIMITS VALUES
Type 1 Aggregate for Base:
Plastic Index – 0 to 6
Type 2 Aggregate for Base,
Chat or crushed stone:
Plastic Index – 0 to 6
Sand and Gravel:
Plastic Index – 0 to 6
Type 3 Aggregate for Base:
Plastic Index – 0 to 8
Sandstone, Sand or Sand Gravel:
Plastic Index – 2 to 8
1006.2 MOISTURE – DENSITY RELATION
The moisture – density test is conducted for aggregate base courses as for soils so that
compaction may be obtained as the specifications require.
The following range of values may be anticipated for aggregate base courses produced in the St.
Louis area:
TABLE 1006.2 – ANTICIPATED AGGREGATE BASE MOISTURE – DENSITY
RESULTS
Type 1 Aggregate:
Maximum Density
Optimum Moisture
125 Pounds to 140 Pounds per Cubic Foot
7 Percent to 14 Percent
Type 3 Aggregate:
Maximum Density
Optimum Moisture
130 to 138 Pounds per Cubic Foot
9 Percent to 14 Percent
Type 2 and 4 Aggregate for base are very infrequently used as are Portland cement
treated bases.
In the event these bases were to be used, the proper testing would be performed to
establish the Atterberg Limits and moisture – density relations.
1006.3 GRADATION TESTS
254
Original Date: 1/3/94
Revised Date: 05/27/16
The determination of gradation by sieve analysis is performed in accordance with AASHTO T27. The sieve analysis requirements for aggregate bases (Types 1-4) are specified in the
specifications.
1006.4 FREQUENCY OF TESTING
The Atterberg Limits Tests are made on a basis of one per material supplier. This determination
for the plasticity index is made for that part of the aggregate sample passing the No. 40 sieve.
The moisture – density relationship is also made at a frequency of one per source. The gradation
test is made at a frequency of one per 5,000 tons at the Materials Testing Laboratory and at a
frequency of one per 500 tons at the plant site by a Materials Inspector. These test results are
reported on Form C-91 and are presented to the Resident Engineer for his review.
1007 COUNTY LABORATORY BITUMINOUS MATERIALS TESTING
A large number of test procedures are performed on the bituminous and aggregate components of
asphaltic concrete and the various bituminous products used in the construction process. These
tests are performed at the point of manufacture of the asphaltic concrete and from samples taken
in the field by Materials and Construction inspection personnel. These tests are to provide
quality assurance for the materials used and to indicate the serviceability of the project as
constructed. The majority of these tests are confined to the laboratory; however, density
determinations of the constructed bituminous pavement will be made from samples which are
taken in the field.
1007.1 DENSITY DETERMINATIONS
The determination of density of bituminous pavement in the field is made from nuclear density
testing procedures or from test cores which have been extracted in the field. Cores taken for
density tests will be drilled prior to allowing vehicular traffic to travel over those sections, or as
soon thereafter as practicable.
1007.2 FREQUENCY OF TEST
The parameters of accuracy should be checked when evaluating results by these two methods.
When thickness and density are checked by cored samples taken on the project, the AASHTO T168 procedure is followed to obtain the necessary test samples. Four cores will constitute a
sample. Thickness and density will be determined by AASHTO T-230 procedures and will be
reported on County Form C-20. Laboratory determined density and thickness will take
precedence over field results. If only cores are used for mat and joint density determination, a
set of cores (4 mat and 2 per unconfined joint, if applicable are required every 2000 lane feet. At
least on e set of cores samples will be taken for each day’s production. If nuclear guage readings
are used for mat and joint densities, a set of cores will be required for correlation each day for
each mixture used. When a nuclear density guage is used, no less than one set of nuclear
readings(12 mat and 2 per unconfined joint) every 1,000 feet or fraction therof per day of paving
shall be taken.
255
Original Date: 1/3/94
Revised Date: 05/27/16
1008 COUNTY LABORATORY LIQUID ASPHALT TESTING
The testing of liquid asphalt (cutbacks) for prime coat is to establish a quality assurance for
material to be used on the project. The specified range of acceptability for each type of liquid
asphalt is stated in the specifications. These materials will be sampled on the project and at the
storage site by both Construction and Materials inspection personnel.
Samples taken in the field will follow AASHTO T-40 procedures which stipulate the following
procedure:
(a) The minimum sample per test is 1 quart.
(b) The sample container must be an approved type capable of being securely sealed and
free of moisture or rust. Test sample containers are available at the Materials Testing
Laboratory.
(c) For samples taken from a distributor truck, the sample valve should be opened and 1
gallon of material is allowed to discharge before a sample is drawn.
(d) The sample should be caught in the sample can and sealed immediately to avoid any
contamination. (Caution: Materials may be extremely hot and may splatter onto skin or
clothing).
(e) The sample should be labeled and dated. The sample should be forwarded to the
Materials Testing Laboratory for testing and evaluation.
1008.1 EMULSIFIED ASPHALTS
Emulsified asphalts are to be tested in accordance with AASHTO T-59 procedures from samples
taken in accordance with AASHTO T-40 procedures as previously outlined. The various
requirements for quality and purity are contained in AASHTO-140-70 or AASHTO-208-72
procedures as specified in the specifications.
1008.2 FREQUENCY OF TESTING
The testing of liquid asphalts and emulsified asphalts will be performed at a frequency of one test
per source. The samples should be obtained as soon as possible in advance of placing for testing
at the Materials Testing Laboratory.
