This master should be used by designers working on Port of Portland construction projects and by designers working for PDX
tenants (“Tenants”). Usage notes highlight a few specific editing choices, however the entire section should be evaluated and
edited to fit specific project needs.
SECTION 312000 – SITE CLEARING AND EARTHWORK
PART 1 - GENERAL
1.1
DESCRIPTION
A.
This section describes site clearing, excavation, stockpiling, embankment, grading, riprap,
subgrade preparation, and construction of the subbase.
B.
If the Contractor encounters suspected contaminated soil in the work area beyond that
mentioned in the contract documents, the Contractor shall immediately stop all work in the area
of the suspected contamination and notify the Port. Contaminated soil is soil that produces fuel
or chemical odors, produces an oil sheen on the surface of water, has staining, contains debris or
other visible indicators, or soil designated by the Port as contaminated. The Port will
characterize contaminated soil, obtain profile for disposal, and determine the location of
disposal.
1.2
REFERENCES
A.
AASHTO: American Association of State Highway and Transportation Officials
1.
AASHTO T180: Standard Method of Test for Moisture-Density Relations of Soils Using
a 4.54-kg (10-lb) Rammer and a 457-mm (18-in.) Drop
B.
ASTM: American Society for Testing and Materials
1.
ASTM D2922: Standard Test Methods for Density of Soil and Soil-Aggregate in Place
by Nuclear Methods (Shallow Depth)
C.
ODOT: Oregon Department of Transportation – 2002 Standard Specifications
1.
ODOT Section 00390.11: Riprap Requirements
2.
ODOT Section 00390: Riprap Protection
3.
ODOT Section 02630: Base Aggregate
1.3
RELATED WORK SPECIFIED ELSEWHERE
Always include Section 015713 when using this section.
A.
Section 015713, Temporary Erosion, Sediment, and Pollution Control
B.
Section 024113, Site Demolition
C.
Section 026100, Removal and Disposal of Contaminated Soils
D.
Section 312300, Trenching, Backfilling, and Compacting
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1.4
DEFINITIONS
A.
Clearing and Grubbing: Trees, stumps, brush, roots larger than one inch in diameter, other
vegetation, and debris removed.
B.
Common Excavation: Material, regardless of condition, excavated from the work area that is
not classified elsewhere.
C.
Stripping: Grass, sod, and other types of vegetation removed.
D.
Unsuitable Excavation:
1.
Material excavated from the site determined not usable as subgrade fill or topsoil.
2.
Material that does not meet the requirements specified below for suitable material.
3.
Material that is contaminated or otherwise determined by the Port to be unsuitable for
reuse as fill on Port property.
4.
Debris or material containing excessive amounts of debris.
PART 2 - PRODUCTS
2.1
SUITABLE MATERIAL
A.
Common Excavation:
1.
Sand: Columbia River dredged sand separated from other common excavation materials.
2.
Topsoil: Material made of fertile, loamy, surface soil, capable of supporting plant life,
consisting of a mixture of sand, silt, clays, and organic material. Topsoil shall be free of
debris.
Choose B or C.
B.
Borrow:
1.
Sand: Columbia River dredged sand obtained from the designated borrow site.
2.
Topsoil: Material obtained from the designated topsoil borrow site.
C.
Imported Backfill:
1.
Columbia River sand obtained from an approved source, or
2.
Crushed Aggregate: ODOT Section 02630, 1"-0" or 3/4"-0".
Use for a small quantity of riprap placed on geotextile backing. Choose Class 100 or 200.
2.2
RIPRAP
A.
2.3
In accordance with ODOT Section 00390.11, Class ____.
GEOTEXTILE
A.
Amoco 4553, or equal.
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PART 3 - EXECUTION
3.1
GENERAL
Tenants: Delete “Port” and replace with “tenant.”
A.
The Port will designate the disposition and determine the suitability of products.
B.
The right is reserved to make minor adjustments or revisions in line or grades, if found
necessary as the work progresses.
C.
No excavation or stripping shall be started until the Contractor has staked out the proposed
work.
D.
Suspend earthwork when satisfactory results cannot be obtained because of rain, freezing
weather, or other unsatisfactory conditions.
E.
Drag, blade, or slope the grade to provide proper surface drainage. Install temporary drains and
drainage ditches to intercept or divert surface water which may affect the prosecution or
condition of the work.
F.
Excavate and place embankment to such depth that sufficient material will be left above the
designated grade to allow for compaction to the proper grade. Replace material excavated
below the designated lines with approved materials, in an approved manner and condition, at no
added cost.
