Amendment 5 - Spec 31 00 00 - Spoils edits and Boring Logs.pdf

West Apron Repair Project, Hill AFB 2324

SECTION TABLE OF CONTENTS

DIVISION 31 - EARTHWORK

SECTION 31 00 00

EARTHWORK

08/08

PART 1 GENERAL

1.1 CRITERIA FOR BIDDING

1.2 CRITERIA FOR BIDDING

1.3 REFERENCES

1.4 DEFINITIONS

1.4.1 Satisfactory Materials

1.4.2 Unsatisfactory Materials

1.4.3 Cohesionless and Cohesive Materials

1.4.4 Degree of Compaction

1.4.5 Hard/Unyielding Materials

1.4.6 Rock

1.4.7 Unstable Material

1.4.8 Select Granular Material

1.4.8.1 General Requirements

1.4.9 Initial Backfill Material

1.4.10 Controlled Low Strength Material

1.5 SUBSURFACE DATA

1.5.1 Classification of Excavation

1.5.2 Blasting

1.5.3 Dewatering Work Plan

1.6 SUBMITTALS

PART 2 PRODUCTS

2.1 REQUIREMENTS FOR OFFSITE SOILS

2.2 BURIED WARNING AND IDENTIFICATION TAPE

2.2.1 Warning Tape for Metallic Piping

2.2.2 Detectable Warning Tape for Non-Metallic Piping

2.3 DETECTION WIRE FOR NON-METALLIC PIPING

2.4 BRIDGING MATERIAL

2.5 CONTROLLED LOW STRENGTH MATERIAL

PART 3 EXECUTION

3.1 GENERAL EXCAVATION

3.1.1 Ditches, Gutters, and Channel Changes

3.1.2 Drainage Structures

3.1.3 Drainage

3.1.4 Dewatering

3.1.5 Trench Excavation Requirements

3.1.5.1 Bottom Preparation

3.1.5.2 Removal of Unyielding Material

3.1.5.3 Removal of Unstable Material

3.1.5.4 Excavation for Appurtenances

3.1.5.5 Jacking, Boring, and Tunneling

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3.1.6 Underground Utilities

3.1.7 Structural Excavation

3.2 OPENING AND DRAINAGE OF EXCAVATION AND BORROW PITS

3.3 STOCKPILING AREAS

3.4 FINAL GRADE OF SURFACES TO SUPPORT CONCRETE

3.5 GROUND SURFACE PREPARATION

3.5.1 General Requirements

3.5.2 Frozen Material

3.6 UTILIZATION OF EXCAVATED MATERIALS

3.7 BURIED TAPE AND DETECTION WIRE

3.7.1 Buried Warning and Identification Tape

3.7.2 Buried Detection Wire

3.8 BACKFILLING AND COMPACTION

3.8.1 Trench Backfill

3.8.1.1 Replacement of Unyielding Material

3.8.1.2 Replacement of Unstable Material

3.8.1.3 Bedding and Initial Backfill

3.8.1.3.1 Class I

3.8.1.3.2 Class II

3.8.1.3.3 Gravel and Crushed Stone

3.8.1.4 Final Backfill

3.8.2 Backfill for Appurtenances

3.9 SPECIAL REQUIREMENTS

3.9.1 Gas Distribution

3.9.2 Water Lines

3.9.3 Heat Distribution System

3.9.4 Electrical Distribution System

3.10 SUBGRADE PREPARATION

3.10.1 Construction

3.10.2 Compaction

3.11 FINISHING

3.11.1 Subgrade

3.11.2 Grading Around Structures

3.12 TESTING

3.12.1 Fill and Backfill Material Gradation

3.12.2 In-Place Densities

3.12.3 Check Tests on In-Place Densities

3.12.4 Moisture Contents

3.12.5 Optimum Moisture and Laboratory Maximum Density

3.12.6 Tolerance Tests for Subgrades

3.12.7 Controlled Strength Material

3.13 DISPOSITION OF SURPLUS MATERIAL

-- End of Section Table of Contents --

SECTION 31 00 00 Page 2 Amendment 0005

SECTION 31 00 00

EARTHWORK

08/08

PART 1 GENERAL

1.1 CRITERIA FOR BIDDING

Base bids on the following criteria:

a. Surface elevations are as indicated.

b. Pipes or other artificial obstructions, except those indicated, will not be encountered.

c. Ground water will not be encountered during excavation activities. Perched water conditions may be encountered during excavations following rainy periods. No additional compensation shall be forthcoming for any necessary groundwater (perched or otherwise) control or dewatering operations.

d. Subsurface conditions anticipated at the site are as described in paragraph SUBSURFACE DATA.

