02302N.pdf

REVITALIZE WATER DISTRIBUTION SYSTEM 94-0466

SECTION 02302N Page 1

SECTION 02302N

EXCAVATION, BACKFILLING, AND COMPACTING FOR UTILITIES

PART 1 GENERAL

1.1 REFERENCES

The publications listed below form a part of this specification to the extent referenced. The publications are referred to in the text by the basic designation only.

AMERICAN SOCIETY FOR TESTING AND MATERIALS (ASTM)

ASTM A 139 Electric-Fusion (ARC)-Welded Steel Pipe (NPS 4 and Over)

ASTM A 252 Welded and Seamless Steel Pipe Piles

ASTM D 698 Laboratory Compaction Characteristics of Soil Using

Standard Effort (12,400 ft-lbf/ft )

ASTM D 1557 Laboratory Compaction Characteristics of Soil Using Modified Effort (56,000 ft-lbf/ft )

ASTM D 1586 Penetration Test and Split-Barrel Sampling of Soils

ASTM D 2487 Classification of Soils for Engineering Purposes (Unified Soil

Classification System)

ASTM D 2774 Underground Installation of Thermoplastic Pressure Piping

ASTM D 4253 Maximum Index Density of Soils Using a Vibratory Table

ASTM D 4254 Minimum Index Density and Unit Weight of Soils and Calculation of Relative Density

ASTM D 4632 Grab Breaking Load and Elongation of Geotextiles

ASTM D 4759 Determining the Specification Conformance of Geosynthetics

AMERICAN WOOD-PRESERVERS' ASSOCIATION (AWPA)

AWPA C2 Lumber, Timber, Bridge Ties and Mine Ties - Preservative

Treatment by Pressure Processes

AWPA P5 Waterborne Preservatives

U.S. ARMY CORPS OF ENGINEERS (USACE)

EM 385-1-1 Safety and Health Requirements Manual

1.2 DEFINITIONS

1.2.1 Backfill

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Material used in refilling a cut, trench or other excavation.

1.2.2 Cohesive Materials

Soils classified by ASTM D 2487 as GC, SC, ML, CL, MH, and CH. Materials classified as GM and SM will be identified as cohesive only when fines have a plasticity index greater than zero.

1.2.3 Cohesionless Materials

Soils classified by ASTM D 2487 as GW, GP, SW, and SP. Materials classified as GM and SM will be identified as cohesionless only when the fines have a plasticity index of zero.

1.2.4 Compaction

The process of mechanically stabilizing a material by increasing its density at a controlled moisture condition. "Degree of Compaction" is expressed as a percentage of the maximum density obtained by the test procedure described in ASTM D 698 or ASTM D 1557 for general soil types abbreviated in this specification as " 95 percent ASTM D 1557 maximum density."

1.2.5 Granular Pipe Bedding

A dense, well-graded aggregate mixture of sand, gravel, or crushed stone (mixed individually, in combination with each other, or with suitable binder soil) placed on a subgrade to provide a suitable foundation for pipe. Granular bedding material may also consist of poorly graded sands or gravels where fast draining soil characteristics are desired.

1.2.6 Hard Material

Weathered rock, dense consolidated deposits, or conglomerate materials (excluding man made materials such as concrete) which are not included in the definition of "rock" but which usually require the use of heavy excavation equipment, ripper teeth, or jack hammers for removal. Material indicated in the soil boring logs as having a standard penetration resistance as determined by ASTM D 1586 between 60 and 600 blows per foot is arbitrarily defined herein as "Hard Material."

1.2.7 In-Situ Soil

Existing in place soil.

1.2.8 Lift

A layer (or course) of soil placed on top of subgrade or a previously prepared or placed soil in a fill or backfill.

1.2.9 Refill

Material placed in excavation to correct overcut in depth.

1.2.10 Rock

Solid homogeneous interlocking crystalline material with firmly cemented, laminated, or foliated masses or conglomerate deposits, neither of which can be removed without systematic drilling and blasting, drilling and the use of expansion jacks or feather wedges, or the use of backhoe-mounted pneumatic hole punchers or rock breakers; also large boulders, buried masonry, or concrete other than pavement exceeding 1/2 cubic yard in volume. Removal of "hard material" will not be considered rock excavation because of intermittent drilling and blasting that is performed merely to increase production.

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Material identified in the soil boring logs as having a standard penetration resistance as determined by ASTM D 1586 greater than 600 blows per foot is arbitrarily defined herein as "Rock."

