JAB Plastic
Products Corp.
Technical Information
WHAT DO CURRENT DESIGN CODES,
STANDARDS AND MANUALS OF PRACTICE
REQUIRE?
UNIFORM BUILDING CODE (UBC)
1997 UBC, VOLUME 2 – STRUCTURAL
ENGINEERING DESIGN PROVISIONS
• Chapter 19, Section 1907.5 – Placing
Reinforcement
• Chapter 19, Section 1907.6 – Spacing
Limits for Reinforcement
• Chapter 19, Section 1907.7 – Concrete
Protection for reinforcement
• Same requirements as for the International
Building Code (IBC)
INTERNATIONAL BUILDING CODE (IBC)
•Section 1907.5.1 – Bar Support:
Reinforcement bar shall be accurately
placed and adequately supported before
concrete is placed, and shall be secured
against displacement within tolerances.
• Section 1907.5.2 – Tolerances:
For Slab depth, d  8 inches;
d, ± 3/8 inch
concrete cover, – 3/8 inch
For Slab depth, d > 8 inches;
d, ± 1/2 inch
concrete cover, - 1/2 inch
Tolerance for Cover shall not exceed
minus 1/3 the minimum concrete cover
required by the approved plans or
specifications.
IBC REQUIREMENTS, CONT.
•Section 1907.6 –
Minimum space between bars in slab must
comply with ACI 318, Section 7.6.
Smin. horizontally or vertically = One Bar
Diameter or 1 inch
• Section 1907.7.1 –
Minimum concrete cover for non pre-stressed
cast in place concrete:
Concrete permanently expose and cast
against soil – 3”
Concrete expose to soil or weather:
For #6 through #18 Bar – 2”
For #5 & W31 or D31 or
smaller – 1½”
IBC REQUIREMENTS, CONT.
Concrete not expose to weather or in
contact with soil:
For slab - #11 bar or
smaller - ¾ inch
AMERICAN ASOCIATION OF STATE
HIGHWAY AND TRANSPORTATION
OFFICIALS (AASHTO)
• Standard Specification, Division I – Design,
Section 8.21 provides a minimum distance
between reinforcement bars:
AMERICAN ASOCIATION OF STATE
HIGHWAY AND TRANSPORTATION
OFFICIALS (AASHTO), CONT.
For bridges’ cast in place concrete slab:
Smin. = 1½ Bar Diameter or
1½ Max. Diameter of
Coarse Aggregate or
1½ inches
• Standard Specification, Division I – Design,
Section 8.22, Minimum concrete covers:
Concrete expose to soil or weather:
Primary reinforcement – 2”
Stirrup, tie-up, spiral - 1½”
AMERICAN ASOCIATION OF STATE
HIGHWAY AND TRANSPORTATION
OFFICIALS (AASHTO), CONT.
• Standard Specification, Division I – Design,
Section 8.22, Minimum concrete covers:
Concrete slabs exposed to mild climates:
Negative reinforcement – 2”
Positive reinforcement - 1”
Concrete slabs without positive corrosion
protection and frequently exposed to
deicing salts:
Negative reinforcement – 2½”
Positive reinforcement - 1”
AMERICAN ASOCIATION OF STATE
HIGHWAY AND TRANSPORTATION
OFFICIALS (AASHTO), CONT.
• Standard Specification, Division I – Design,
Section 8.22, Minimum concrete covers:
Concrete slab not expose to weather or
in contact with soil:
Primary reinforcement – 1½”
Stirrup, tie-up, spiral - 1”
• Standard Specification, Division II – Const.,
Section 9.6, Placing and tie-up of reinforcement
bars – requires:
• Tie-up all reinforcement bar intersection
around the perimeter of the steel mat.
AMERICAN ASOCIATION OF STATE
HIGHWAY AND TRANSPORTATION
OFFICIALS (AASHTO), CONT.
•Tie-up every two (2) feet maximum
center to center or at any other
intersection, the greater of the two,
for the rest of the bar intersections.
• Section 9.6.2 – “reinforcement bar could
be supported on any approved
mechanism.