1.2 CRITERIA FOR BIDDING

Base bids on the following criteria:

a. Surface elevations are as indicated.

b. Pipes or other artificial obstructions, except those indicated, will not be encountered.

c. Ground water elevations indicated by the boring log were those existing at the time subsurface investigations were made and do not necessarily represent ground water elevation at the time of construction. Perched water conditions may be encountered during excavations following rainy periods. No additional compensation shall be forthcoming for any necessary groundwater (perched or otherwise) control or dewatering operations.

d. Subsurface conditions anticipated at the site are as described in the geotechnical data file appended/attached to these Specifications.

1.3 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.

AMERICAN ASSOCIATION OF STATE HIGHWAY AND TRANSPORTATION OFFICIALS

(AASHTO)

AASHTO T 180 (2017) Standard Method of Test for Moisture-Density Relations of Soils Using a 4.54-kg (10-lb) Rammer and a 457-mm

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(18-in.) Drop

AASHTO T 224 (2010) Standard Method of Test for Correction for Coarse Particles in the Soil Compaction Test

AMERICAN CONCRETE INSTITUTE (ACI)

ACI 229R (2013) Report on Controlled Low-Strength Materials

AMERICAN WATER WORKS ASSOCIATION (AWWA)

AWWA C600 (2017) Installation of Ductile-Iron Mains and Their Appurtenances

AMERICAN WELDING SOCIETY (AWS)

AWS D1.1/D1.1M (2015; Errata 1 2015; Errata 2 2016) Structural Welding Code - Steel

AMERICAN WOOD PROTECTION ASSOCIATION (AWPA)

AWPA P5 (2015) Standard for Waterborne Preservatives

ASTM INTERNATIONAL (ASTM)

ASTM A139/A139M (2016) Standard Specification for Electric-Fusion (ARC)-Welded Steel Pipe (NPS 4 and over)

ASTM A252 (2010) Standard Specification for Welded and Seamless Steel Pipe Piles

ASTM C136/C136M (2014) Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates

ASTM C33/C33M (2018) Standard Specification for Concrete Aggregates

ASTM D1140 (2017) Standard Test Methods for Determining the Amount of Material Finer than 75-µm (No. 200) Sieve in Soils by Washing

ASTM D1556/D1556M (2015; E 2016) Standard Test Method for Density and Unit Weight of Soil in Place by Sand-Cone Method

ASTM D1557 (2012; E 2015) Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Modified Effort (56,000 ft-lbf/ft3) (2700 kN-m/m3)

ASTM D1883 (2016) Standard Test Method for California Bearing Ratio (CBR) of Laboratory-Compacted Soils

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ASTM D2167 (2015) Density and Unit Weight of Soil in Place by the Rubber Balloon Method

ASTM D2216 (2019) Standard Test Methods for Laboratory Determination of Water (Moisture) Content of Soil and Rock by Mass

ASTM D2434 (1968; R 2006) Permeability of Granular Soils (Constant Head)

ASTM D2487 (2017) Standard Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System)

ASTM D2937 (2017; E 2017; E 2018) Standard Test Method for Density of Soil in Place by the Drive-Cylinder Method

ASTM D4318 (2017; E 2018) Standard Test Methods for Liquid Limit, Plastic Limit, and Plasticity Index of Soils

ASTM D4643 (2017) Standard Test Method for Determination of Water Content of Soil and Rock by Microwave Oven Heating

ASTM D4832 (2010) Preparation and Testing of Controlled Low Strength Material (CLSM) Test Cylinders

ASTM D4959 (2016) Determination of Water (Moisture) Content of Soil by Direct Heating

ASTM D5084 (2016a) Standard Test Methods for Measurement of Hydraulic Conductivity of Saturated Porous Materials Using a Flexible Wall Permeameter

ASTM D6938 (2017a) Standard Test Method for In-Place Density and Water Content of Soil and Soil-Aggregate by Nuclear Methods (Shallow Depth)

U.S. ARMY CORPS OF ENGINEERS (USACE)

EM 385-1-1 (2014) Safety and Health Requirements Manual

U.S. ENVIRONMENTAL PROTECTION AGENCY (EPA)

EPA 600/4-79/020 (1983) Methods for Chemical Analysis of Water and Wastes

EPA SW-846.3-3 (1999, Third Edition, Update III-A) Test Methods for Evaluating Solid Waste:

Physical/Chemical Methods

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U.S. GENERAL SERVICES ADMINISTRATION (GSA)

CID A-A-203 (Rev C; Notice 3) Paper, Kraft, Untreated

1.4 DEFINITIONS

1.4.1 Satisfactory Materials

Satisfactory materials comprise any materials classified by ASTM D2487 as GW, GP, GM, GP-GM, GW-GM, GC, GP-GC, GM-GC, SW, SP, SM,SC,CL, ML, or any combination thereof. Satisfactory materials for general open-field grading comprise the preceding plus CH in-situ and stones less than 6 inches in any dimension.

1.4.2 Unsatisfactory Materials

Materials which do not comply with the requirements for satisfactory materials are unsatisfactory. Unsatisfactory materials also include man-made fills; trash; refuse; backfills from previous construction; and material classified as satisfactory which contains root and other organic matter or frozen material. Notify the Contracting Officer when encountering any contaminated materials.