1.2.11 Topsoil

In natural or undisturbed soil formations, the fine-grained, weathered material on the surface or directly below any loose or partially decomposed organic matter. Topsoil may be a dark-colored, fine, silty, or sandy material with a high content of well decomposed organic matter, often containing traces of the parent rock material. Gradation and material requirements specified herein apply to all topsoil references in this contract. The material shall be representative of productive soils in the vicinity.

1.2.12 Unyielding Material

Rock rib, ridge, rock protrusion, or soil with cobbles in the trench bottom requiring a covering of finer grain material or special bedding to avoid bridging in the pipe or conduit.

1.2.13 Unsatisfactory Material

In-Situ soil or other material which can be identified as having insufficient strength characteristics or stability to carry intended loads in the trench without excessive consolidation or loss of stability. Also backfill material which contains refuse, frozen material, large rocks, debris, soluble particles, and other material which could damage the pipe or cause the backfill not to compact. Materials classified as PT, OH, or OL by ASTM D 2487 are unsatisfactory.

1.2.14 Unstable Material

Material in the trench bottom which lacks firmness to maintain alignment and prevent joints from separating in the pipe, conduit, or appurtenance structure during backfilling. This may be material otherwise identified as satisfactory which has been disturbed or saturated.

1.3 SUBMITTALS

Government approval is required for submittals with a "G" designation; submittals not having a "G" designation are for information only or as otherwise designated. When used, a designation following the "G" designation identifies the office that will review the submittal for the Government. The following shall be submitted in accordance with Section 01330 SUBMITTAL PROCEDURES:

SD-06 Test Reports

Concrete tests

Pipe bedding material tests

Topsoil tests

Density and moisture tests

SD-07 Certificates

Shoring and sheeting plan

Dewatering plan

1.4 REGULATORY REQUIREMENTS

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Materials and workmanship specified herein with reference to NYSDOT State Standard shall be in accordance with the referenced articles, sections, and paragraphs of the standard except that contractual and payment provisions do not apply. Where the term "Engineer" is used, it shall mean the Contracting Officer. Where the term "state" is used, it shall mean "Federal Government."

1.5 DELIVERY, STORAGE, AND HANDLING

Deliver and store materials in a manner to prevent contamination, segregation, freezing, and other damage. Store synthetic fiber filter fabric to prevent exposure to direct sunlight.

1.6 CRITERIA FOR BIDDING

Base bids on the following criteria:

a. Surface elevations are as indicated.

b. No pipes or other man-made obstructions, except those indicated, will be encountered.

c. Ground water elevations indicated are those existing at the time subsurface investigations were made and do not necessarily represent ground water elevation at the time of construction.

d. Blasting will not be permitted.

1.7 PROTECTION

1.7.1 Test Pits

The Contractor shall excavate and backfill test pits in order to determine existing underground utility type, size and/or condition where existing utilities are encountered or new utility connections to existing facilities are proposed. The Contractor shall excavateand backfill test pits in a manner approved by the Base Engineer that prevents damage to wrappings, coatings or other protective coverings, such as by hand digging, vacuum excavation or similar non-destructive locating equipment. The limits of the excavation shall be those sufficient to determine existing utility type, size and/or condition.

1.7.2 Dewatering Plan

Base on site surface and subsurface conditions, available soil and hydrological data.

1.7.3 Utilities

Movement of construction machinery and equipment over pipes and utilities during construction shall be at the Contractor's risk. Excavation made with power-driven equipment is not permitted within two feet of known Government-owned utility or subsurface construction. For work immediately adjacent to or for excavations exposing a utility or other buried obstruction, excavate by hand. Start hand excavation on each side of the indicated obstruction and continue until the obstruction is uncovered or until clearance for the new grade is assured. Support uncovered lines or other existing work affected by the contract excavation until approval for backfill is granted by the Contracting Officer. Report damage to utility lines or subsurface construction immediately to the Contracting Officer.

1.8 QUALITY ASSURANCE

1.8.1 Shoring and Sheeting Plan

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Describe materials of shoring system to be used. Indicate whether or not components will remain after filling or backfilling. Provide plans, sketches, or details along with calculations by a professional engineer registered in any jurisdiction. Indicate sequence and method of installation and removal.

1.8.2 Dewatering Plan

Describe the basic components of the dewatering system proposed for use and its planned method of operation. Record performance and effectiveness of method or system in use and submit weekly.

Dewatering plan, as a minimum, shall address those requirements outlined in paragraph entitled "Drainage and Dewatering."

1.8.3 Welder's Qualifications

Submit prior to on-site welding.

1.8.4 Topsoil tests

Submit topsoil tests verifying conformance to required parameters prior to commencing seeding and sodding operations.

1.8.5 Density and moisture tests

Submit field test data not listed above sufficiently in advance of construction so as not to delay work.