1009 PORTLAND CEMENT CONCRETE INSPECTION
Portland cement concrete is tested at the point of manufacture, whether at a central plant or an
on-site batch plant, by representatives of the Materials Testing Laboratory. The purpose of this
testing is to provide a consistent, workable product to be used in the construction process. The
256
Original Date: 1/3/94
Revised Date: 05/27/16
various tests are to provide the necessary component control to produce a mixture which will
conform to the design mix established by the Materials Engineer for the various classes of
concrete. The specifications provide the general parameters, allowable variations and procedure
for production of the concrete as designed. As a strict adherence to the mix design is critical to
the quality of concrete, a number of test procedures are performed at the point of manufacture.
1009.1 SAMPLING BY RESIDENT ENGINEER AND MATERIALS PERSONNEL
The sampling of concrete for testing will be performed in accordance with AASHTO T-141
procedures. This is the procedure utilized by construction personnel for field testing. Concrete
samples thus taken are tested for slump and air content. Compression cylinders are also molded
and sent to the Materials Testing Laboratory for evaluation. These concrete tests are made in
accordance with the same procedures outlined in Section 1004 of this manual, and test results are
comparable between plant and field. Test results will be shown on Form C-50, copies of which
will be forwarded to the Resident Engineer. Material tests made at the point of manufacture not
only represent a check on strength and consistency of the concrete produced, but provide the
Materials Inspector with a means of monitoring the mix design provided by the Materials
Engineer. Based on these results, the Materials Inspector may modify the water and airentrainment additives to produce a product within the desired parameters of the specifications
and the economy and workability requested by the contractor. It should be stated that even
though the concrete is regularly tested at the point of manufacture, the test results obtained in the
field take precedence over the plant results. Rejection of materials composing the concrete
mixture will be made by the Plant Inspector, but rejection of the concrete mixture will be made
by the Resident Engineer. For this reason, good communication must be maintained between the
Plant Inspector and the Resident Engineer.
1009.2 GRADATION CONTROL AND SIEVE ANALYSIS
Gradation control of both the coarse and fine aggregates is necessary to ensure the required
strength, durability and workability for each class of concrete produced. The specific gradation
test, by class of aggregate, is performed in accordance with AASHTO T-27 and T-11 procedures
and is reported on County Form C-91, copies of which will be forwarded to the Resident
Engineer. The stipulated gradations for both coarse and fine aggregates are contained in the
specifications. Requirements for the furnishing of samples of aggregate by the contractor for
evaluation are contained in the specifications.
A wet sieve analysis, which discloses the amount of material passing the 200 sieve, is often
conducted in conjunction with the gradation test. This test procedure is designed to show the
amount of dust present in the aggregate sample. As the dust is considered a contaminating agent,
the amount is limited by the specifications.
1009.3 MOISTURE CONTROL OF AGGREGATE
The moisture content present in the aggregate must be evaluated in order to maintain the proper
water – cement ratio. This evaluation is performed in accordance with the provisions of ASTM
257
Original Date: 1/3/94
Revised Date: 05/27/16
C566 procedures. The results obtained from this procedure are recorded on Form C-80, together
with the moisture correction to be applied to the mixture.
1009.4 YIELD TESTS
Occasionally, the plant inspector will be requested to perform a yield test to determine the
volume of concrete being produced by a particular mix design. This test is conducted in
accordance with AASHTO T-121 procedures. All concrete mix designs currently in use are
designed to produce a yield of 27.0 cubic feet.
1009.5 FREQUENCY OF TESTING
The Materials Inspector at the plant will perform a large number of tests in obtaining and
maintaining a consistent concrete mixture. The tests shown on the “Schedule for Materials
Sampling and Testing” are a minimum and do not reflect the testing performed at the point of
manufacture. As a minimum, slump, air content and compression cylinder tests are made at a
frequency of one test per 250 cubic yards for pavement concrete and at a frequency of one test
per 100 cubic yards, or one per day, for most other classes of concrete.
The determination of moisture content in the coarse and fine aggregate is made at a frequency of
one test per day, or as required, based upon observation of the aggregate. The yield
determination will be made only when requested to establish the amount of mix being produced
per batch.
In addition to testing performed at the point of manufacture, certain tests are conducted on the
cement and aggregate components of the concrete mixture at the Materials Testing Laboratory.
These testing procedures are conducted on samples furnished by the contractor and represent
materials currently in use at the plant.
1010 INSPECTION OF DRAINAGE ITEMS
1010.1 BRICK TESTING
The Materials Testing Laboratory will perform a number of test procedures on brick used to
construct inlets and manholes on the project. These bricks will be of a type distinguished as
grades MM or SM and meeting the requirements of ASTM C32-66. These bricks will be
composed of clay or shale and will be tested in accordance with the procedure set forth in ASTM
C67-66. Sampling will be representative, individual bricks selected at a rate of 10 bricks per
50,000 bricks used, or fraction thereof. The bricks will be tested for compression strength by
cutting square samples from the brick, capping each and applying a compression load until
fracturing occurs. Five specimens will be tested, and the averaged compression strength will be
reported on Form C-66.
1010.2 FREQUENCY OF TESTING BRICK
258
Original Date: 1/3/94
Revised Date: 05/27/16
The frequency of testing for the stipulated tests on clay or shale bricks will be performed at a rate
of one test per 50,000 bricks used. The testing of concrete and masonry bricks will be performed
at a rate of one test per 10,000 bricks used.
1010.3 TESTING OF A PIPE
The testing performed on pipe at the plant is performed by the manufacturer and is randomly
observed by Materials Inspection personnel as a check on production methods and for
acceptance of manufactured lots of material. Representative samples are taken for testing, which
is performed in accordance with AASHTO T-33-72 procedures.