1.4.3 Cohesionless and Cohesive Materials

Cohesionless materials include materials classified in ASTM D2487 as GW, GP, SW, and SP. Cohesive materials include materials classified as GC, SC, ML, CL, MH, and CH. Materials classified as GM and SM will be identified as cohesionless only when the fines are nonplastic. Perform testing, required for classifying materials, in accordance with ASTM D4318, ASTM C136/C136M and ASTM D1140.

1.4.4 Degree of Compaction

Degree of compaction required, except as noted in the second sentence, is expressed as a percentage of the maximum density obtained by the test procedure presented in ASTM D1557 abbreviated as a percent of laboratory maximum density. Since ASTM D1557 applies only to soils that have 30 percent or less by weight of their particles retained on the 3/4 inch sieve, express the degree of compaction for material having more than 30 percent by weight of their particles retained on the 3/4 inch sieve as a percentage of the maximum density in accordance with AASHTO T 180 and corrected with AASHTO T 224 . To maintain the same percentage of coarse material, use the "remove and replace" procedure as described in NOTE 8 of Paragraph 7.2 in AASHTO T 180 .

1.4.5 Hard/Unyielding Materials

Hard/Unyielding materials comprise large cobbles and boulders, dense consolidated deposits, cemented 'caliche', or conglomerate materials which are not included in the definition of "rock". These materials usually require the use of heavy excavation equipment or possibly jack hammers for removal.

1.4.6 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

SECTION 31 00 00 Page 6 Amendment 0005 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.

1.4.7 Unstable Material

Unstable materials are those soil materials that rut and shove under the weight of construction equipment or during proof rolling operations.

Unstable materials generally have water contents of 5 or more percent over optimum, but this percentage can be lower if equipment is too heavy or used inappropriately..

1.4.8 Select Granular Material

1.4.8.1 General Requirements

Select granular material consist of materials classified as GW, GP, SW, SP, or any combination thereof by ASTM D2487 where indicated. The liquid limit of such material must not exceed 35percent when tested in accordance with ASTM D4318. The plasticity index must not be greater than 12 percent when tested in accordance with ASTM D4318. Not more than 25 percent by weight shall be retained on a 1-inch sieve, and not more than 35 percent by weight may be finer than No. 200 sieve when tested in accordance with

ASTM D1140.

1.4.9 Initial Backfill Material

Initial backfill consists of select granular material or satisfactory materials free from rocks 3 inches or larger in any dimension or free from rocks of such size as recommended by the pipe manufacturer, whichever is smaller. When the pipe is coated or wrapped for corrosion protection, free the initial backfill material of stones larger than 3 inches in any dimension or as recommended by the pipe manufacturer, whichever is smaller.

1.4.10 Controlled Low Strength Material

Controlled Low Strength Material (CLSM) shall be as defined in ACI 229R and shall met the requirements specified in PART 2 PRODUCTS.

1.5 SUBSURFACE DATA

Subsurface soil exploration data are appended to the specifications.

These data were obtained from 2018 borings performed for Repair West Apro, Facility 5000. These data represent the best subsurface information available; however, variations may exist in the subsurface between boring locations.

1.5.1 Classification of Excavation

No consideration will be given to the nature of the materials, and all excavation will be designated as unclassified excavation.

1.5.2 Blasting

Blasting will not be permitted.

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1.5.3 Dewatering Work Plan

Submit procedures for accomplishing any neccessary dewatering work.

1.6 SUBMITTALS

Government approval is required for submittals with a "G" designation;

submittals not having a "G" designation are for information only. When used, a designation following the "G" designation identifies the office that will review the submittal for the Government. Submit the following in accordance with Section 01 33 00 SUBMITTAL PROCEDURES:

SD-01 Preconstruction Submittals

Dewatering Work Plan; G Submit 15 days prior to starting work.

SD-03 Product Data

Utilization of Excavated Materials; G Procedure and location for disposal of unused satisfactory material. Notification of encountering rock in the project.

Advance notice on shoulder construction for rigid pavements.

Controlled Low Strength Material; G

SD-06 Test Reports

Testing

Borrow Site Testing

Within 24 hours of conclusion of physical tests, submit a minimum of 3 copies of test results, including calibration curves and results of calibration tests.

SD-07 Certificates

Testing Qualifications of the Corps validated commercial testing laboratory or the Contractor's validated testing facilities.

