HomeMy WebLinkAboutRenton Airport - Taxiway A - 95% Drainage Tech Specs.pdfTaxiway A Reconstruction/Rehabilitation Kimley-Horn and Associates, Inc.
Renton, WA Draft Stormwater Technical Information Report
May 2024 Page 14
Appendix D - SPECIFICATIONS
CENTURY WEST ENGINEERING D-701 Pipe for Storm Drains and Culverts - 1 of 5 MAY 2024 | #35022.008.02
Item D-701 Pipe for Storm Drains and Culverts
DESCRIPTION
701-1.1 This item shall consist of the construction of pipe culverts and storm drains in accordance with
these specifications and in reasonably close conformity with the lines and grades shown on the plans.
MATERIALS
701-2.1 Materials shall meet the requirements shown on the plans and specified below. Underground
piping and components used in drainage systems for terminal and aircraft fueling ramp drainage shall be
noncombustible and inert to fuel in accordance with National Fire Protection Association (NFPA) 415.
701-2.2 Pipe.The pipe shall be of the type called for on the plans or in the proposal and shall be in
accordance with the following appropriate requirements:
AASHTO R73 Standard Practice for Evaluation of Precast Concrete Drainage
Productions
ASTM C76 Standard Specification for Reinforced Concrete Culvert, Storm Drain,
and Sewer Pipe
ASTM C655 Standard Specification for Reinforced Concrete D-Load Culvert, Storm
Drain, and Sewer Pipe
ASTM C1433 Standard Specification for Precast Reinforced Concrete Monolithic Box
Sections for Culverts, Storm Drains, and Sewers
ASTM C1479 Standard Practice for Installation of Precast Concrete Sewer, Storm
Drain, and Culvert Pipe Using Standard Installations
ASTM C1577 Standard Specification for Precast Reinforced Concrete Monolithic Box
Sections for Culverts, Storm Drains, and Sewers Designed According to
AASHTO LRFD
ASTM C1786 Standard Specification for Segmental Precast Reinforced Concrete Box
Sections for Culverts, Storm Drains, and Sewers Designed According to
AASHTO LRFD
ASTM C1840 Standard Practice for Inspection and Acceptance of Installed Reinforced
Concrete Culvert, Storm Drain, and Storm Sewer Pipe
701-2.3 Concrete. Concrete for pipe cradles shall have a minimum compressive strength of 2000 psi at
28 days and conform to the requirements of ASTM C94.
701-2.4 Rubber gaskets. Rubber gaskets for rigid pipe shall conform to the requirements of ASTM
C443.
701-2.5 Joint mortar.Not used.
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701-2.6 Joint fillers. Not used.
701-2.7 Plastic gaskets. Not used.
701-2.8. Controlled low-strength material (CLSM).Controlled low-strength material shall conform to
the requirements of Item P-153. When CLSM is used, all joints shall have gaskets.
701-2.9 Reinforced concrete pipe (RCP). Reinforced concrete pipe shall be furnished by a plant
meeting National Precast Concrete Association Plant Certification Program or American Concrete Pipe
Association QCast Plant Certification program. RCP shall conform to the requirements of ASTM C76.
The nominal length for RCP pipe shall not be less than 8 feet.
Concrete used for casting RCP shall have a minimum compressive strength of 4000 psi. Concrete cement
shall meet the requirements of ASTM C150.
RCP shall have a minimum absorption value of 9 percent when tested according to ASTM C497, Section
7, Method A.
CONSTRUCTION METHODS
701-3.1 Excavation. The width of the pipe trench shall be sufficient to permit satisfactory jointing of the
pipe and thorough tamping of the bedding material under and around the pipe, but it shall not be less than
the external diameter of the pipe plus 12 inches on each side. The trench walls shall be approximately
vertical.
Trenching and shoring shall meet the requirements of the Washington Administration Code (WAC) 296-
155, Part N. The Contractor shall comply with all current federal, state and local rules and regulations
governing the safety of men and materials during the excavation, installation and backfilling operations.
Specifically, the Contractor shall observe that all requirements of the Occupational Safety and Health
Administration (OSHA) relating to excavations, trenching, and shoring are strictly adhered to. The width
of the trench shall be sufficient to permit satisfactorily jointing of the pipe and thorough compaction of
the bedding material under the pipe and backfill material around the pipe, but it shall not be greater than
the widths shown on the plans trench detail.
Where rock, hardpan, or other unyielding material is encountered, the Contractor shall remove it from
below the foundation grade for a depth of at least 8 inches or 1/2 inch for each foot of fill over the top of
the pipe (whichever is greater) but for no more than three-quarters of the nominal diameter of the pipe.
The excavation below grade should be filled with granular material to form a uniform foundation.
Where a firm foundation is not encountered at the grade established, due to soft, spongy, or other unstable
soil, the unstable soil shall be removed and replaced with approved granular material for the full trench
width. The ENGINEER shall determine the depth of removal necessary. The granular material shall be
compacted to provide adequate support for the pipe.
The excavation for pipes placed in embankment fill shall not be made until the embankment has been
completed to a height above the top of the pipe as shown on the plans.