G.
Route hauling equipment around or away from areas of soft or yielding subgrade.
H.
Furnish and maintain earth-moving equipment in satisfactory condition and operate such
equipment as necessary to control uniform density, section, and smoothness of grade.
I.
Promptly remove soil or other foreign materials that fall on pavements.
J.
In-place density and moisture content will be determined by ASTM D2922. Cooperate with
this testing by leveling small test areas as designated.
3.2 is a Port Environmental Affairs specification for use in PDX, PIC, and Cascade Station projects.
3.2
STOCKPILING
A.
If the consistency or texture of excavated soil changes such that it no longer meets suitable
material requirements, segregate excavated unsuitable material from suitable material.
Unsuitable material shall be hauled offsite and disposed at a Port-approved disposal site.
B.
Placement of Stockpile Material:
1.
Stockpile Location:
a.
Place stockpiled materials only in a location designated by the Port.
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b.
2.
C.
Stockpiles shall be placed so that they do not impede overland flow or cause
impoundments or other surface ponding (e.g., not placed within obvious
watercourses as indicated by rivulets, embankments, or linear depressions).
c.
Ensure that no part of a stockpile is placed such that it impacts storm drains, catch
basins, streams, wetlands, or other storm water infrastructure or surface water
features.
Segregation:
a.
Use construction fencing or Port-approved alternative to delineate designated
stockpile footprint.
b.
At each entrance and exit to the stockpile location, install a sign with the project
name, name and phone number of the person responsible for managing the
stockpile, and type of material being stockpiled (e.g., topsoil or sand).
c.
Ensure that only Port-approved suitable material is placed on the stockpile.
d.
At the end of each workday, ensure that the stockpile is secure from illicit dumping
or other activities that would compromise the integrity of the stockpiled material.
Stockpile Grading:
1.
Drag, blade, or slope the grade to provide proper surface drainage that does not allow
ponding to occur anywhere on or adjacent to a stockpile.
2.
Build stockpile such that no vertical faces are created. Material shall be graded to a slope
that does not exceed the angle of repose or otherwise result in sloughing.
Include 3 for work on the airfield.
3.
Stockpile shall not exceed 5 feet in height.
D.
Erosion Control:
1.
Stockpiles shall meet erosion control requirements specified in Section 015713.
2.
If stockpile activities will cease for 30 days or more, the entire stockpile shall be
stabilized using vegetation or a heavy mulch layer, temporary seeding, or another method
that does not require germination to control erosion.
3.
Upon completion of the project and associated stockpile activities, the entire stockpile
shall be permanently stabilized with vegetation (hydroseed or approved alternative)
unless otherwise directed by the Port.
E.
Survey:
1.
Upon completion of stockpiling and grading activities, the Contractor shall contact the
Port for approval.
2.
Track all quantities and types of materials placed on each stockpile and report them to the
Port.
3.
The Port will conduct the final stockpile survey.
3.3
CLEARING AND GRUBBING
A.
Remove clearing and grubbing materials to a depth of one foot below original ground.
B.
Completely remove stumps and roots larger than 1 inch in diameter.
C.
Dispose of clearing and grubbing materials off Port property.
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D is a Port Environmental Affairs specification. Do not edit.
D.
Limit the total cleared and grubbed area excavations, and other disturbance, to only those areas
necessary for the orderly flow of work.
Use 3.4 and 3.5 together for large jobs. Use 3.6 for small jobs.
3.4
STRIPPING
A.
Strip approximately 6 inches of sod and topsoil from designated areas.
Choose between B and C.
B.
Haul stripping to the disposal area shown on the drawings.
C.
Dispose of stripping off Port property.
Choose 3.5 or 3.6. Use 3.5 for small quantity, non-earthwork projects. Use 3.6 for larger earthwork projects that include
grading, filling, etc.
3.5
COMMON EXCAVATION
A.
Excavate to the depth, lines, and grades shown on the drawings or as otherwise specified.
Choose between B and C.
B.
Haul excess common excavation to the disposal area shown on the drawings.
C.
Dispose of excess common excavation off Port property.
3.6
EXCAVATION
A.
Strip approximately 6 inches of sod and topsoil from areas that will underlay new pavement.
B.
Excavate to the depth, lines, and grades shown on the drawings or as otherwise specified.
Choose between C and D.
C.
Dispose of sod and excess common excavation off Port property.
D.
Haul sod and excess common excavation to the disposal area shown on the drawings.
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3.7
SUBGRADE AERATION
Use A if aeration is a bid item.
Tenants: Delete A.
A.