PART 2 PRODUCTS

2.1 REQUIREMENTS FOR OFFSITE SOILS

Test offsite soils brought in for use as backfill for Total Petroleum Hydrocarbons (TPH), Benzene, Toluene, Ethyl Benzene, and Xylene (BTEX) and full Toxicity Characteristic Leaching Procedure (TCLP) including ignitability, corrosivity and reactivity. Backfill shall contain a maximum of 100 parts per million (ppm) of total petroleum hydrocarbons (TPH) and a maximum of 10 ppm of the sum of Benzene, Toluene, Ethyl Benzene, and Xylene (BTEX) and shall pass the TCPL test. Determine TPH concentrations by using EPA 600/4-79/020 Method 418.1. Determine BTEX concentrations by using EPA SW-846.3-3 Method 5030/8020. Perform TCLP in accordance with EPA SW-846.3-3 Method 1311. Provide Borrow Site Testing for TPH, BTEX and TCLP from a composite sample of material from the borrow site, with at least one test from each borrow site. Do not bring material onsite until tests have been approved by the Contracting Officer.

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2.2 BURIED WARNING AND IDENTIFICATION TAPE

Provide polyethylene plastic and metallic core or metallic-faced, acid-and alkali-resistant, polyethylene plastic warning tape manufactured specifically for warning and identification of buried utility lines.

Provide tape on rolls, 3 inches 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. Provide permanent color and printing, unaffected by moisture or soil.

Warning Tape Color Codes

Red Electric

Yellow Gas, Oil; Dangerous Materials

Orange Telephone and Other Communications

Blue Water Systems

Green Sewer Systems

White Steam Systems

Gray Compressed Air

2.2.1 Warning Tape for Metallic Piping

Provide acid and alkali-resistant polyethylene plastic tape conforming to the width, color, and printing requirements specified above, with a minimum thickness of 0.003 inch and a minimum strength of 1500 psi lengthwise, and 1250 psi crosswise, with a maximum 350 percent elongation.

2.2.2 Detectable Warning Tape for Non-Metallic Piping

Provide polyethylene plastic tape conforming to the width, color, and printing requirements specified above, with a minimum thickness of 0.004 inch, and a minimum strength of 1500 psi lengthwise and 1250 psi crosswise. Manufacture tape with integral wires, foil backing, or other means of enabling detection by a metal detector when tape is buried up to 3 feet deep. Encase metallic element of the tape in a protective jacket or provide with other means of corrosion protection.

2.3 DETECTION WIRE FOR NON-METALLIC PIPING

Insulate a single strand, solid copper detection wire with a minimum of 12

AWG.

2.4 BRIDGING MATERIAL

Provide bridging material consisting of clean, poorly graded crushed or uncrushed rock or gravel. Conform to ASTM C33/C33M for coarse aggregate grading between Size No. 3 and Size No. 5 or as otherwise approved or

SECTION 31 00 00 Page 9 Amendment 0005 directed by the Contracting Officer.

2.5 CONTROLLED LOW STRENGTH MATERIAL

Controlled Low Strength Material (CLSM) shall be as defined in ACI 229R And shall consist of lean slurry of Type II Portland cement blended with size number 8 coarse rounded aggregate conforming to the requirements specified in ASTM C33/C33M. Admixtures containing calcium chloride shall not be used. The Contractor may elect to increase the flow-ability by using fly ash as the aggregate filler. CLSM shall have a 28-day compressive strength of 50 to 100 psi when tested in accordance with

ASTM D4832.

PART 3 EXECUTION

3.1 GENERAL EXCAVATION

Perform excavation of every type of material encountered within the limits of the project to the lines, grades, and elevations indicated and as specified. Perform the grading in accordance with the typical sections shown and the tolerances specified in paragraph FINISHING. Transport satisfactory excavated materials and place in fill or embankment within the limits of the work. Excavate unsatisfactory materials encountered within the limits of the work below grade and replace with satisfactory materials as directed. Include such excavated material and the satisfactory material ordered as replacement in excavation. Dispose surplus satisfactory excavated material not required for fill or embankment and unsatifactory excavated material as specified in paragraph

3.13 DISPOSITION OF SURPLUS MATERIAL.in areas approved for surplus material storage or designated waste areas. Dispose unsatisfactory excavated material in designated waste or spoil areas. During construction, perform excavation and fill in a manner and sequence that will provide proper drainage at all times. Excavate material required for fill or embankment in excess of that produced by excavation within the grading limits from the borrow areas indicated or from other approved areas selected by the Contractor as specified.

3.1.1 Ditches, Gutters, and Channel Changes

Finish excavation of ditches, gutters, and channel changes by cutting accurately to the cross sections, grades, and elevations shown on drawings. Do not excavate ditches and gutters below grades shown.

Backfill the excessive open ditch or gutter excavation with satisfactory, thoroughly compacted, material or with suitable stone or cobble to grades shown. Dispose excavated material as shown or as directed, except in no case allow material be deposited a maximum 4 feet from edge of a ditch.

Maintain excavations free from detrimental quantities of leaves, brush, sticks, trash, and other debris until final acceptance of the work.