701-3.2 Bedding. The bedding surface for the pipe shall provide a foundation of uniform density to
support the pipe throughout its entire length.
a. Rigid pipe. The pipe bedding shall be constructed uniformly for the full length of the pipe barrel,
as required on the plans. The maximum aggregate size shall be 1 in when the bedding thickness is less
than 6 inches, and 1-1/2 in when the bedding thickness is greater than 6 inches. Bedding shall be loosely
placed uncompacted material under the middle third of the pipe prior to placement of the pipe.
CENTURY WEST ENGINEERING D-701 Pipe for Storm Drains and Culverts - 3 of 5 MAY 2024 | #35022.008.02
701-3.3 Laying pipe. The pipe laying shall begin at the lowest point of the trench and proceed upgrade.
The lower segment of the pipe shall be in contact with the bedding throughout its full length. Bell or
groove ends of rigid pipes and outside circumferential laps of flexible pipes shall be placed facing
upgrade.
Paved or partially lined pipe shall be placed so that the longitudinal center line of the paved segment
coincides with the flow line.
Elliptical and elliptically reinforced concrete pipes shall be placed with the manufacturer’s reference lines
designating the top of the pipe within five degrees of a vertical plane through the longitudinal axis of the
pipe.
701-3.4 Joining pipe. Joints shall be made with rubber gaskets, .
a. Concrete pipe. Concrete pipe may be either bell and spigot or tongue and groove. Pipe sections at
joints shall be fully seated and the inner surfaces flush and even. Concrete pipe joints shall be sealed with
rubber gaskets meeting ASTM C443 when leak resistant joints are required.
701-3.5 Embedment and Overfill. Pipes shall be inspected before any fill material is placed; any pipes
found to be out of alignment, unduly settled, or damaged shall be removed and re-laid or replaced at the
Contractor’s expense.
701-3.5-1 Embedment Material Requirements
a. Concrete Pipe. Embedment material and compaction requirements shall be in accordance with the
applicable Type of Standard Installation (Types 1, 2, 3, or 4) per ASTM C1479. If a concrete cradle or
CLSM embedment material is used, it shall conform to the plan details.
701-3.5-2 Placement of Embedment Material
The embedment material shall be compacted in layers not exceeding 6 inches on each side of the pipe and
shall be brought up one foot above the top of the pipe or to natural ground level, whichever is greater.
Thoroughly compact the embedment material under the haunches of the pipe without displacing the pipe.
Material shall be brought up evenly on each side of the pipe for the full length of the pipe.
When the top of the pipe is above the top of the trench, the embedment material shall be compacted in
layers not exceeding 6 inches and shall be brought up evenly on each side of the pipe to one foot above
the top of the pipe. All embedment material shall be compacted to a density required under Item P-152.
Concrete cradles and flowable fills, such as controlled low strength material (CLSM) per Section P-153
may be used for embedment provided adequate flotation resistance can be achieved by restraints,
weighing, or placement technique.
It shall be the Contractor’s responsibility to protect installed pipes and culverts from damage due to
construction equipment operations. The Contractor shall be responsible for installation of any extra
strutting or backfill required to protect pipes from the construction equipment.
701-3.6 Overfill
Pipes shall be inspected before any overfill is in place. Any pipes found to be out of alignment, unduly
settled, or damaged shall be removed and replaced at the Contractor’s expense. Evaluation of any
damage to RCP shall be evaluated based on AASHTO R73.
Overfill material shall be place and compacted in layers as required to achieve compaction to at least 95
percent standard proctor per ASTM D1557 The soil shall contain no debris, organic matter, frozen
material, or stones with a diameter greater than one half the thickness of the compacted layers being
placed.
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701-3.7 Inspection Requirements
An initial post installation inspection shall be performed by the ENGINEER no sooner than 30 days after
completion of installation and final backfill. Clean or flush all lines prior to inspection.
Use a camera with lighting suitable to allow a clear picture of the entire periphery of the pipe interior.
Center the camera in the pipe both vertically and horizontally and be able to pan and tilt to a 90-degree
angle with the axis of the pipe rotating 360 degrees. Use equipment to move the camera through the pipe
that will not obstruct the camera’s view or interfere with proper documentation of the pipe’s condition.
The video image shall be clear, focused, and relatively free from roll, static, or other image distortion
qualities that would prevent the reviewer from evaluating the condition of the pipe.
Incorporate specific inspection requirements for the various types of pipes beneath the general inspection
requirements.
Reinforced concrete pipe shall be inspected, evaluated, and reported on in accordance with ASTM C1840,
“Standard Practice for Inspection and Acceptance of Installed Reinforced Concrete Culvert, Storm Drain,
and Storm Sewer Pipe.” Any issues reported shall include still photo and video documentation. The
zoom ratio shall be provided for all still or video images that document any issues of concern by the
inspection firm.
ENGINEERMETHOD OF MEASUREMENT
701-4.1 The length of pipe shall be measured in linear feet of pipe in place, completed, and accepted. It
shall be measured along the centerline of the pipe from end or inside face of structure to the end or inside
face of structure, whichever is applicable. The size of pipe shall be measured separately. All fittings shall
be included in the footage as typical pipe sections in the pipe being measured.
701-4.2. Not used.
701-4.3 The volume of concrete for pipe cradles shall be the number of cubic yards of concrete that is
completed in place and accepted.