The specifications provide criteria for manufacture, inspection, rejection and required testing and
certification frequency for the various types and classes of pipe and tile. As there are several
varieties of pipe enumerated, many of the checking procedures rely on visual inspection to
confirm the manufacturer’s certifications and guarantees. The Resident Engineer or his
designee, along with representatives from MSD, will inspect the pipe after it arrives on the
project.
It should be noted that at times pipe becomes cracked due to errant handling on the project after
it has been inspected. The Resident Engineer is charged with the final inspection of all pipe and
has the authority to reject pipe sections that are not in conformance with the specifications.
Under no circumstances should uninspected pipe be placed for construction until it is inspected.
1011 TESTING METAL PRODUCTS AND MISCELLANEOUS ITEMS
1011.1 SURFACE COATINGS
Various metal products are used in the construction process which has been coated for protection
from chemical effects or from weathering. This coating is tested independently for chemical
content and amount of coating applied. Personnel of the Materials Testing Laboratory will
perform testing to confirm specified coating thickness in accordance with ASTM E376 and A219
procedures. Testing will be performed on corrugated metal pipe, structural steel pipe arches,
plate pipe arches, guard rail, guard cable, guard fence and any painted surface as required by the
specifications.
In addition to the above methods, a visual inspection on site should be made by the Resident
Engineer. This inspection should disclose holes, voids, spalled areas, contaminated or cracked
areas and scratched or otherwise damaged coatings. When epoxy coated reinforcing steel is to
be utilized in the construction, a field continuity test will be made before the deck is poured and
after the deck is in place. Testing will be performed in conformity with the specifications.
1012 REINFORCING STEEL
259
Original Date: 1/3/94
Revised Date: 05/27/16
Reinforcing steel will be tested in accordance with ASTM A615 procedures. Both Grade 40 and
Grade 60 reinforcing steel will be inspected and sampled. Samples for testing will be obtained
by the Materials Inspector at the site, or by the Resident Engineer at the project, when delivered
for use. The testing of the samples will be performed by the Materials Testing Laboratory.
Samples shall be cut to lengths of 36 inches and accompanied by Heat No., Plant Supplier,
Project Name, Number and Date Received.
1013 PRESTRESSED CONCRETE BEAM INSPECTION
Personnel of the Materials Testing Laboratory will observe and inspect the fabrication of the
prestressed concrete members at the point of manufacture. Testing and sampling will be
conducted at the site of manufacture in accordance with ASTM and AASHTO Specifications.
Concrete testing of air content, slump and compression strength will be made, as will quality
assurance testing of steel wire and plates. At least two weeks advance notice must be given prior
to the intended fabrication date so that the inspector’s travel arrangements can be made.
1014 STRUCTURAL STEEL INSPECTION
The fabrication of structural steel items will be randomly monitored by personnel of the
Materials Testing Laboratory. Samples will be provided by the fabricator for independent
analysis in combination with certifications and chemical analysis as provided by the fabricator.
1015 CERTIFICATION REQUIREMENTS
All material to be used in the construction of the project must be certified as complying with the
parameters of testing as required by the specifications. The testing parameters have been
standardized and are indicated in the specifications. Testing of the material on site, at the point
of manufacture or by independent testing facility does not preclude the need for a Certification of
Compliance.
The following information should be included in any Certification of Compliance:
(a) A letter of transmittal on the letterhead stationary of the supplier directed to the
contractor or this Department conveying the certification with any attached reports or
information concerning proper utilization or implementation of the material.
(b) A job designation is required for each certification for each project. Blanket
certifications or copies of certifications from other projects are unacceptable.
(c) A statement of factual compliance is mandatory. Each certification must represent the
material as complying with the proper testing procedure (ASTM, AASHTO, and ANSI)
criteria. To support this claim, brand names, component part names, identification
numbers, heat numbers or any other pertinent information should be stated.
260
Original Date: 1/3/94
Revised Date: 05/27/16
(d) Attachments of reports which prove the quality of the material to be used on the project
may also be included. These reports will include bills of material, certified metallurgical
tests, certified chemical analyses and physical properties tests, tests performed by
independent testing laboratories and governmental agencies and mill and heat tests.
(e) The signature of an authorized agent of the manufacturer, accompanied by the statement
and signature of a notary public, acknowledging the authorizing signature. This
certifying procedure by signature should also be included on all certified mill tests,
chemical analyses and physical properties tests.
In the event of materials used in the construction project are from a larger stock of material
maintained by the contractor for his use, the contractor may provide a Certification of
Compliance on his own. The same general format should be followed, and the material will be
subject to testing and rejection as if provided by an independent supplier. A schedule which
notes the more common construction materials requiring certification is included in Table
1017D.
No certifications will be required for most salvaged materials which are allowed by Special
Provision to be reused on the project. Testing as to the quality of salvaged material may also be
waived by Special Provision. Generally, only salvaged asphalt will be extensively tested before
reuse.
1016 RECORD TESTING
Record Testing will be performed by members of the Materials Laboratory to provide a double
check on field and plant testing performed by Construction and Materials personnel. On projects
which are partially or totally federally funded, Record Testing will be performed to provide
assurance of compliance with required testing procedures and testing parameters. In point of
fact, the Record Test acts as a certification of testing accuracy and mix proportioning as used on
the project. Record Tests for Federal Aid Projects are often performed in the presence of
MoDOT inspectors.
On projects which receive federal funds, the Resident Engineer should coordinate record testing
requirements with the Materials Engineer. Ample notification should be given to the Materials
Engineer of record testing needed. The Materials Engineer will provide a copy of the completed
Records Test (so specified on the report) for the Project Records.