3.1.2 Drainage Structures

Make excavations to the lines, grades, and elevations shown, or as directed. Provide trenches and foundation pits of sufficient size to permit the placement and removal of forms for the full length and width of structure footings and foundations as shown. Clean rock or other hard foundation material of loose debris and cut to a firm, level, stepped, or serrated surface. Remove loose disintegrated rock and thin strata. Do not disturb the bottom of the excavation when concrete or masonry is to be placed in an excavated area. Do not excavate to the final grade level

SECTION 31 00 00 Page 10 Amendment 0005 until just before the concrete or masonry is to be placed. Where pile foundations are to be used, stop the excavation of each pit at an elevation 1 foot above the base of the footing, as specified, before piles are driven. After the pile driving has been completed, remove loose and displaced material and complete excavation, leaving a smooth, solid, undisturbed surface to receive the concrete or masonry.

3.1.3 Drainage

Provide for the collection and disposal of surface and subsurface water encountered during construction. Completely drain construction site during periods of construction to keep soil materials sufficiently dry.

Construct storm drainage features (ponds/basins) at the earliest stages of site development, and throughout construction grade the construction area to provide positive surface water runoff away from the construction activity and provide temporary ditches, swales, and other drainage features and equipment as required to maintain dry soils. When unsuitable working platforms for equipment operation and unsuitable soil support for subsequent construction features develop, remove unsuitable material and provide new soil material as specified herein. It is the responsibility of the Contractor to assess the soil and ground water conditions presented by the plans and specifications and to employ necessary measures to permit construction to proceed.

3.1.4 Dewatering

Control groundwater flowing toward or into excavations to prevent sloughing of excavation slopes and walls, boils, uplift and heave in the excavation and to eliminate interference with orderly progress of construction. Do not permit French drains, sumps, ditches or trenches 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. Take control measures 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, maintain the water level continuously, at least 2 feet below the working level.

3.1.5 Trench Excavation Requirements

Excavate the trench as recommended by the manufacturer of the pipe to be installed. Slope trench walls below the top of the pipe, or make vertical, and of such width as recommended in the manufacturer's printed installation manual. Provide vertical trench walls where no manufacturer's printed installation manual is available. Shore trench walls more than 5 feet high, cut back to a stable slope, or provide with equivalent means of protection for employees who may be exposed to moving ground or cave in. Shore vertical trench walls more than 5 feet high.

Excavate trench walls which are cut back to at least the angle of repose of the soil. Give special attention to slopes which may be adversely affected by weather or moisture content. Do not exceed the trench width below the pipe top of 24 inches plus pipe outside diameter (O.D.) for pipes of less than 24 inches inside diameter, and do not exceed 36 inches plus pipe outside diameter for sizes larger than 24 inches inside diameter. Where recommended trench widths are exceeded, provide redesign, stronger pipe, or special installation procedures by the Contractor. The Contractor is responsible for the cost of redesign, stronger pipe, or special installation procedures without any additional cost to the Government.

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3.1.5.1 Bottom Preparation

Grade the bottoms of trenches accurately to provide uniform bearing and support for the bottom quadrant of each section of the pipe. Excavate bell holes to the necessary size at each joint or coupling to eliminate point bearing. Remove stones of 2 inch or greater in any dimension, or as recommended by the pipe manufacturer, whichever is smaller, to avoid point bearing.

3.1.5.2 Removal of Unyielding Material

Where unyielding material is encountered in the bottom of the trench, remove such material 3 inch below the required grade and replaced with suitable materials as provided in paragraph BACKFILLING AND COMPACTION.

3.1.5.3 Removal of Unstable Material

Where unstable material is encountered in the bottom of the trench, remove such material to the depth directed and replace it to the proper grade with select granular material as provided in paragraph BACKFILLING AND COMPACTION. When removal of unstable material is required due to the Contractor's fault or neglect in performing the work, the Contractor is responsible for excavating the resulting material and replacing it without additional cost to the Government.

3.1.5.4 Excavation for Appurtenances

Provide excavation for manholes, catch-basins, inlets, or similar structures sufficient to leave at least 12 inches clear between the outer structure surfaces and the face of the excavation or support members.

Specify removal of unstable material. When concrete or masonry is to be placed in an excavated area, take special care not to disturb the bottom of the excavation. Do not excavate to the final grade level until just before the concrete or masonry is to be placed.

3.1.5.5 Jacking, Boring, and Tunneling

Unless otherwise indicated, provide excavation by open cut except that sections of a trench may be jacked, bored, or tunneled if, in the opinion of the Contracting Officer, the pipe, cable, or duct can be safely and properly installed and backfill can be properly compacted in such sections.

3.1.6 Underground Utilities

The Contractor is responsible for movement of construction machinery and equipment over pipes and utilities during construction. Excavation made with power-driven equipment is not permitted within 2 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.

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3.1.7 Structural Excavation

Ensure that subgrades have been inspected and approved by the Contracting Officer prior to concrete placement. Backfill and compact any necessary over excavation and changes in grade to 95 percent of ASTM D1557 maximum density.

3.2 OPENING AND DRAINAGE OF EXCAVATION AND BORROW PITS

Except as otherwise permitted, excavation areas shall be provided with adequate drainage. Transport overburden and other spoil material to designated spoil areas or otherwise dispose of as directed. Ensure that excavation of any area, or dumping of spoil material results in minimum detrimental effects on natural environmental conditions.