701-4.4 The volume of rock, hardpan, or other unyielding material shall be the number of cubic yards
excavated. No payment shall be made for the cushion material placed for the bed of the pipe.
BASIS OF PAYMENT
701-5.0 These prices shall fully compensate the Contractor for furnishing all materials and for all
preparation, excavation, and installation of these materials; and for all labor, equipment, tools, and
incidentals necessary to complete the item.
701-5.1 Payment will be made at the contract unit price per linear foot for Reinforced Concrete Pipe
701-5.2 Not used.
701-5.3 Payment will be made at the contract unit price per cubic yard of concrete for pipe cradles.
701-5.4 Payment will be made at the contract unit price per cubic yard for rock, hardpan, or other
unyielding material excavation.
Payment will be made under:
Item 701-5.1 12-inch Reinforced Concrete Pipe per linear foot
Item 701-5.2 18-inch Reinforced Concrete Pipe per linear foot
CENTURY WEST ENGINEERING D-701 Pipe for Storm Drains and Culverts - 5 of 5 MAY 2024 | #35022.008.02
Item 701-5.3 Concrete for pipe cradles - per cubic yard
Item 701-5.4 Rock, hardpan, or other unyielding material excavation - per cubic yard
REFERENCES
The publications listed below form a part of this specification to the extent referenced. The publications
are referred to within the text by the basic designation only.
ASTM International (ASTM)
ASTM C76 Standard Specification for Reinforced Concrete Culvert, Storm Drain,
and Sewer Pipe
ASTM C150 Standard Specification for Portland Cement
ASTM C443 Standard Specification for Joints for Concrete Pipe and Manholes, Using
Rubber Gaskets
ASTM C506 Standard Specification for Reinforced Concrete Arch Culvert, Storm
Drain, and Sewer Pipe
ASTM C507 Standard Specification for Reinforced Concrete Elliptical Culvert, Storm
Drain and Sewer Pipe
ASTM C655 Standard Specification for Reinforced Concrete D-Load Culvert, Storm
Drain and Sewer Pipe
ASTM C990 Standard Specification for Joints for Concrete Pipe, Manholes, and
Precast Box Sections Using Preformed Flexible Joint Sealants
ASTM C1433 Standard Specification for Precast Reinforced Concrete Monolithic Box
Sections for Culverts, Storm Drains, and Sewers
ASTM D1056 Standard Specification for Flexible Cellular Materials Sponge or
Expanded Rubber
ASTM D3282 Standard Practice for Classification of Soils and Soil-Aggregate Mixtures
for Highway Construction Purposes
National Fire Protection Association (NFPA)
NFPA 415 Standard on Airport Terminal Buildings, Fueling Ramp Drainage, and
Loading Walkways
END ITEM D-701
CENTURY WEST ENGINEERING D-705 Pipe Underdrains for Airports - 1 of 6 MAY 2024|#35022.008.02
Item D-705 Pipe Underdrains for Airports
DESCRIPTION
705-1.1 This item shall consist of the construction of pipe drains in accordance with these specifications
and in reasonably close conformity with the lines and grades shown on the plans.
MATERIALS
705-2.1 General. Materials shall meet the requirements shown on the plans and specified below.
705-2.2 Pipe.The pipe shall be of the type called for on the plans or in the proposal and shall be in
accordance with the following appropriate requirements.
ASTM F758 Standard Specification for Smooth-Wall Poly (Vinyl Chloride) (PVC)
Plastic Underdrain Systems for Highway, Airport, and Similar Drainage
ASTM F794 Standard Specification for Poly (Vinyl Chloride) (PVC) Profile Gravity
Sewer Pipe & Fittings Based on Controlled Inside Diameter
ASTM F949 Standard Specification for Poly (Vinyl Chloride) (PVC) Corrugated
Sewer Pipe with a Smooth Interior and Fittings
705-2.3 Joint mortar. Pipe joint mortar shall consist of one part by volume of Portland cement and two
parts sand. The Portland cement shall conform to the requirements of ASTM C150, Type I. The sand
shall conform to the requirements of ASTM C144.
705-2.4 Elastomeric seals. Elastomeric seals shall conform to the requirements of ASTM F477.
705-2.5 Porous backfill. Porous backfill shall be free of clay, humus, or other objectionable matter, and
shall conform to the gradation in Table 1 when tested in accordance with ASTM C136.
Table 1. Gradation of Porous Backfill
Sieve Designation (square openings)Percentage by Weight Passing Sieves
Porous Material No. *
1-1/2 inch 100
1 inch 90-100
3/8 inch 25-60
No. 4 5-40
No. 8 0-20
705-2.6 Granular material. Granular material used for backfilling shall conform to the requirements of
ASTM D2321 for Class IA, IB, or II materials.
705-2.7 Filter fabric. The filter fabric shall conform to the requirements of AASHTO M288 Class 2 or
equivalent.