Record testing performed on the project should be observed either by the Resident Engineer or
Inspector in charge of testing so that uniformity of procedure may be ascertained. Any variation
in technique should be resolved so that all testing procedures are performed uniformly.
The results from record testing will supersede results obtained by field personnel. A schedule of
minimum record testing requirements for Federal Aid Projects is located at the end of this
chapter in Table 1017C.
261
Original Date: 1/3/94
Revised Date: 05/27/16
1017 SMALL QUANTITY ACCEPTANCE
This section will apply only to those projects which are totally or partially funded by Federal
monies,
Under normal circumstances, on any project in St. Louis County, material to be incorporated into
the project will be inspected at the point of manufacture and certified by the necessary testing
procedures by a Materials Inspector. The signature of the Materials Inspector will serve to
confirm the quality and acceptability of the material for use in the project.
On federally funded projects, provisions have been made to allow the Resident Engineer to
accept certain materials in small quantities without the normal inspection and certification
requirements. This acceptance is to be used to simplify the paperwork on the project and reduce
the sampling and testing requirements for small quantities of material to be used on the project.
The main consideration in implementing this procedure is its application to those materials
which will not adversely affect the traffic carrying capacity of the completed project or to
concrete for use in major structures, permanent main line, ramp improvements or other structural
items.
Concrete items to be accepted as small quantities are accepted assuming that occasional testing
for air, slump and compressive strength will be performed. In most cases, the testing
requirements as set forth in Section 1004 will supersede any reduction in testing. When small
quantity concrete is acceptable, the delivery ticket should contain the class of concrete, cement,
aggregate, water weights and time of batching.
When any material is allowed on a small quantity basis, a running record of the amount used to
date should be kept. Under no circumstance should the daily or project total amounts be
exceeded, nor should the use of small quantities become a common place procedure.
TABLE 1017A – SMALL QUANTITY ACCEPTANCE
ACCEPTABLE
ACCEPTABLE
AMOUNT PER DAY
AMOUNT PER PROJECT
MATERIAL
REMARKS
CONCRETE1, 2
Sidewalk
500 S.Y.
Curb & Gutter
500 L.F.
Base Course or Widening
500 S.Y.
Pavement Patching and
Temporary Pavement
No Limit
262
Original Date: 1/3/94
Revised Date: 05/27/16
Building Floors or
Foundations
Slope Paving and Headers
Paved Ditch
Guardrail Anchorage
Metal Pile Shells
Small Culvert Headwalls
Fence Posts
Drainage Inlets, Manhole
Floors & Catch Basins
Sign, Signal and Light Bases
Grout for Pipe Fill
OTHER MATERIALS2
100 Tons
500 Tons
When
Weight
Accepted
by
Aggregates
50 Tons
250 Tons
When
Weight
Accepted
by
Bituminous Mixture
Bituminous Material
100 Gal.
Paint
20 Gal.
Accepted by weight and
Analysis on container
label
Any amount; recognized
commercial grades only
may be used.
Lumber
Masonry
100 Pieces
Concrete Pipe
100 L.F.
Clay Pipe
100 L.F.
Nominal Size and Visual
Inspection
NOTES:
1
Concrete must conform to St. Louis County or MSD Specifications for the Class of concrete required
2
These quantities do not apply to temporary pavement or other items which will be maintained and
removed by the Contractor before the end of Project.
263
Original Date: 1/3/94
Revised Date: 05/27/16
In addition to these requirements, a visual inspection and verification of apparent weight will be
required on those materials accepted on the basis of weight. The weight should be clearly
marked on the material ticket, and for those materials originating in St. Louis County, the weight
should be certified by a contractor’s representative who has taken an “Oath of Weighmaster.”
This small quantity acceptance procedure is predicated on one of the following methods:
(a) Acceptance may be made on the basis of visual inspection by the Resident Engineer,
provided the source has been previously approved by the Materials Engineer and is
currently producing acceptable material. The material ticket should be noted by the
Resident Engineer as being accepted on the basis of visual inspection and the quantity so
accepted noted in the Daily Diary.
(b) Acceptance may also be made on the basis of a certification by the producer or supplier
which states that the material complies with the appropriate provisions of the
specifications. This certification must accompany the product as delivered and may
appear on the material ticket. Failure to provide this certification is cause for reflection
of the product. Acceptance by this method must also be noted in the Daily Diary together
with the quantity accepted.
TABLE 1017B – MINIMUM FIELD SCHEDULE FOR MATERIALS SAMPLING AND
TESTING
MATERIAL
Section 203
Placement of
Embankment
≤ 18” below
top of
subgrade to
top of
subgrade
PROPERTY / QUALITY
FREQUENCY
Soil Proctor, P.I.
Before placement, Project Inspector
to sample with Materials Lab. One
per source, unless there is an
obvious change in the material.
Testing performed by Soils Lab.
Moisture / Density test
Surface Tolerance
> 18” from
top of
subgrade
Soil Proctor, P.I.
A minimum of one set of two
nuclear density tests or one Sand
Cone per day per source for each
active grading spread (lift) by
Project Inspector. For finish
subgrade, a minimum of four
density tests per day per source for
every 4,000 s.y.
Finish subgrade to ± 1/2 in.; three
checks per 2-lane width per 1/2
Station (50 ft) by Project Inspector.
Before placement, Project Inspector
to sample with Materials Lab. One
per source, unless there is an
obvious change in the material.
Testing performed by Soils Lab.