Submit within 14 days of test date.

PART 2 PRODUCTS

2.1 SOIL MATERIALS

Provide soil materials as specified below free of debris, roots, wood, scrap material, vegetable matter, refuse, soft unsound particles, ice, or other deleterious and objectionable materials.

2.1.1 Backfill

Bring trenches to grade indicated on the drawings using material [excavated on the site of this project.

This material will be considered unclassified and no testing other than for compaction will be required before use as backfill

2.1.2 Special Backfill for Structures and Pavements

Backfill trenches under roads, structures, and paved areas with material conforming to NYS DOT 304-

2.02 TYPE-4

2.1.3 Topsoil Material

Salvaged topsoil from stockpile. Prior to spreading, test topsoil, and add necessary soil modifiers to bring material within the ranges specified in NYSDOT Section 713.01 Furnish additional topsoil from approved sources off the site meeting requirements specified in NYSDOT Section 713.01 if stockpiled material is insufficient to complete work indicated.

Topsoil shall be free of subsoil, stumps, rocks larger than 3/4 inch in diameter (with maximum 3 percent retained on 1/4 inch sieve), brush, weeds, toxic substances, and other material or substance detrimental to plant growth. Topsoil shall be a natural, friable soil representative of productive soils in

SECTION 02302N Page 6 the vicinity. Modify the topsoil provided if necessary to meet the requirements specified in NYSDOT Section 713.01

2.1.4 Pipe Materials Specification Soil Material Installation Reference

a. Ductile shall be gravel, Iron Pressure 02510A bedding shall be Pipe GW, GP, SW,SP.

b. Polyvinyl ASTM D 2774, except ASTM D 2774 Chloride (PVC) 02510A bedding and AWWAM23 all material sur-rounding pipe shall have maximum particle size of 1/2 inch.

Provide material for pipe bedding as indicated NYSDOT Standard Specifications conforming to Section 703-0201

2.2 FILTER FABRIC

Provide a pervious sheet of polyester, nylon, glass or polypropylene filaments woven, spun bonded, fused, or otherwise manufactured into a nonraveling fabric with uniform thickness and strength. Fabric shall have the following manufacturer certified minimum average roll properties as determined by

ASTM D 4759:

Class A Class B

a. Grab tensile strength (ASTM D 4632) min. 180 80 lbs.

machine and transversed direction

b. Grab elongation (ASTM D 4632) min. 15 15 percent machine and transverse direction

2.3 BURIED WARNING AND IDENTIFICATION TAPE

Polyethylene plastic with metallic core or metallic-faced, acid- warning tape manufactured specifically for warning and identification of buried utility lines. Provide tape on rolls, 3 inch minimum width, color coded as specified below for the intended utility with warning and identification imprinted in bold black letters continuously over the entire tape length. Warning and identification to read, "CAUTION, BURIED (intended service) LINE BELOW" or similar wording. Color and printing shall be permanent, unaffected by moisture or soil.

Warning Tape Color Codes

Yellow: Electric Yellow: Gas, Oil, Dangerous Materials Orange: Telephone and Other Communications Blue: Water Systems Green: Sewer Systems White: Steam Systems

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Gray: Compressed Air

2.4 MATERIAL FOR PIPE CASING

2.4.1 Casing Pipe

ASTM A 139, Grade B, or ASTM A 252, Grade 2, smooth wall pipe. Casing size shall be of the outside diameter and wall thickness as indicated. Protective coating is not required on casing pipe.

2.4.2 Wood Supports

Treated Yellow Pine or Douglas Fir, rough, structural grade. Provide wood with nonleaching water-borne pressure preservative (ACA or CCA) and treatment conforming to AWPA P5 and AWPA C2, respectively. Secure wood supports to carrier pipe with stainless steel or zinc-coated steel bands.

PART 3 EXECUTION

3.1 PROTECTION

3.1.1 Shoring and Sheeting

Provide shoring bracing, cribbing, trench boxes, underpinning,andsheeting where indicated. In addition to Section 25 A and B of EM 385-1-1 , include provisions in the shoring and sheeting plan that will accomplish the following:

a. Prevent undermining of pavements, foundations and slabs.

b. Prevent slippage or movement in banks or slopes adjacent to the excavation.

3.1.2 Drainage and Dewatering

Plan for and provide the structures, equipment, and construction for the collection and disposal of surface and subsurface water encountered in the course of construction.