CENTURY WEST ENGINEERING D-705 Pipe Underdrains for Airports - 2 of 6 MAY 2024|#35022.008.02
Table 2. Fabric Properties
Fabric Property Test Method Test Requirement
Grab Tensile Strength, lbs ASTM D4632 125 min
Grab Tensile Elongation %ASTM D4632 50 min
Burst Strength, psi ASTM D3785 125 min
Trapezoid Tear Strength, lbs ASTM D4533 55 min
Puncture Strength, lbs ASTM D4833 40 min
Abrasion, lbs ASTM D4886 15 max loss
Equivalent Opening Size ASTM D4751 70-100
Permittivity sec-1 ASTM D4491 0.80
Accelerated Weathering (UV Stability)
(Strength Retained - %)
ASTM D4355
*(500 hrs exposure)70
705-2.8 Controlled low-strength material (CLSM).CLSM is not used for backfilling around
underdrains.
CONSTRUCTION METHODS
705-3.1 Equipment. All equipment required for the construction of pipe underdrains shall be on the
project, in good working condition, and approved by the Engineer before construction is permitted to
start.
705-3.2 Excavation. The width of the pipe trench shall be sufficient to permit satisfactory jointing of the
pipe and thorough tamping of the bedding material under and around the pipe but shall not be less than
the external diameter of the pipe plus 6 inches on each side of the pipe. The trench walls shall be
approximately vertical.
Where rock, hardpan, or other unyielding material is encountered, it shall be removed below the
foundation grade for a depth of at least 4 inches. The excavation below grade shall be backfilled with
selected fine compressible material, such as silty clay or loam, and lightly compacted in layers not over 6
inches in uncompacted depth to form a uniform but yielding foundation.
Where a firm foundation is not encountered at the grade established, due to soft, spongy, or other unstable
soil, the unstable soil shall be removed and replaced with approved granular material for the full trench
width. The Engineer shall determine the depth of removal necessary. The granular material shall be
compacted to provide adequate support for the pipe.
Excavated material not required or acceptable for backfill shall be disposed of by the Contractor as
directed by the Engineer. The excavation shall not be carried below the required depth; if this occurs, the
trench shall be backfilled at the Contractor’s expense with material approved by the Engineer and
compacted to the density of the surrounding material.
The pipe bedding shall be constructed uniformly over the full length of the pipe barrel, as required on the
plans. The maximum aggregate size shall be 1 inch when the bedding thickness is less than 6 inches, and
1-1/2 inch when the bedding thickness is greater than 6 inches. Bedding shall be loosely placed,
uncompacted material under the middle third of the pipe prior to placement of the pipe.
CENTURY WEST ENGINEERING D-705 Pipe Underdrains for Airports - 3 of 6 MAY 2024|#35022.008.02
The Contractor shall do trench bracing, sheathing, or shoring necessary to perform and protect the
excavation as required for safety and conformance to federal, state, and local laws. Unless otherwise
provided, the bracing, sheathing, or shoring shall be removed by the Contractor after the backfill has
reached at least 12 inches over the top of the pipe. The sheathing or shoring shall be pulled as the granular
backfill is placed and compacted to avoid any unfilled spaces between the trench wall and the backfill
material. The cost of bracing, sheathing, or shoring, and the removal of same, shall be included in the unit
price bid per foot for the pipe.
705-3.3 Laying and installing pipe.
a. PVC, fiberglass, or polyethylene pipe. PVC or polyethylene pipe shall be installed in accordance
with the requirements of ASTM D2321. Perforations shall meet the requirements of AASHTO M252 or
AASHTO M294 Class 2, unless otherwise indicated on the plans. The pipe shall be laid accurately to line
and grade.
b. All types of pipe. The upgrade end of pipelines, not terminating in a structure, shall be plugged or
capped as approved by the Engineer.
Unless otherwise shown on the plans, a 4-inch bed of granular backfill material shall be spread in the
bottom of the trench throughout the entire length under all perforated pipe underdrains.
Pipe outlets for the underdrains shall be constructed when required or shown on the plans. The pipe
shall be laid with tight-fitting joints. Porous backfill is not required around or over pipe outlets for
underdrains. All connections to other drainage pipes or structures shall be made as required and in a
satisfactory manner. If connections are not made to other pipes or structures, the outlets shall be protected
and constructed as shown on the plans.
e. Filter fabric.The filter fabric shall be installed in accordance with the manufacturer’s
recommendations, or in accordance with the AASHTO M288 Appendix, unless otherwise shown on the
plans.
705-3.4 Not Used.
705-3.5 Not Used.
705-3.6 Embedment and Backfill
a. Earth. All trenches and excavations shall be backfilled soon after the pipes are installed unless
additional protection of the pipe is directed. The embedment material shall be select material from
excavation or borrow and shall be approved by the Engineer. The select material shall be placed on each
side of the pipe out to a distance of the nominal pipe diameter and one foot over the top of the pipe and
shall be readily compacted. It shall not contain stones 3 inches or larger in size, frozen lumps, chunks of
highly plastic clay, or any other material that is objectionable to the Engineer. The material shall be
moistened or dried, as required to aid compaction. Placement of the embedment material shall not cause
displacement of the pipe. Thorough compaction under the haunches and along the sides to the top of the
pipe shall be obtained.
The embedment material shall be placed in loose layers not exceeding 6 inches in depth under and
around the pipe. Backfill material over the pipe shall be placed in lifts not exceeding 8 inches. Successive
layers shall be added and thoroughly compacted by hand and pneumatic tampers, approved by the
Engineer, until the trench is completely filled and brought to the planned elevation. Embedment and
backfilling shall be done to avoid damaging top or side of the pipe.