FORM
S-1,
S-2
C-20,
C-96,
C-97
Field
Book
S-1,
S-2
264
Original Date: 1/3/94
Revised Date: 05/27/16
MATERIAL
PROPERTY / QUALITY
Moisture / Density test
Sieve Analysis
P.I., MDR ( Proctor)
FREQUENCY
A minimum of one set of two
nuclear density tests or one Sand
Cone per day per source for each
active grading spread (lift) by
Project Inspector.
One per day of production from
approved stockpile or job site by
Materials Quarry Inspector.
Before placement or compaction,
Materials Field Inspector to sample
one per source, unless there is an
obvious change in the material.
Testing performed by Soils Lab.
No quarry inspector signature on
delivery ticket required when paid
for by unit area.
FORM
C-20,
C-96,
C-97
C-1005
C-1007
S-1,
S-2
Section 304
Placement of Aggregate Base
(Type 1 or 5)
Moisture/Density
Surface
Tolerance
Section 502
Portland Cement Concrete
Pavement
A minimum of one set of two
nuclear density tests or one Sand
Cone per day per source per 4,000
s.y. (1,000 tons) of material laid.
Testing by Project Inspector
Under
Concrete
Pavement,
Approaches or
Sidewalk
0 to +1/2 in.; four checks per 2-lane
width per 1 /2 Station (50 ft).
Testing by Project Inspector.
Under
Bituminous or
Asphaltic
Pavement
± 1/2 in.; three checks per 2-lane
width per 1/2 Station (50 ft).
Testing by Project Inspector.
Air Content, Temperature
and Slump
Air, Temperature and Slump tests
are to be made at the beginning of
each pour, for each class of concrete
and supplier, and for every 100 c.y.,
thereafter. Plant inspector to sign
first and final load delivery ticket or
when significant changes are made.
Testing by Project and Plant
Inspectors.
C-20,
C-96,
C-97
Field
Book
Field
Book
L-99
265
Original Date: 1/3/94
Revised Date: 05/27/16
MATERIAL
PROPERTY / QUALITY
Cylinder/Beam
Compression/Flexural
strengths
Note: At the point concrete is
deposited, a minimum of one
set per class of concrete per
day is required.
Pavement Thickness (except
existing subdivision
concrete replacement)
FREQUENCY
Air Content, Temperature, Slump
and Two routine (6” x 12”) cylinder
specimens (one set for 28-day
compressive strength) should be
made on the job site, at the
beginning of each pour, for each
class of concrete and supplier, and
every 200 c.y. thereafter. Air,
Temperature and Slump tests are
mandatory for each set of cylinders
cast. Cylinders are to be delivered
to
the
Materials
Lab
for
Compressive Strength Testing
within 48 hours of casting. Testing
by Project Inspector
A minimum of four cores (one set)
per 1,000 centerline ft. of pavement.
The drilling of cores in irregular
areas, Paved Approaches, or when
plan quantity is less than 2,500 s.y.,
may be waived by the Engineer.
Testing by Material Testing
Inspector
FORM
C50M
C-82,
C-86
Arterial Roads and new subdivision streets > 26 ft in width:
Depth Check
0 to +1/2 in.; four checks per 2-lane
width per 1 /2 Station (50 ft).
Testing by Project Inspector
Field
Book
By 10 ft straightedge:
Surface Tolerances
Parallel to centerline- 3/8 in. ;
Transverse construction joints- 1/4
in Testing by Project Inspector
Field
Book
New Subdivision streets ≤ 26 ft in width:
Depth Check
Surface Tolerances
Core drilling by Materials Testing
Field Section
C-82,
C-86
By 10 ft straightedge: Parallel and
Transverse- 1/2 in. Testing by
Project Inspector
Subdivision Concrete Replacement:
266
Original Date: 1/3/94
Revised Date: 05/27/16
MATERIAL
PROPERTY / QUALITY
FREQUENCY
FORM
Depth Check and
Surface Tolerances,
Pavement Thickness, and
compressive strength of
cores
Air Content, Temperature, Slump
and Two routine (6” x 12”) cylinder
specimens (one set for 28-day
compressive strength) should be
made at the beginning of each pour
for each class of concrete and
supplier and at the below intervals.
Cylinders are to be delivered to the
Materials Testing Concrete Lab for
Compressive Strength Testing
within 48 hours of casting. Testing
by Project Inspector
General
Division 700
Portland Cement Concrete
Structures
All as per contract documents.
Testing by Materials Lab/Field &
Project Inspector
C-82,
C-86,
C-502
C50M
Air Content, Temperature, Slump and set of cylinders:
NOTE: AT THE POINT CONCRETE IS DEPOSITED, A
MINIMUM OF ONE SET PER CLASS OF CONCRETE PER
DAY IS REQUIRED.
Grated Troughs and Inlets,
Cast-in-Place Inlet or
manhole structures
One test, by Project Inspector, per
structural unit.
Retaining Walls, Bridge
Substructure
One test, by Project Inspector, per
100 c.y. thereafter.
Bridge Deck, Superstructure
One test, by Project Inspector, per
50 c.y. thereafter.
Temperature
Temperature is recorded on the
invoice from the first load and then
every third load. Testing by Project
Inspector.
C-
Section 405
Bituminous Asphalt Pavement
(except medians or similar
areas, shoulders adjacent to
50M
267
Original Date: 1/3/94
Revised Date: 05/27/16
MATERIAL
PROPERTY / QUALITY
FREQUENCY
Density and Thickness
One density test (nuclear density
gauge) per lift per type per every
2,000 lane ft. Penalties cored/sawed
for density tested at one set (four
cores/one sawed) per 500 ft.
intervals. All penalties will be
cored. One set of cores taken per
day for density, thickness and
composition. Additional cores may
be taken at the Project Resident
Engineer’s or assignee’s discretion.