Perform only at the direction of the Port.
B.
Subgrade soils that cannot be compacted as specified, or yield under construction traffic
because of high moisture content, shall be aerated to lower the moisture content.
C.
Aerate to a minimum depth of 12 inches below subgrade.
D.
Aerate with plows, tillers, disks, or other suitable equipment.
E.
Select the number of passes of aerating equipment and duration of aerating to adjust moisture
content as needed for proper compacting of the soil.
3.8
UNSUITABLE EXCAVATION AND BACKFILLING
Tenants: Delete A.
A.
Perform only at the direction of the Port.
B.
Excavate to the depth and extent required.
C.
No wheeled or tracked equipment will be allowed to operate on the surface of the excavation.
Use only backhoe, grade-all, drag line, or equal.
D.
Remove and replace underlying soil disturbed by the Contractor’s methods of excavation or
backfilling as directed, at no added cost.
Tenants: Delete “unless otherwise directed.”
E.
Haul unsuitable material off Port property to an approved location unless otherwise directed by
the Port.
Choose between F and G.
F.
Backfill with borrow.
G.
Backfill with approved common excavation.
excavation has been used.
Use borrow only after available common
Edit as appropriate.
3.9
REMOVAL AND PLUGGING OF ABANDONED PIPES, CULVERTS, AND
MISCELLANEOUS STRUCTURES
A.
See Section 312300, Trenching, Backfilling, and Compacting.
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3.10
EMBANKMENT
A.
Construct embankment to the lines and grade shown on the drawings.
B.
Construct embankment from common excavation materials. Use borrow only after available
common excavation has been used.
C.
Construct in lifts of not more than 12 inches in loose depth. The full width of the cross section
shall be brought up uniformly.
D.
Material shall be placed in layers and shall be near optimum moisture content before rolling to
obtain the prescribed compaction. Wetting or drying of the material and manipulation to secure
a uniform moisture content throughout the layer may be required. Such an operation shall be
incidental to the appropriate bid item. Should the material be too wet to permit proper
compaction by rolling, delay work on portions of the fill thus affected until the material has
dried to an acceptable moisture content.
E.
Do not place frozen material in the embankment, or place embankment material on frozen
material.
F.
Be responsible for the stability of embankments and replace any portion which has become
displaced due to the Contractor’s improper operations.
G.
Start layers in the deepest portion of the fill, and as placement progresses, construct layers
approximately parallel to the finished grade line.
H.
Route equipment, both loaded and empty, over the full width of embankment to ensure uniform
distribution and density of material placement.
I.
Compact each lift as follows:
1.
Embankment underlying new pavement shall be compacted to a minimum of 95 percent
of AASHTO T-180.
2.
Embankment outside the limit of new pavement shall be compacted to a minimum of
92 percent of AASHTO T-180.
3.11
SITE GRADING
A.
Using common excavation materials, shape, trim, finish, and compact surface areas to conform
to the lines, grades, and cross-sections shown on the drawings or as designated by the Port.
B.
Place 4 inches of topsoil on grading areas to be seeded.
C.
Grade surfaces to drain.
D.
Eliminate wheel ruts by regrading.
E.
Compact the top 12 inches to 92 percent of maximum density as determined by AASHTO
T-180.
F.
The finished surface of site grading areas shall not be more than 0.08 foot from specified grade.
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3.12
SUBGRADE PREPARATION
A.
Shape top of subgrade to the lines and grades shown on the drawings.
B.
Maintain top of subgrade in a free-draining condition.
C.
Stockpiling materials on top of subgrade will not be permitted unless approved.
D.
Vehicles will not be allowed to travel in a single track. If ruts are formed, reshape and reroll.
Choose between E and F.
E.
No compaction of subgrade is required.
F.
Compact the top 12 inches of subgrade to a minimum of 95 percent of AASHTO T-180.
G.
The finished top of subgrade shall not vary by more than 0.05 foot from established grade and
cross-section.
3.13
SUBBASE
A.
Subgrade shall be accepted before construction of subbase course begins.
B.
Construct subbase using borrow.
Choose 1 or 2 lifts.
C.
Construct subbase in ____ approximately equal lift(s).
D.
Compact the top 12 inches to 100 percent maximum density and the remaining to 95 percent of
maximum density as determined by AASHTO T-180.
E.
The finished top of subbase course shall not vary by more than 0.05 foot from established grade
and cross-section.
3.14
RIPRAP
A.
Place loose riprap in accordance with ODOT 00390.00.
B.
Riprap backing shall be geotextile.
END OF SECTION 312000
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