In embankments and other unpaved areas, the backfill shall be compacted per Item P-152 to the
density required for embankments in unpaved areas. Under paved areas, the subgrade and any backfill
shall be compacted per Item P-152 to the density required for embankments for paved areas.
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b. Granular backfill. When granular backfill is required, placement in the trench and about the pipe
shall be as shown on the plans. The granular backfill shall not contain an excessive amount of foreign
matter, nor shall soil from the sides of the trench or from the soil excavated from the trench be allowed to
filter into the granular backfill. When required by the Engineer, a template shall be used to properly place
and separate the two sizes of backfill. The backfill shall be placed in loose layers not exceeding 6 inches
in depth. The granular backfill shall be compacted by hand and pneumatic tampers to the requirements as
given for embankment. Backfilling shall be done to avoid damaging top or side pressure on the pipe. The
granular backfill shall extend to the elevation of the trench or as shown on the plans.
When perforated pipe is specified, granular backfill material shall be placed along the full length of
the pipe. The position of the granular material shall be as shown on the plans. If the original material
excavated from the trench is pervious and suitable, it shall be used in lieu of porous backfill No. 1.
If porous backfill is placed in paved or adjacent to paved areas before grading or subgrade operations
is completed, the backfill material shall be placed immediately after laying the pipe. The depth of the
granular backfill shall be not less than 12 inches, measured from the top of the underdrain. During
subsequent construction operations, a minimum depth of 12 inches of backfill shall be maintained over
the underdrains. When the underdrains are to be completed, any unsuitable material shall be removed
exposing the porous backfill. Porous backfill containing objectionable material shall be removed and
replaced with suitable material. The cost of removing and replacing any unsuitable material shall be at the
Contractor’s expense.
If a granular subbase blanket course is used which extends several feet beyond the edge of paving to
the outside edge of the underdrain trench, the granular backfill material over the underdrains shall be
placed in the trench up to an elevation of 2 inches above the bottom surface of the granular subbase
blanket course. Immediately prior to the placing of the granular subbase blanket course, the Contractor
shall blade this excess trench backfill from the top of the trench onto the adjacent subgrade where it can
be incorporated into the granular subbase blanket course. Any unsuitable material that remains over the
underdrain trench shall be removed and replaced. The subbase material shall be placed to provide clean
contact between the subbase material and the underdrain granular backfill material for the full width of
the underdrain trench.
c. Controlled low-strength material (CLSM). CLSM is not used.
705-3.7 Flexible Pipe Ring Deflection.Not used.
705-3.8Connections. When the plans call for connections to existing or proposed pipe or structures, these
connections shall be watertight and made to obtain a smooth uniform flow line throughout the drainage
system.
705-3.9 Cleaning and restoration of site. After the backfill is completed, the Contractor shall dispose of
all surplus material, soil, and rubbish from the site. Surplus soil may be deposited in embankments,
shoulders, or as directed by the Engineer. Except for paved areas of the airport, the Contractor shall
restore all disturbed areas to their original condition.
METHOD OF MEASUREMENT
705-4.1 The length of pipe shall be the number of linear feet (meters) of pipe underdrains in place,
completed, and approved; measured along the centerline of the pipe from end or inside face of structure to
the end or inside face of structure, whichever is applicable. The several classes, types, and sizes shall be
measured separately. All fittings shall be included in the footage as typical pipe sections in the pipeline
being measured.
705-4.2 The quantity of porous backfill shall be the number of cubic yards of porous backfill No. 1 and
No. 2, complete in place and accepted, and shall be determined from the dimensions given on the plans by
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typical trench sections indicating the placement of porous backfill or dimensions directed by the
Engineer.
705-4.3 The quantity of filter fabric shall be the number of square yards of filter fabric in place,
completed, and approved; and shall be determined from the dimensions given on the plans by typical
trench sections indicating the placement of filter fabric or dimensions directed by the Engineer.
705-4.4. The quantity of pipe underdrains shall be made at the contract unit price per linear foot complete,
including porous backfill and filter fabric.
BASIS OF PAYMENT
705-5.1 Payment will be made at the contract unit price per linear foot for pipe underdrains of the type,
class, and size designated.
705-5.2 Not Used.705-5.3. Not Used.
705-5.4 Pipe underdrains, Complete.Pipe underdrains, complete (including porous
backfill and filter fabric) shall be made at the contract unit price per linear foot complete (including
porous backfill and filter fabric.
These prices shall be full compensation for furnishing all materials and for all preparation, excavation,
and installation of these materials, and for all labor, equipment, tools, and incidentals necessary to
complete the item.
Payment will be made under:
Item D-705-5.4 6-inch pipe per linear foot complete, including porous backfill and filter
fabric
REFERENCES
The publications listed below form a part of this specification to the extent referenced. The publications
are referred to within the text by the basic designation only.