• Use sufficient supports to maintain the
steel bar in position in order to keep
the distance between bars and forms or
the slab surface within tolerance - ¼ inch
of specified on plans or specifications.
•The weight of workers and equipments
must be supported against the forms not
against the reinforcement bars.
MANUALS OF STANDARD PRACTICES IN
THE CONSTRUCTION INDUSTRY
• CONSTRUCTION INSPECTION MANUAL
FOR REINFORCED CONCRETE STRUCTURES
BY THE AMERICAN CONCRETE INSTITUTE
(ACI SP-2 (99))
• STANDARD PRACTICES FOR REINFORCING
STEEL DETAILING BY THE CONCRETE
REINFORCING STEEL INSTITUTE (CRSI)
MANUALS OF STANDARD PRACTICES IN
THE CONSTRUCTION INDUSTRY
• Steel rebar shall be firmly supported in place.
• Reinforcement supports shall be of adequate
capacity and sufficient chairs be placed at the
right locations to support the reinforcement
steel and the construction loads at which it will
be subject to prevent the sagging of the steel
and reducing the distance between the steel
and the forms or earth base.
• Allows the use of plastic chairs among other
materials. Do not use rocks, wood blocks or
other materials not approved for rebar support.
MANUALS OF STANDARD PRACTICES IN
THE CONSTRUCTION INDUSTRY
• In general, support horizontal bars at every
5 or 6 feet.
• Tie-up intersected steel bar at a maximum
of 2 or 3 feet or every other intersection.
• To prevent corrosion and to avoid any
surface stains use plastic chairs or
stainless steel chairs.
STANDARD TESTS PERFORMED ON
JAB SNAP-ON & SUPPORT SYSTEM.
TEST #1 (COMPRESSION)
Figure 3 – Arrangement Used during the Compression Test
Load vs. Displacement Curve for 1.5" Chair and # 3 Rebar
750
PLASTIC CHAIR FOR 1.5" CONCRETE COVER
Test # 5 Pmax = 687 Lbs - Type 1 Failure
700
650
600
550
500
Test #3 Pmax = 550 Lbs - Type 2 Failure
450
Load (Lbs)
400
Test # 2 Pmax = 486 Lbs - Type 2 Failure
350
300
250
Test #1 Pmax = 440 Lbs - Type 2 Failure
Test #4 Pmax = 439 Lbs - Type 2 Failure
200
150
100
50
0
0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 0.20 0.22 0.24
-50
Displacement (in)
Load vs. Displacement Curve for 1.5" Chair and # 4 Rebar
PLASTIC CHAIR FOR 1.5" CONCRETE COVER
600
Test # 4 Pmax = 565 Lbs - Type 1 Failure
550
500
450
Test # 5 Pmax = 516 Lbs - Type 1 Failure
400
Test # 3 Pmax = 523 Lbs - Type 1 Failure
Load (Lbs)
350
300
Test # 2 Pmax = 419 Lbs - Type 2 Failure
250
Test # 1 Pmax = 353 Lbs - Type 2 Failure
200
150
100
50
0
0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 0.20 0.22 0.24
Displacement (in)
STANDARD TESTS PERFORMED ON
JAB SNAP-ON & SUPPORT SYSTEM.
TEST #2 (SEGREGATION)
Core Sample - Chair 2.5”
Core Sample - Chair 1.5”
Core Samples
STANDARD TESTS PERFORMED ON
JAB SNAP-ON & SUPPORT SYSTEM.
TEST #3 (SLAB BENDING)
SLAB BENDING TEST
For the test, three (3) reinforced concrete slabs with measurements
of ten (10) feet long, four (4) feet wide and four (4) inches thick were
built. The objective of the test was to locate the chairs within the
slabs in similar conditions to which they will be subjected in
everyday use, and load test the slabs to determine if the use of the
JAB plastic chairs results in localized cracks or fissures around the
chairs or the development of any unexpected crack patterns along the
width of the slab. The three (3) specimens built for testing differ
from each other in the amount of steel or steel ratio used. For slab
number 1, four (4) - #3 rebar were used. For the slab number 2, five
(5) - #3 rebar were used. For slab number 3, seven (7) - #3 rebar were
used. Based on these parameters, slab #1 should support under
service load conditions, 20 pounds/ft2 of live load in addition to its
own weight, slab #2 - 30 pounds/ft2 of live load and the slab #3 - 40
pound/ft2 of live load.