Testing performed by Materials Lab
Field Section and Soils Lab.
rigid pavement, asphalt curb
mix and temporary pavements)
FORM
C-20
All Pavement, including new Subdivision Pavement > 26 ft wide:
By 10 ft straightedge:
Surface Tolerance
Parallel to centerline- 3/8 in.
Transverse construction joints- 1/4
in. Testing performed by Project
Inspector.
New Subdivision Pavement ≤ 26 ft wide:
Surface Tolerance
Asphaltic Concrete Pavement
(Superpave)
Microsurfacing
Section 407 or 408
Tack or Prime
Temperature,
Density,
Surface
Tolerance
and
Thickness
Gradation, Binder Content
In accordance with Section
1015
By 10 ft straightedge: Parallel and
Transverse- 1/2 in. Testing by
Project Inspector
Same as for Bituminous Asphalt Pavement See Contract Documents
Before production, one sample per
stockpile by Materials Lab Field
Inspector to Soil Lab. During
production one sample from behind
paver during the first day of
production by the Project Inspector
and then one sample every 5th day of
production. Sample delivered to the
Binder Lab by the Project Inspector
for Extraction and gradation. See
Contract Documents.
C-91
Project Inspector to submit one
quart sample per source per
distributor delivery of material, with
certification, to Binder Lab.
268
Original Date: 1/3/94
Revised Date: 05/27/16
MATERIAL
PROPERTY / QUALITY
FREQUENCY
Section 604
Brick (On jobs with more than
100 pieces)
Dimensions, absorption
Project Inspector to submit sample
of 5 bricks to Concrete Lab for
testing.
C-66
Project Inspector to submit two bars
from the largest and the smallest
sizes of each heat number (36 in. in
length). For each heat number, one
additional 36” long bar from each
alternate size, beginning with the
smallest size bar. Project Inspector
to submit bar(s), tagged with heat
number, project name and structure
location, with mill tests reports to
Concrete Lab for testing on the 1st or
15th of the month.
C-67
Project Inspector, for each shipment
of pipe, to visually compare delivery
invoice to materials delivered
regarding pipe classification and
condition
(cracks,
exposed
reinforcement, etc.)
C-23
Section 706
Reinforcing Steel for Bridge,
Box Culvert, Retaining Wall
Construction
Section 726
Concrete and Clay Pipe
(Tensile, Yield, Elongation,
and Bend Tests)
Field verify
Classification
Condition,
FORM
NOTES:
1.
When aggregate base shown in the contract is to be measured and paid for by area, conversion of the area
quantity to tons can be made by multiplying the thickness (in.) by the square yards of area covered by 0.06
tons/s.y./1” thickness.
2.
When concrete shown in the contract is to measured and paid for by area, conversion of the area quantity
to cubic yards (c.y.) can be made by multiplying the thickness (in.) by the square yards of area covered by
0.028 cy/sy/1” thickness.
3.
Forms located in Materials Testing Laboratory Quality Control Manual.
The following information establishes procedures for LPA Federal-Aid Acceptance Sampling
and Testing (FAST) for all Federal-Aid projects awarded and administered by MoDOT. If a local
public agency receives federal funds from MoDOT but does not specify, the guidelines in this
Off-Systems Guide Schedule for Federal-Aid Acceptance Sampling and Testing (FAST) table
should be followed. The acceptance sampling and testing procedures for other materials and
construction processes are to be as shown in other articles in the Engineering Policy Guide.
269
Original Date: 1/3/94
Revised Date: 05/27/16
TABLE 1017C – OFF-SYSTEMS GUIDE SCHEDULE FOR FEDERAL-AID
ACCEPTANCE SAMPLING AND TESTING
Type of Construction or
Material
Tests to be Made (if
specified)
Sampled
Minimum Number of Tests
Grading - Embankment
Density/Moisture
After
compaction
A minimum of 4 density tests per day
for each active grading spread
regardless of road surface
Subgrade Preparation
Density/Moisture
After
compaction
A minimum of 4 density tests per day
for each active grading spread
regardless of road surface
Gradation
Before
compaction
One per 2000 tons or fraction thereof
per specified gradation per source.
Density/Moisture
After
compaction
A minimum of 4 density and
moisture tests per day for Type 1 and
5 aggregate and 4 penetration and
moisture tests for Type 7 aggregate.
Plasticity Index
Before
compaction
One per project per specified
gradation, per source.
Gradation
Before
compaction
One per 2000 tons or fraction thereof
per specified gradation per source.
Density
After
compaction
A minimum of 4 density and
moisture tests per day
Liquid Limit
Before
compaction
One per project per specified
gradation, per source.
Plasticity Index
Before
compaction
One per project per specified
gradation, per source.
Aggregate Base1
Type 1, 5, 7 or
Stabilized Permeable2
(roadway and
shoulders)
Sand-Soil Base or SoilCement Base or SoilLime Base
Crushed Stone or
Gravel Surfacing
Gradation
-
One per project per specified
gradation, per source. Less than 500
tons accepted on certification.
Plant Mix Bit. Base or
Plant Mix Bit.
Gradation
Before
mixing
One per 500 tons or fraction thereof
per mix type. None required if mix
270
Original Date: 1/3/94
Revised Date: 05/27/16
Pavement or Asphaltic
Concrete Pavement
type is less than 50 tons/day or 250
tons/project.