ASTM International (ASTM)
ASTM C136 Standard Test Method for Sieve or Screen Analysis of Fine and Coarse
Aggregates
ASTM F477 Standard Specification for Elastomeric Seals (Gaskets) for Joining
Plastic Pipe
ASTM F758 Standard Specification for Smooth Wall Poly (Vinyl Chloride) (PVC)
Plastic Underdrain Systems for Highway, Airport, and Similar Drainage
ASTM F794 Standard Specification for Poly (Vinyl Chloride) (PVC) Profile Gravity
Sewer Pipe & Fittings Based on Controlled Inside Diameter
ASTM F949 Standard Specification for Poly (Vinyl Chloride) (PVC) Corrugated
Sewer Pipe with a Smooth Interior and Fittings
American Association of State Highway and Transportation Officials (AASHTO)
AASHTO M252 Standard Specification for Corrugated Polyethylene Drainage Pipe
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AASHTO M288 Standard Specification for Geotextile Specification for Highway
Applications
AASHTO M294 Standard Specification for Corrugated Polyethylene Pipe, 300- to 1500-
mm (12- to 60-in.) Diameter
AASHTO M304 Standard Specification for Poly (Vinyl Chloride) (PVC) Profile Wall
Drain Pipe and Fittings Based on Controlled Inside Diameter
END OF ITEM D-705
CENTURY WEST ENGINEERING D-751 Manholes, Catch Basins, Inlets and Inspection Holes - 1 of 6 MAY 2024 | #35022.008.02
Item D-751 Manholes, Catch Basins, Inlets and Inspection Holes
DESCRIPTION
751-1.1 This item shall consist of construction of manholes, catch basins, inlets, and inspection holes, in
accordance with these specifications, at the specified locations and conforming to the lines, grades, and
dimensions shown on the plans or required by the Engineer.
MATERIALS
751-2.1 Not Used.
751-2.2 Mortar. Mortar shall consist of one part Portland cement and two parts sand. The cement shall
conform to the requirements of ASTM C150, Type I. The sand shall conform to the requirements of
ASTM C144.
751-2.3 Concrete. Plain and reinforced concrete used in structures, connections of pipes with structures,
and the support of structures or frames shall conform to the requirements of Item P-610.
751-2.4 Precast concrete pipe manhole rings. Precast concrete pipe manhole rings shall conform to the
requirements of ASTM C478. Unless otherwise specified, the risers and offset cone sections shall have an
inside diameter of not less than 36 inches nor more than 48 inches . There shall be a gasket between
individual sections and sections cemented together with mortar on the inside of the manhole. Gaskets
shall conform to the requirements of ASTM C443.
751-2.5 Corrugated metal. Corrugated metal shall conform to the requirements of American Association
of State Highway and Transportation Officials (AASHTO) M36.
751-2.6 Frames, covers, and grates. The castings shall conform to one of the following requirements:
a. ASTM A48, Class 35B: Gray iron castings
b. ASTM A47: Malleable iron castings
c.ASTM A27: Steel castings
d.ASTM A283, Grade D: Structural steel for grates and frames
e. ASTM A536, Grade 65-45-12: Ductile iron castings
f.ASTM A897: Austempered ductile iron castings
All castings or structural steel units shall conform to the dimensions shown on the plans and shall be
designed to support the loadings, aircraft gear configuration and/or direct loading, specified.
Each frame and cover or grate unit shall be provided with fastening members to prevent it from being
dislodged by traffic, but which will allow easy removal for access to the structure.
All castings shall be thoroughly cleaned. After fabrication, structural steel units shall be galvanized to
meet the requirements of ASTM A123.
751-2.7 Steps. The steps or ladder bars shall be gray or malleable cast iron or galvanized steel. The steps
shall be the size, length, and shape shown on the plans and those steps that are not galvanized shall be
given a coat of asphalt paint, when directed.
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751-2.8 Precast inlet structures. Manufactured in accordance with and conforming to ASTM C913.
CONSTRUCTION METHODS
751-3.1 Unclassified excavation.
a. The Contractor shall excavate for structures and footings to the lines and grades or elevations,
shown on the plans, or as staked by the Engineer. The excavation shall be of sufficient size to permit the
placing of the full width and length of the structure or structure footings shown. The elevations of the
bottoms of footings, as shown on the plans, shall be considered as approximately only; and the Engineer
may direct, in writing, changes in dimensions or elevations of footings necessary for a satisfactory
foundation.
b. Boulders, logs, or any other objectionable material encountered in excavation shall be removed.
All rock or other hard foundation material shall be cleaned of all loose material and cut to a firm surface
either level, stepped, or serrated, as directed by the Engineer. All seams or crevices shall be cleaned out
and grouted. All loose and disintegrated rock and thin strata shall be removed. Where concrete will rest
on a surface other than rock, the bottom of the excavation shall not be disturbed and excavation to final
grade shall not be made until immediately before the concrete or reinforcing is placed.
c. The Contractor shall do all bracing, sheathing, or shoring necessary to implement and protect the
excavation and the structure as required for safety or conformance to governing laws. The cost of bracing,
sheathing, or shoring shall be included in the unit price bid for the structure.
d. All bracing, sheathing, or shoring involved in the construction of this item shall be removed by the
Contractor after the completion of the structure. Removal shall not disturb or damage finished masonry.
The cost of removal shall be included in the unit price bid for the structure.
e. After excavation is completed for each structure, the Contractor shall notify the Engineer. No
concrete or reinforcing steel shall be placed until the Engineer has approved the depth of the excavation
and the character of the foundation material.