3.3 STOCKPILING AREAS

Keep stockpiles in a neat and well drained condition, giving due consideration to drainage at all times. Clear, grub, and seal by rubber-tired equipment, the ground surface at stockpile locations;

separately stockpile excavated satisfactory and unsatisfactory materials.

Protect stockpiles of satisfactory materials from contamination which may destroy the quality and fitness of the stockpiled material. If the Contractor fails to protect the stockpiles, and any material becomes unsatisfactory, remove and replace such material with satisfactory material from approved sources.

3.4 FINAL GRADE OF SURFACES TO SUPPORT CONCRETE

Do not excavate to final grade or perform final compaction and testing, until just before concrete is to be placed.

3.5 GROUND SURFACE PREPARATION

3.5.1 General Requirements

Remove and dispose of unstable unsatisfactory material encountered in surfaces to receive fill or in excavated areas, and replace with granular material segregated and stockpiled during project excavations; paymen thereof will be in accordnce with the applicable Unit Price Bid Item. Any nested intact cobbles/boulders which proturude less than 6 inches above the ground surface following planned excavations shall be left undisturbed, and the initial fill layer shall be 10 inched loose thicknedd with Contracting Officer approval. Plow, step, bench, or break up sloped surfaces steeper than 1 vertical to 4 horizontal so that the fill material will bond with the existing material. When the surface is less than the specified density, break up the ground surface to a minimum depth of 6 inches, pulverize, moisture condition (aerate or moisten as necessary to facilitate compactions), and compact as specified in paragraph BACKFILLING AND COMPACTIONy. When the subgrade is part fill and part excavation or natural ground, scarify the excavated or natural ground portion to a depth of 12 inches and compact it as specified for the adjacent fill.

3.5.2 Frozen Material

Do not place or compact froxen materials, and do not place materialon surfaces that are muddy, frozen, or contain frost. Finish compaction by sheepsfoot rollers, pneumatic-tired rollers, steel-wheeled rollers, or other approved equipment well suited to the soil being compacted. Moisten

SECTION 31 00 00 Page 13 Amendment 0005 material as necessary to plus or minus 2percent of optimum moisture.

3.6 UTILIZATION OF EXCAVATED MATERIALS

Use satisfactory material removed from excavations, insofar as practicable, in the construction of fills, embankments, subgrades, shoulders, bedding (as backfill), and for similar purposes. Dispose of unsatisfactory material and any surplus satisfactory material, in accordance with paragraph "DISPOSITION OF SURPLUS MATERIAL". Do not dispose excavated material to obstruct the flow of any stream, endanger a partly finished structure, impair the efficiency or appearance of any structure, or be detrimental to the completed work in any way.

3.7 BURIED TAPE AND DETECTION WIRE

3.7.1 Buried Warning and Identification Tape

Provide buried utility lines with utility identification tape. Bury tape 12 inches below finished grade; under pavements and slabs, bury tape 6 inches below top of subgrade.

3.7.2 Buried Detection Wire

Bury detection wire directly above non-metallic piping at a distance not to exceed 12 inches above the top of pipe. Extend the wire continuously and unbroken, from manhole to manhole. Terminate the ends of the wire inside the manholes at each end of the pipe, with a minimum of 3 feet of wire, coiled, remaining accessible in each manhole. Furnish insulated wire over it's entire length. Install wires at manholes between the top of the corbel and the frame, and extend up through the chimney seal between the frame and the chimney seal. For force mains, terminate the wire in the valve pit at the pump station end of the pipe.

3.8 BACKFILLING AND COMPACTION

Place backfill adjacent to any and all types of structures, in successive horizontal layers of loose materia not more than 8 inches in depth.

Compact to at least 90 percent laboratory maximum density for cohesive materials or 95 percent laboratory maximum density for cohesionless materials, to prevent wedging action or eccentric loading upon or against the structure. Backfill material must be within the range of -2 to +2 percent of optimum moisture content at the time of compaction.

Prepare ground surface on which backfill is to be placed and provide compaction requirements for backfill materials in conformance with the applicable portions of paragraphs GROUND SURFACE PREPARATION. Finish compaction by sheepsfoot rollers, pneumatic-tired rollers, steel-wheeled rollers, vibratory compactors, or other approved equipment.

3.8.1 Trench Backfill

Backfill trenches to the grade shown. Do not backfill the trench until all specified tests are performed.

3.8.1.1 Replacement of Unyielding Material

Replace unyielding material removed from the bottom of the trench with select granular material or initial backfill material.

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3.8.1.2 Replacement of Unstable Material

For materials that will not dry-back sufficiently, remove from the bottom of the trench or excavation and replace with select granular or bridging material or other approved material placed in layers not exceeding 6 inches loose thickness or as otherwise directed.