3.1.2.1 Drainage

Surface water shall be directed away from excavation and construction sites so as to prevent erosion and undermining of foundations. Diversion ditches, dikes and grading shall be provided and maintained as necessary during construction. Excavated slopes and backfill surfaces shall be protected to prevent erosion and sloughing. Excavation shall be performed so that the site and the area immediately surrounding the site and affecting operations at the site shall be continually and effectively drained.

3.1.3 Dewatering

Groundwater flowing toward or into excavations shall be controlled to prevent sloughing of excavation slopes and walls, boils, uplift and heave in the excavation and to eliminate interference with orderly progress of construction. French drains, sumps, ditches or trenches will not be permitted within 3 feet of the foundation of any structure, except with specific written approval, and after specific contractual provisions for restoration of the foundation area have been made. Control measures shall be taken by the time the excavation reaches the water level in order to maintain the integrity of the in situ material.

While the excavation is open, the water level shall be maintained continuously, at least 3 feet below the working level.

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Operate the dewatering system until construction work below existing water levels is complete.

Measure and record the performance of the dewatering system

3.1.4 Underground Utilities

Location of the existing utilities indicated is approximate. The Contractor shall engage a firm experienced in utility location to verify and identify underground utilities and mark same in advance of the pipeleine and other related excavation work. The Contractor shall physically verify the location and elevation of the existing utilities indicated prior to starting construction. The Contractor shall scan the construction site with electromagnetic and sonic equipment and mark the surface of the ground where existing underground utilities are discovered. Any digging permits issued by the government are to be used as reference only; physical location and marking will be the responsibility of the experienced uitility location firm engaged by the Contractor.

3.1.5 Structures and Surfaces

Protect newly backfilled areas and adjacent structures, slopes, or grades from traffic, erosion settlement, or any other damage. Repair and reestablish damaged or eroded grades and slopes and restore surface construction prior to acceptance. Protect existing streams, ditches, and storm drain inlets from water-borne soil by means of straw bale dike filter fabric dams as indicated on the contract drawings. Perform work in accordance with requirements specified in Section 01356A "Stormwater Pollution Prevention Measures".

3.1.5.1 Disposal of Excavated Material

Dispose of excavated material so that it will not obstruct the flow of runoff, streams, endanger a partly finished structure, impair the efficiency or appearance of any facilities, or be detrimental to the completed work.

3.1.5.2 Interim Cleanup

Contractor to install no more than 1000 LF pipe, rough grade and seed. All pavements to be swept each day.

3.2 SURFACE PREPARATION

3.2.1 Stockpiling Topsoil

Strip suitable soil from the site where excavation or grading is indicated and stockpile separately from other excavated material. Material unsuitable for use as topsoil shall be wasted shall be stockpiled and used for backfilling. Locate topsoil so that the material can be used readily for the finished grading.

Where sufficient existing topsoil conforming to the material requirements is not available on site, provide borrow materials suitable for use as topsoil. Protect topsoil and keep in segregated piles until needed.

3.2.2 Cutting Pavement, Curbs, and Gutters

Saw cut with neat, parallel, straight lines one foot wider than trench width on each side of trenches and one foot beyond each edge of pits. When the saw cut is within 3 feet of an existing joint, remove pavement to the existing joint.

3.3 GENERAL EXCAVATION AND TRENCHING

Keep excavations free from water while construction is in progress. Notify the Contracting Officer immediately in writing if it becomes necessary to remove rock or hard, unstable, or otherwise unsatisfactory material to a depth greater than indicated. Make trench sides as nearly vertical as

SECTION 02302N Page 9 practicable except where sloping of sides is allowed. Sides of trenches shall not be sloped from the bottom of the trench up to the elevation of the top of the pipe. Excavate ledge rock, boulders, and other unyielding material to an overdepth at least 6 inches below the bottom of the pipeconduit and appurtenances unless otherwise indicated or specified. Blasting will not be permitted. Use bedding material gravel sand placed in 6 inch maximum layers to refill overdepths to the proper grade. At the Contractor's option, the excavations may be cut to an overdepth of not less than 4 inches and refilled to required grade as specified. Grade bottom of trenches accurately to provide uniform bearing and support for each section of pipe on undisturbed soil, or bedding material as indicated or specified at every point along its entire length except for portions where it is necessary to excavate for bell holes and for making proper joints. Dig bell holes and depressions for joints after trench has been graded.

Dimension of bell holes shall be as required for properly making the particular type of joint to ensure that the bell does not bear on the bottom of the excavation. Trench dimensions shall be as indicatedor specified.

3.4.1 Shoring and Sheeting

Shore and sheet excavations as described in the plan submitted with various member sizes arranged to prevent injury to persons and damage to structures. Arrange shoring and sheeting to preclude injurious caving during removal. Obtain approval from the Contracting Officer prior to removing shoring, sheeting, or bracing in excavations adjacent to on-grade slabs, foundations, or other structural elements.