751-3.2 Brick structures.
a. Foundations. A prepared foundation shall be placed for all brick structures after the foundation
excavation is completed and accepted. Unless otherwise specified, the base shall consist of reinforced
concrete mixed, prepared, and placed in accordance with the requirements of Item P-610.
b. Laying brick. All brick shall be clean and thoroughly wet before laying so that they will not
absorb any appreciable amount of additional water at the time they are laid. All brick shall be laid in
freshly made mortar. Mortar not used within 45 minutes after water has been added shall be discarded.
Retempering of mortar shall not be permitted. An ample layer of mortar shall be spread on the beds and a
shallow furrow shall be made in it that can be readily closed by the laying of the brick. All bed and head
joints shall be filled solid with mortar. End joints of stretchers and side or cross joints of headers shall be
fully buttered with mortar and a shoved joint made to squeeze out mortar at the top of the joint. Any
bricks that may be loosened after the mortar has taken its set, shall be removed, cleaned, and re-laid with
fresh mortar. No broken or chipped brick shall be used in the face, and no spalls or bats shall be used
except where necessary to shape around irregular openings or edges; in which case, full bricks shall be
placed at ends or corners where possible, and the bats shall be used in the interior of the course. In making
closures, no piece of brick shorter than the width of a whole brick shall be used; and wherever practicable,
whole brick shall be used and laid as headers.
c. Joints. All joints shall be filled with mortar at every course. Exterior faces shall be laid up in
advance of backing. Exterior faces shall be plastered or parged with a coat of mortar not less than 3/8 inch
thick before the backing is laid up. Prior to parging, all joints on the back of face courses shall be cut
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flush. Unless otherwise noted, joints shall be not less than 1/4 inch nor more than 1/2 inch wide and the
selected joint width shall be maintained uniform throughout the work.
d. Pointing. Face joints shall be neatly struck, using the weather-struck joint. All joints shall be
finished properly as the laying of the brick progresses. When nails or line pins are used, the holes shall be
immediately plugged with mortar and pointed when the nail or pin is removed.
e. Cleaning. Upon completion of the work all exterior surfaces shall be thoroughly cleaned by
scrubbing and washing with water. If necessary to produce satisfactory results, cleaning shall be done
with a 5% solution of muriatic acid which shall then be rinsed off with liberal quantities of water.
f. Curing and cold weather protection. The brick masonry shall be protected and kept moist for at
least 48 hours after laying the brick. Brick masonry work or pointing shall not be done when there is frost
on the brick or when the air temperature is below 50°F unless the Contractor has, on the project ready to
use, suitable covering and artificial heating devices necessary to keep the atmosphere surrounding the
masonry at a temperature of not less than 60°F for the duration of the curing period.
751-3.3 Concrete structures. Concrete structures which are to be cast-in-place within the project
boundaries shall be built on prepared foundations, conforming to the dimensions and shape indicated on
the plans. The construction shall conform to the requirements specified in Item P-610. Any reinforcement
required shall be placed as indicated on the plans and shall be approved by the Engineer before the
concrete is placed.
All invert channels shall be constructed and shaped accurately to be smooth, uniform, and cause
minimum resistance to flowing water. The interior bottom shall be sloped to the outlet.
751-3.4 Precast concrete structures. Precast concrete structures shall be furnished by a plant meeting
National Precast Concrete Association Plant Certification Program or another Engineer approved third
party certification program.
Precast concrete structures shall conform to ASTM C478. Precast concrete structures shall be constructed
on prepared or previously placed slab foundations conforming to the dimensions and locations shown on
the plans. All precast concrete sections necessary to build a completed structure shall be furnished. The
different sections shall fit together readily. Joints between precast concrete risers and tops shall be full
bedded in cement mortar and shall: (1) be smoothed to a uniform surface on both interior and exterior of
the structure or (2) utilize a rubber gasket per ASTM C443. The top of the upper precast concrete section
shall be suitably formed and dimensioned to receive the metal frame and cover or grate as required.
Provision shall be made for any connections for lateral pipe, including drops and leads that may be
installed in the structure. The flow lines shall be smooth, uniform, and cause minimum resistance to flow.
The metal or metal encapsulated steps that are embedded or built into the side walls shall be aligned and
placed in accordance with ASTM C478. When a metal ladder replaces the steps, it shall be securely
fastened into position.
751-3.5 Corrugated metal structures. Corrugated metal structures shall be prefabricated. All standard
or special fittings shall be furnished to provide pipe connections or branches with the correct dimensions
and of sufficient length to accommodate connecting bands. The fittings shall be welded in place to the
metal structures. The top of the metal structure shall be designed so that either a concrete slab or metal
collar may be attached to allow the fastening of a standard metal frame and grate or cover. Steps or
ladders shall be furnished as shown on the plans. Corrugated metal structures shall be constructed on
prepared foundations, conforming to the dimensions and locations as shown on the plans. When
indicated, the structures shall be placed on a reinforced concrete base.
751-3.6 Inlet and outlet pipes. Inlet and outlet pipes shall extend through the walls of the structures a
sufficient distance beyond the outside surface to allow for connections. They shall be cut off flush with
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the wall on the inside surface of the structure, unless otherwise directed. For concrete or brick structures,
mortar shall be placed around these pipes to form a tight, neat connection.