3.8.1.3 Bedding and Initial Backfill

Provide bedding of the type and thickness shown in the Contract Drawings or as listed in the Conduit Manufactirer's installation literature if more strigent. Place initial backfill material and compact it with approved tampers to a height of at least one foot above the utility pipe or conduit. Bring up the backfill evenly on both sides of the pipe for the full length of the pipe. Take care to ensure thorough compaction of the fill under the haunches of the pipe. Except as specified otherwise in the individual piping section, provide bedding for buried piping in accordance with AWWA C600, Type 4, except as specified herein. Compact backfill to top of pipe to 95 percent of ASTM D1557 maximum density. Provide plastic piping with bedding to spring line of pipe. Provide materials as follows:

3.8.1.3.1 Class I

Angular, 0.25 to 1.5 inch, graded stone, including a number of fill materials that have regional significance such as coral, slag, cinders, crushed stone, and crushed shells.

3.8.1.3.2 Class II

Coarse sands and gravels with maximum particle size of 1.5 inch, including various graded sands and gravels containing small percentages of fines, generally granular and noncohesive, either wet or dry. Soil Types GW, GP, SW, and SP are included in this class as specified in ASTM D2487.

3.8.1.3.3 Gravel and Crushed Stone

Clean, coarsely graded natural gravel, crushed stone or a combination thereof identified having a classification of GW or GP in accordance with ASTM D2487 for bedding and backfill as indicated. Do not exceed maximum particle size of 3 inches.

3.8.1.4 Final Backfill

Fill the remainder of the trench, except for special materials for pavements, with satisfactory material. Place backfill material and compact in accordance with the requirements of paragraph "BACKFILLING AND COMPACTION" and as follows:

a. Pavement Areas Including Pads: Place backfill consisting of satisfactory and base/subbase materials up to the required elevations as indicated and as specified herein and in applicable specification SECTIONS. Do not permit water flooding or jetting methods of compaction.

b. Turfed or Seeded Areas and Miscellaneous Areas: Deposit backfill in layers of a maximum of 12 inches loose thickness, and compact it to 90 percent maximum density. Do not permit compaction by water flooding or jetting. Apply this requirement to all other areas not specifically designated above.

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3.8.2 Backfill for Appurtenances

After the manhole, catchbasin, inlet, or similar structure has been constructed and the concrete has been allowed to cure for 7 days, place backfill in such a manner that the structure is not be damaged by the shock of falling earth. Deposit the backfill material, compact it as specified for final backfill, and bring up the backfill evenly on all sides of the structure to prevent eccentric loading and excessive stress.

3.9 SPECIAL REQUIREMENTS

Special requirements for both excavation and backfill relating to the specific utilities are as follows:

3.9.1 Gas Distribution

Excavate trenches to a depth that will provide a minimum 18 inches of cover in rock excavation and a minimum 24 inch of cover in other excavation.

3.9.2 Water Lines

Excavate trenches to a depth that provides a minimum cover of 3 feet from the existing ground surface, or from the indicated finished grade, whichever is lower, to the top of the pipe.

3.9.3 Heat Distribution System

Free initial backfill material of stones larger than 1/4 inch in any dimension.

3.9.4 Electrical Distribution System

Provide a minimum cover of 24 inches from the finished grade to direct burial cable and conduit or duct line, unless otherwise indicated.

3.10 SUBGRADE PREPARATION

3.10.1 Construction

Subgrade as used herein refers to the upper 6 inches of earth materials directly below new granular subbase and/or separation layer materials in pavement areas including shoulders. Shape subgrade to line, grade, and cross section, and compact as specified. Remove soft or otherwise unsatisfactory or unstable material and replace with bridging or select granular material or other approved material as directed. After rolling, the surface of the subgrade for pavement areas shall not show deviations greater than 1/2 inch when tested with a 12-foot straightedge applied both parallel and at right angles to the centerline of the area. Do not vary the elevation of the finish subgrade more than 0.05 foot from the established grade and cross section.

3.10.2 Compaction

Finish compaction by pneumatic-tired rollers, tamping-pad or smooth-drum steel-wheeled rollers, vibratory compactors, or other approved equipment.

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3.11 FINISHING

Finish the surface of excavations, embankments, and subgrades to a smooth and compact surface in accordance with the lines, grades, and cross sections or elevations shown. Provide the degree of finish for graded areas within 0.1 foot of the grades and elevations indicated except that the degree of finish for subgrades specified in paragraph SUBGRADE

PREPARATION.

3.11.1 Subgrade

During construction, keep embankments and excavations shaped and drained.

Maintain ditches and drains along subgrade to drain effectively at all times. Do not disturb the finished subgrade by traffic or other operation. Protect and maintain the finished subgrade in a satisfactory condition until subbase, base, surfacing, or pavement is placed. Do not permit the storage or stockpiling of materials on the finished subgrade.

Do not lay subbase, base course, or pavement until the subgrade has been checked and approved, and in no case place subbase, base, surfacing, pavement on a muddy, spongy, or frozen subgrade.