3.5 BEDDING

Of materials and depths as indicatedorspecified for utility lines and utility line structures. Place bedding in 6 inch maximum loose lifts. Provide uniform and continuous support for each section of structure except at bell holes or depressions necessary for making proper joints.

3.6 BURIED WARNING AND IDENTIFICATION TAPE

Install tape in accordance with manufacturer's recommendations except as modified herein. Bury tape at the depth indicated.

3.7 BACKFILLING

Construct backfill in two operations (initial and final) as indicated and specified in this section. Place initial backfill in 6 inch maximum loose lifts to one foot above pipe unless otherwise specified. Ensure that initially placed material is tamped firmly under pipe haunches. Bring up evenly on each side and along the full length of the pipe,. Ensure that no damage is done to the utility or its protective coating.

Place the remainder of the backfill (final backfill) in 9 inch maximum loose lifts unless otherwise specified. Compact each loose lift as specified in the paragraph entitled "General Compaction" before placing the next lift. Do not backfill in freezing weather or where the material in the trench is already frozen or is muddy, except as authorized. Provide a minimum cover from final grade of 4 feet for water piping. Where settlements greater than the tolerance allowed herein for grading occur in trenches and pits due to improper compaction, excavate to the depth necessary to rectify the problem, then backfill and compact the excavation as specified herein and restore the surface to the required elevation.

Coordinate backfilling with testing of utilities. Provide buried warning and identification tape installed in accordance with the manufacturer's recommendation.

3.8 COMPACTION

Use hand-operated, plate-type, vibratory, or other suitable hand tampers in areas not accessible to larger rollers or compactors. Avoid damaging pipes and protective pipe coatings. Compact material in accordance with the following unless otherwise specified. If necessary, alter, change, or modify selected equipment or compaction methods to meet specified compaction requirements.

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3.8.1 Compaction of Material in Subcuts or Overexcavations

In rock, compact to 95 percent of ASTM D 1557 maximumASTM D 4254 relative density. In stable soils, compact to 90 percent of ASTM D 1557 maximum ASTM D 4254 relative density.

3.8.2 Compaction of Pipe and Conduit Bedding

In rock, compact to 95 percent 90 percent of ASTM D 4254 relative density.

3.8.3 Compaction of Backfill

Compact initial backfill material surrounding pipes, cables, conduits, or ducts, to 90 percent of ASTM D 4254 maximum density except where bedding and backfill are the same material. Where bedding and backfill are the same material, compact initial backfill to the density of the bedding.

3.9 CASING PIPE INSTALLATION

3.9.1 Casing Pipe

Casing pipe shall be installed using equipment approved boring methods in accordance with AWWA and ASTM standards.

3.10 FINISH OPERATIONS

3.10.1 Grading

Finish to grades indicated within one-tenth of a foot. Provide sod or topsoil in areas to be seeded or sodded as indicated. Grade areas to drain water away from structures . Grade existing grades that are to remain but have been disturbed by the Contractor's operations.

3.10.2 Spreading Topsoil

Clear areas to receive topsoil for the finished surface of materials that would interfere with planting and maintenance operations. Scarify subgrade to a depth of 2 inches. Do not place topsoil when the subgrade is frozen, extremely wet or dry, or in other conditions detrimental to seeding, planting, or grading. Spread topsoil to a uniform depth of 4 inches over the designated areas.

3.10.3 Disposition of Surplus Material

Surplus or other soil material not required or suitable for filling, backfilling, or grading shall be removed from Government property.

3.10.4 Protection of Surfaces

Protect newly graded areas from traffic, erosion, and settlements that may occur and as required in Section 01575N, "Temporary Environmental Controls." Repair or reestablish damaged grades, elevations, or slopes.

3.10.5 Pavement Repair

Repair pavement, curbs, and gutters as indicated do not repair pavement until trench or pit has been backfilled and compacted as specified herein. Provide a temporary road surface of crushed stone or over backfilled portion until permanent pavement is repaired. Remove and dispose of temporary road surface material when permanent pavement is placed. As a minimum, maintain one-way traffic on roads and streets crossed by trenches.

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3.11 FIELD QUALITY CONTROL

Test beddingbackfilltopsoil for conformance to specified requirements. Test backfill to be used under roads and paved areas for conformance to special requirements. Perform at least one of each of the required tests for each material provided. Perform sufficiently in advance of construction so as not to delay work. Provide additional tests as specified above for each change of source. Perform final tests on topsoil to ensure adjustment of parameters into the ranges specified.

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