751-3.7 Placement and treatment of castings, frames, and fittings. All castings, frames, and fittings
shall be placed in the positions indicated on the plans or as directed by the Engineer and shall be set true
to line and elevation. If frames or fittings are to be set in concrete or cement mortar, all anchors or bolts
shall be in place before the concrete or mortar is placed. The unit shall not be disturbed until the mortar or
concrete has set.
When frames or fittings are placed on previously constructed masonry, the bearing surface of the masonry
shall be brought true to line and grade and shall present an even bearing surface so the entire face or back
of the unit will come in contact with the masonry. The unit shall be set in mortar beds and anchored to the
masonry as indicated on the plans or as directed by the Engineer. All units shall set firm and secure.
After the frames or fittings have been set in final position, the concrete or mortar shall be allowed to
harden for seven (7) days before the grates or covers are placed and fastened down.
When structures are located within the runway safety area, POFA, RPZ, etc., the elevation of the
structures shall be set to meet the grading requirements of these areas. Structures shall not exceed 3
inches above the elevation the surrounding areas.
751-3.8 Installation of steps. The steps shall be installed as indicated on the plans or as directed by the
Engineer. When the steps are to be set in concrete, they shall be placed and secured in position before the
concrete is placed. When the steps are installed in brick masonry, they shall be placed as the masonry is
being built. The steps shall not be disturbed or used until the concrete or mortar has hardened for at least
seven (7) days. After seven (7) days, the steps shall be cleaned and painted, unless they have been
galvanized.
When steps are required with precast concrete structures, they shall meet the requirements of ASTM
C478. The steps shall be cast into the side of the sections at the time the sections are manufactured or set
in place after the structure is erected by drilling holes in the concrete and cementing the steps in place.
When steps are required with corrugated metal structures, they shall be welded into aligned position at a
vertical spacing of 12 inches.
Instead of steps, prefabricated ladders may be installed. For brick or concrete structures, the ladder shall
be held in place by grouting the supports in drilled holes. For metal structures, the ladder shall be secured
by welding the top support to the structure and grouting the bottom support into drilled holes in the
foundation or as directed by the Engineer.
751-3.9 Backfilling.
a. After a structure has been completed, the area around it shall be backfilled with approved material,
in horizontal layers not to exceed 8 inches in loose depth and compacted to the density required in Item P-
152. Each layer shall be deposited evenly around the structure to approximately the same elevation. The
top of the fill shall meet the elevation shown on the plans or as directed by the Engineer.
b. Backfill shall not be placed against any structure until approved by the Engineer. For concrete
structures, approval shall not be given until the concrete has been in place seven (7) days, or until tests
establish that the concrete has attained sufficient strength to withstand any pressure created by the backfill
and placing methods.
c. Backfill shall not be measured for direct payment. Performance of this work shall be considered an
obligation of the Contractor covered under the contract unit price for the structure involved.
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751-3.10 Cleaning and restoration of site. After the backfill is completed, the Contractor shall dispose
of all surplus material, dirt, and rubbish from the site. Surplus dirt may be deposited in embankments,
shoulders, or as approved by the Engineer. The Contractor shall restore all disturbed areas to their original
condition. The Contractor shall remove all tools and equipment, leaving the entire site free, clear, and in
good condition.
METHOD OF MEASUREMENT
751-4.1 Manholes, catch basins, inlets, and inspection holes shall be measured by the unit.
BASIS OF PAYMENT
751-5.1 The accepted quantities of manholes, catch basins, inlets, and inspection holes will be paid for at
the contract unit price per each in place when completed. This price shall be full compensation for
furnishing all materials and for all preparation, excavation, backfilling and placing of the materials;
furnishing and installation of such specials and connections to pipes and other structures as may be
required to complete the item as shown on the plans; and for all labor equipment, tools and incidentals
necessary to complete the structure.
Payment will be made under:
Item D-751-5.1 Manholes - per each
Item D-751-5.2 Catch Basins - per each
REFERENCES
The publications listed below form a part of this specification to the extent referenced. The publications
are referred to within the text by the basic designation only.
ASTM International
ASTM A27 Standard Specification for Steel Castings, Carbon, for General
Application
ASTM A47 Standard Specification for Ferritic Malleable Iron Castings
ASTM A48 Standard Specification for Gray Iron Castings
ASTM A123 Standard Specification for Zinc (Hot-Dip Galvanized) Coatings on Iron
and Steel Products
ASTM A283 Standard Specification for Low and Intermediate Tensile Strength
Carbon Steel Plates
ASTM A536 Standard Specification for Ductile Iron Castings
ASTM A897 Standard Specification for Austempered Ductile Iron Castings
ASTM C32 Standard Specification for Sewer and Manhole Brick (Made from Clay
or Shale)
ASTM C144 Standard Specification for Aggregate for Masonry Mortar
ASTM C150 Standard Specification for Portland Cement
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ASTM C443 Standard Specification for Joints for Concrete Pipe and Manholes, Using
Rubber Gaskets.
ASTM C478 Standard Specification for Precast Reinforced Concrete Manhole
Sections
ASTM C913 Standard Specification for Precast Concrete Water and Wastewater
Structures.
American Association of State Highway and Transportation Officials (AASHTO)
AASHTO M36 Standard Specification for Corrugated Steel Pipe, Metallic-Coated, for
Sewers and Drains
END OF ITEM D-751