3.11.2 Grading Around Structures

Construct areas within 5 feet outside of each building and structure line true-to-grade, shape to drain, and maintain free of trash and debris until final inspection has been completed and the work has been accepted.

3.12 TESTING

Perform testing by a Corps validated commercial testing laboratory meeting the requirements of SECTION 01 45 00 QUALITY CONTROL and approved by the Contracting Officer.

a. Determine field in-place density in accordance withthe sand cone method ASTM D1556/D1556M , except the nuclear gauge method ASTM D6938 may be used, as further qualified hereinafter, to determine in-place density of materials verified to be free of mica or other material known to give inconsistent nuclear gauge readings. When nuclear gauge testing per ASTM D6938 is used, check the calibration curves as described in ASTM D6938 , and using ASTM D2937 for fine-grained soils and ASTM D1556/D1556M for granular soils when performing any necessary test site calibration as described in Annex 2 paragraph A2.1.6. Check the calibration of the density gauge prior to the first use of each different type of material encountered and at intervals as directed by the Contracting Officer. Both ASTM D1556/D1556M and ASTM D6938 result in a wet unit weight of soil and when using either of these methods, use only method ASTM D2216 to determine the moisture content for calculating in-place dry density of the soil. For a rough estimate of in-place density to control field activities only, the Contractor may perform moisture content testing by method ASTM D4643 or ASTM D4959 in conjunction with density testing by method ASTM D6938 .

Density results determined by sand cone method ASTM D1556/D1556M shall govern, and shall be used at the frequency specified below to adjust the results determined for similar materials by nuclear gauge method ASTM D6938. If differing results are consistently determined, use of the nuclear gauge shall be discontinued and only sand cone method ASTM D1556/D1556M shall be used. When test results indicate, as determined by the Contracting Officer, that compaction is not as specified, remove the material, replace and recompact to meet

SECTION 31 00 00 Page 17 Amendment 0005 specification requirements. Perform tests on recompacted areas to determine conformance with specification requirements. For all tests required by these specifications, appoint a registered professional civil engineer to certify inspections and test results. These certifications shall state that the tests and observations were performed by or under the direct supervision of the engineer and that the results are representative of the materials or conditions being certified by the tests. The following number of tests, if performed at the appropriate time, will be the minimum acceptable for each type operation.

3.12.1 Fill and Backfill Material Gradation

One test per 500 cubic yards stockpiled or in-place source material.

Determine gradation of fill and backfill material in accordance with

ASTM C136/C136M.

3.12.2 In-Place Densities

a. One test per 5000 square feet, or fraction thereof, of each lift of fill or backfill areas compacted by other than hand-operated machines.

b. One test per 1000 square feet, or fraction thereof, of each lift of fill or backfill areas compacted by hand-operated machines.

3.12.3 Check Tests on In-Place Densities

If nuclear gauge method ASTM D6938 is used, check in-place densities by the sand cone method ASTM D1556/D1556M at a minimum frequency of one sand cone test per lift for every ten or fraction thereof tests by the nuclear gauge method. Use these sand cone "check test" results to calibrate (adjust) the nuclear gauge results for representative materials as described in paragraph "TESTING" above.

3.12.4 Moisture Contents

In the stockpile, excavation, or borrow areas, perform a minimum of two tests per day per type of material or source of material being placed during stable weather conditions. During unstable weather, perform tests as dictated by local conditions and approved by the Contracting Officer.

3.12.5 Optimum Moisture and Laboratory Maximum Density

Perform tests for each type material or source of material to determine the optimum moisture and laboratory maximum density values. One representative test per 500 cubic yards of fill and backfill, or when any change in material occurs which may affect the optimum moisture content or laboratory maximum density.

3.12.6 Tolerance Tests for Subgrades

Perform continuous checks on the degree of finish specified in paragraph SUBGRADE PREPARATION during construction of the subgrades.

3.12.7 Controlled Strength Material

Two set of samples shall be collected for testing for backfilling of the 2-24" steel force mains for each 20 cubic yards placed or for each placement shift whichever produces the greatest number of tests. One set

SECTION 31 00 00 Page 18 Amendment 0005 of samples shall be taken at the beginning of placement and the other set near the end of placement. The Contractor shall perform unconfined compressive strength tests in accordance with ASTM D4832 at 7, 14 and 28-day aged samples and another set of hydraulic conductivity test in accordance with ASTM D5084 at 7, 14 and 28-day.

3.13 DISPOSITION OF SURPLUS MATERIAL

Surplus material or other soil material not required or suitable for filling or backfilling, and brush, refuse, stumps, roots, and timber shall be removed from Government property and properly disposed of in accordance with all applicable laws and regulations.

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1.6 SUBMITTALS

3.8.1.4 Final Backfill

3.8.2 Backfill for Appurtenances

3.13 DISPOSITION OF SURPLUS MATERIAL