2 roadway cores/day and 2
longitudinal unconfined joint
cores/day < 100 tons
After
compaction
Density
4 roadway cores/day and 4
longitudinal unconfined joint
cores/day ≥ 100 tons. Random
Procedures per ASTM D 3665-07.
Asphalt Content
Before
compaction
One per day, using an approved
AASHTO method for determining
asphalt content.
Gradation (both coarse and
fine aggregates)
Batch plant
One per 2000 cubic yards or fraction
thereof per specified gradation, per
source.
Deleterious (coarse
aggregate)
Batch plant
One per 2000 cubic yards or fraction
thereof per specified gradation, per
source.
Jobsite
Air and consistency tests are to be
made at the beginning of each pour
and for each 100 cubic yards/mix
design/pour/day thereafter.
Compressive Strength
Jobsite
One set3 of specimens should be
made at the beginning of each pour
and every 100 cubic yards/mix
design/pour/day thereafter. 4
Gradation (both coarse and
fine aggregates)
Batch plant
One per 1000 cubic yards or fraction
thereof per specified gradation, per
source.
Deleterious (coarse
aggregate)
Batch plant
One per 1000 cubic yards or fraction
thereof per specified gradation, per
source.
Air Content/Slump
Jobsite
Air and consistency tests are to be
made at the beginning of each pour
PCC Pavement or PCC
Base
Air Content/Slump
Concrete Masonry
Structural items
including but not limited
to: Bridges, CIP retaining
walls, box culverts,
bolted-down footings
271
Original Date: 1/3/94
Revised Date: 05/27/16
and for each 100 cubic yards/mix
design/pour/day thereafter.
Compressive Strength
Jobsite
One set3 of specimens should be
made at the beginning of each pour
and every 100 cubic yards/mix
design/pour/day thereafter. 4
Gradation (both coarse and
fine aggregates)
Batch plant
One per 1000 cubic yards or fraction
thereof per specified gradation, per
source.
Deleterious (coarse
aggregate)
Batch plant
One per 1000 cubic yards or fraction
thereof per specified gradation, per
source.
Jobsite
Air and consistency tests are to be
made at the beginning of each pour
and for each 100 cubic yards/mix
design/pour/day thereafter.
Compressive Strength
Jobsite
One set3 of specimens should be
made at the beginning of each pour
and every 100 cubic yards/mix
design/pour/day thereafter when the
total quantity on the concrete tickets
per mix design is ≥ 3cy.5
Precast Items
Gradation/Deleterious/Air
Content/Slump
Manufacture
Plant
Obtain plant certification when using
MoDOT approved plant otherwise
quality plan will need to be
submitted.
Coating of Structural
Steel6
Environmental
Conditions/Surface
Profile/Mil Thickness
Jobsite
One test/day as it applies for working
being performed
Concrete Masonry
Incidental Concrete (curb
& gutter, sidewalk, etc.)
Air Content/Slump
1
When aggregate base shown in the contract is to be measured and paid for by area, convert the area to tons and
follow the sampling frequency shown in this table. When converting, use the factor .06 tons/sq. yd./1 in.
thickness of compacted base.
2
Gradation only for Type 4 and Stabilized Permeable Base.
One set of cylinders shall consist of 2 - 6” x 12” cylinder molds or 3 - 4” x 8” cylinder molds. To determine if
ultimate (contractual) strength has been obtained, one set of cylinders must be tested and the average strength of
all cylinders will determine ultimate strength of in place concrete.
3
272
Original Date: 1/3/94
Revised Date: 05/27/16
4
Air and slump tests are required for each set of cylinders created.
5
Compressive strength test can be waived if the concrete to be placed in any one day is less than 3 C.Y. and an
air, slump, and compressive strength test was performed the preceding day on that class of concrete.
6
Painting contractor is required to be part of certification program such as NACE, SSPC or equivalent.
TABLE 1017D – COMMON CONSTRUCTION MATERIALS REQUIRING
CERTIFICATIONS
Section
Material
Certified Test Results
Remarks
Sec. 403
Geosynthetic Material
Section
1011.3.7,
1011.3.8, or 1011.3.9
As Specified in
Contract
Documents
Sec. 407, Tack Coat
Emulsified
Asphalt
(CPEM-1, SS-1, SS-1H,
CSS-1, or CSS-H)
Section 1015
Test
Samples
May
be
Required
Sec. 408, Prime Coat
Type MC Liquid Asphalt
Section 1015
Test
Samples
May
be
Required
Emulsified
Asphalt
(CPEM-1, SS-1, SS-1H,
CSS-1, or CSS-H)
Section 1015
Test
Samples
May
be
Required
Sec. 603 Miscellaneous
Water Equipment
Seamless Copper Water
Tube
ASTM B88 Type K
Sec. 701 Drilled Shafts
Casings
ASTM A252 Grade 2
Sec. 702 Bearing Pile
Structural Steel Pile
Section 702.2.6
Structural Steel Thick
Shells for Cast-In Place
Section 702.2.6
Sec. 706 Reinforcing
Steel
for
Concrete
Structures
Mechanical Bar Splice
Systems
Section 706.3.3
Sec. 802, Mulching
Mulch
Section 802.2.2
Sec.