Figure 9 – General View of Slab forms, chairs and rebar before
pouring concrete
Figure 9 illustrates a general view of the specimens showing
the location of the plastic chairs and the steel before pouring
the concrete. The concrete used for these tests was pre-mixed.
The maximum size of the coarse aggregate was ¾” nominal
diameter. The average of six (6) cylinders, concrete
compressive strength (f’c) was 2,310 psi at 28 days. This f’c
was inferior to those normally specified in common
construction for structural members (e.g. 3,000 psi).
Figure 10 – Block load application sequence used during the
testing
Figure 10 shows markings drawn to identify the sequence
and the location of the blocks upon the slab. It was
designed to simulate a uniform distributed load after all
concrete blocks were in placed.
Figure 11 shows one of the reinforced concrete slabs
during the loading procedure. Before starting the test,
various blocks of 6” x 8” x 16” were weighed and an
average weight was calculated to compute the number of
blocks needed for each specimen. With an average weight
of 30 pounds, 27 blocks were located over slab #1, 40
blocks were located over slab #2 and 54 blocks were located
over slab #3 to simulate the corresponding live loads of
approximately 20 pounds/ft^2, 30 pounds/ft^2 and 40
pounds/ft^2, respectively.
Figure 11 - General View of the Load applied to Slab 1
Figure 12 illustrates the cracks pattern observed during the tests. On
each of the slabs, cracks begin to appear after 20 blocks have been placed
on the slab. The cracks appear on or near the center and extended all over
the width of slab. No crack concentrations were found around the
chairs or along the slab where the chairs were located. No crack
patterns different from what normally can be found in reinforced
concrete slab with steel wire or cement mortar (“limbers”) rebar
supports subject to bending were observed.
The difference found between each one of the specimens was not in
the crack pattern but in the amount of cracks found along the width of the
slab and the measurement (width) of the crack. The difference was
expected since the load applied was doubled from slab #1 to slab #3.
Figure 12 – Crack Pattern on the Central Zone of Slab 3
STANDARD TESTS PERFORMED ON
JAB SNAP-ON & SUPPORT SYSTEM.
TEST #4 (FILTRATION)
Figure 13 – Arrangement Used during the Filtration Tests
Figure 14 – Bottom View of Concrete Slab alter 10 days
Slab Filtration Test
With the objective of evaluating if placing the JAB plastic chairs
instead of the metallic or mortar supports could contribute to develop a
localized filtration condition in the slab, a test was specifically designed
to evaluate the effect of the plastic chairs in the filtration pattern. The test
consisted in maintaining 1.5 inches of water on the surface of slab for ten
(10) days. During this period of time, the filtration pattern was visually
observed, evaluating specifically if the water filtration was somehow
increased or different around the zones where the plastic chairs were
located. Figure 13 shows the arrangement used for the tests. Figure 14
shows that after 10 days of maintaining the top portion of the slab
submerge in water, no filtration marks were noticed around the
location of the chairs nor along any of the cracks under the slab. The
daily observation made under the slab during the preceding 9 days
concurs with the final observation at day 10 of the test.