806,
Pollution,
Sediment, and Erosion
Control
Temporary
Erosion
Control Blanket
Section 1011.3.6
Sec. 904 Traffic Control
Facilities
Controller
Equipment
NEMA
Standards
Publication No. TS 2
Cabinet
Test
Samples
May
be
Required
273
Original Date: 1/3/94
Revised Date: 05/27/16
Type 2 Traffic Control
Systems
Sec. 1011 Geotextile
Geotextiles
AASHTO M288, MARV
Sec. 1012 Geocompsite
Drainage Material
Edge Drain
Section 1012.3.2
Vertical Drain at End
Bent
Section 1012.3.3
Corrugated
Choride Pipe
ASTM F949
Sec. 1013, Miscellaneous
Drainage Material
Polyvinyl
Smooth Wall Polyvinyl
Choride Pipe
ASTM D3034
Schedule 40
Choride Pipe
ASTM D1785
Polyvinyl
Corrugated High Density
Polyethylene Pipe
AASHTO M252 Type S
or SP
Corrugated Double Wall
Polypropylene Pipe
ASTM 2736
Corrugated Triple Wall
Polypropylene Pipe
ASTM F2764
Sec. 1020, Corrugated
Metallic Coated Steel
Culvert
Pipe,
Pipe
Arches, and End Sections
Corrugated
Metallic
Coated Steel Culvert
Pipe, Pipe Arches, and
End Sections
Section 1020
Sec. 1022, Corrugated
Metallic Coated Steel
Pipe Underdrain
Corrugated
Metallic
Coated
Steel
Pipe
Underdrain
AASHTO M36 Type III
Sec. 1026, Reinforced
Concrete Culvert, Storm
Drain and Sewer Pipe
Reinforced
Concrete
Culvert, Storm Drain and
Sewer Pipe
AASHTO M170
Type A Rubber Gaskets
AASHTO M198
Deformed Bars
Section 1036.3.1
Test
Samples
May
be
Required
ASTM A1064
Test
Samples
May
be
Required
Section
Reinforcing
Concrete
Steel
1036,
for
Steel
Welded
Reinforcement
Section
1037
Connectors
Shear
Wire
Studs
Section 1037
Elastomeric Bearing Pads
Section 1038.3
274
Original Date: 1/3/94
Revised Date: 05/27/16
Type
“N”
Poytetrafluoroethylene
Bearing Pads
Section 1038.4
Rubber and Fabric Pads
Section 1038.5
Rubber and Fiber Pads
Section 1038.6
Epoxy or Polyester Resin
for Dowels
Section 1039.30
Epoxy Bonding Agents
for Resin Anchor Systems
Section 1039.40
Polymer Concrete
Section 1039.70
Wood Post and Blocks
Section 1040.2
Steal Beam Guard Rail
Section 1040.3
Crashworthy
Terminal
End
Section 1040.4
End Anchors and Bridge
Anchors
Section 1040.5
Cable and Fittings
Section 1040.6
Polypropylene
Culvert
Pipe Double Walled
ASTM F2736
Polypropylene
Culvert
Pipe Triple Walled
ASTM F2764
Fabric
Section 1043.2
Post, Braces, Rails, and
Gate Frame
Section 1043.2.5
Section 1045, Paint for
Structural Steel
Coating and Primer
Section 1045
Section 1048, Pavement
Marking Material
Preformed
Removable
Pavement Marking Tape
Section 1048.4
Drop On Glass Beads
Section 1048.6
Temporary
Markers
Section 1048.7
Section 1038, Bearing
Pad for Structures
Section 1039
Resin Material
Epoxy
Section 1040, Guardrail,
End Terminals, OneStrand Access, Restraint
Cable, and Three Strand
Guard Cable Material
Section
Polypropylene
Pipe
Section 1043,
Material
104,
Culvert
Fence
Lane
Acrylic Copolymer Fast
Drying
Pavement
Marking Paint
Section 1048.11
Acrylic
Waterborne
Pavement Marking Paint
Section 1048.12
275
Original Date: 1/3/94
Revised Date: 05/27/16
Section
1052,
Mechanically Stabilized
Earth Wall System
Geogrid
Section 1052.3.1
Small Block Wall SystemConcrete Blocks
Section 1052.5
Section
1053,
Penetrating Protective
Sealer Material
Penetrating
Protective
Sealer Material
Section 1053.3
Section 1054, Concrete
Admixtures
Air entraining Admixture
Section 1054.3.2
Water
Admixture
Section 1054.4.2
Section 1055, Concrete
Curing Material
Section 1057, Material
for Joints
Reducing
Non
–Chloride
Accelerating Admixture
AASHTO M194 Type C
or E
Chloride
Admixture
AASHTO M144
Accelerating
Type
1-D
Compound
Curing
Section 1055.4.2.3.1
Type
2-D
Compound
Curing
Section 1055.4.2.3.2
Dissipating
Compounds
Curing
Section 1055.4.2.3.3
Corrosion-Resistant
Coated Dowel Bars
AASHTO M254, Type B
(ASTM A615) Grade 40
or Grade 60
Joint and Crack Sealer,
Hot Poured Elastic Type
Section 1057.5
Preformed
Fiber
Expansion Joint Filler
Section 1057.5.2
Backer Material Used
with Cold and HotApplied
in
Portland
Cement and Asphalt
Joints
Section 1057.5.3
Polyurethane Elastomeric
Joint Sealer
Section 1057.6
Polyvinyl Chloride Water
Stop
Section 1057.7.1
Rubber Water Stop
Section 1057.7.2
Test
Samples
May
be
Required
276
Original Date: 1/3/94
Revised Date: 05/27/16
Section 1080 Structural
Steel Fabrication
Preformed Spong Rubber
Expansion and Partition
Joint Filler
Section 1057.7.4
Silicone Expansion Joint
Sealer
Section 1057.10
Silicone Joint Sealant for
Sawcut and Formed
Joints
Section 1057.11
Structural Steel
Section 1080.2.4
High Strength Fastener
Assembly
Section 1080.2.5
277
Original Date: 1/3/94
Revised Date: 05/27/16