JAB SNAP-ON & SUPPORT SYSTEM
INSTALLATION PROCEDURES
• REBAR QUANTITY AND INSTALLATION PATTERNS
SHOULD BE AS INDICATED BY THE JAB PLASTIC CHAIR
QUANTITY CALCULATOR, BUT FOR THE MOST PART
THE FOLLOWING RESTRICTIONS APPLY:
– TO AVOID SAGGING OF THE REBAR, LOCATE CHAIRS AT A
DISTANCE NOT GREATER THAN:
• FOR #3 OR 3/8” BARS - 2 FEET CENTER TO CENTER
• FOR #4 OR ½” BARS - 3 FEET CENTER TO CENTER
• FOR #5 OR 5/8” BARS - 4 FEET CENTER TO CENTER
– FOR BIGGER BAR NUMBERS, CHAIRS SHALL IN NO EVENT BE
LOCATED FARTHER APART THAN 5 OR 6 FEET CENTER TO CENTER
– TO ELLIMINATE THE USE OF TIE-UP WIRES, LOCATE PLASTIC
CHAIRS AT A DISTANCE OF 2 FEET OR LESS CENTER TO CENTER IN
BOTH DIRECTIONS
JAB SNAP-ON & SUPPORT SYSTEM
INSTALLATION PROCEDURES,
CONT.
• ALWAYS VERIFY THAT REBARS ARE LOCATED AT
THE RIGHT POCKET FOR PROPER GRIP. THE GRIP
PROVIDED BY THE SNAP-ON FEATURE OF THE CHAIR
IS STRONG ENOUGH TO KEEP REBAR IN PLACE,
THEREFORE EXCEEDING CODE REQUIREMENTS.
• ALWAYS VERIFY THE REQUIREMENTS OF THE CRSI
STANDARD PRACTICE OR STEEL DETAILING
MANUALS FOR PROPER LOCATION OF THE CHAIRS
– THERE ARE SPECIFIC AND DIFFERENT REQUIREMENTS
FOR EACH TYPE OF STRUCTURAL SLABS AND SLAB ON
GRADE
PRODUCTS AVAILABLE FOR DELIVERY NOW!
HEAVY DUTY 1.5” INCHES HIGH
FOR #2, #3 & #4 REBARS
& 6x6-10x10 WIRE MESH
HEAVY DUTY 2.5” INCHES HIGH
FOR #3, #4 & #5 REBARS
PRODUCTS AVAILABLE FOR DELIVERY NOW!
HEAVY DUTY .75” INCHES HIGH
FOR #3, #4 & #5 REBARS
•DOUBLE MAT SYSTEM FROM 2” TO 8”
•FOR #3, #4, #5, #6, #7 & #8 BAR SIZES
PRODUCTS AVAILABLE FOR DELIVERY NOW!
STANDARD CROWN 1 (1.5”,2.0”,2.5” and 3.0”) INCHES HIGH FOR #2, #3, #4
REBARS & 6x6-10x10 WIRE MESH .
STANDARD CROWN 2 (2.0”to 8” INCHES HIGH FOR #3, #4 and #5 REBARS
PRODUCTS AVAILABLE UPON REQUEST
FROM JAB PLASTIC PRODUCTS CORP.
• SINGLE MAT CHAIR FROM .75” TO 8”
•FOR #3, #4, #5 BAR SIZES
• DOUBLE MAT CHAIRS FROM 2” TO 14”
•FOR #3, #4, #5, #6, #7 & #8 BAR SIZES
JAB Plastic Snap On and Support System.
“The new way to improve the old way”
• MEETS CODES/STANDARDS REQUIREMENTS
• MEETS STANDARD PRACTICE REQUIREMENTS
• SURPASSES EXPECTED CONSTRUCTION LOADS
• AVOID CORROSION STAINS
• PROVIDES REQUIRED TIE-UP REDUCING LABOR
INTENSIVE COST
• COST SAVINGS
• COMPETITIVE COST
FOR INFORMATION ABOUT OUR
PRODUCTS PLEASE CONTACT:
JORGE ALFONSO
PRESIDENT
CELLULAR PHONE: (210) 859-4110
FAX NUMBER:
1(888) 836-4068
Jab Plastics Chairs Products
• 1.5” Plastic Concrete Chair
• 2.5” Plastic Concrete Chair
• 1/2” Plastic Anchor Bolt Cap
• 5/8” Plastic Anchor Bolt Cap
The new way
to improve the old way
JAB PLASTIC PRODUCTS CORP.
P.O.Box 11528 Austin , TX 78711-11528
www.jabplastic.com