Technical Exhibit V-Div 31 EARTHWORK 23 May 2023.pdf

POM Job Order Contracting (SATOC) 2503

SECTION TABLE OF CONTENTS

DIVISION 31 - EARTHWORK

SECTION 31 00 00

EARTHWORK

08/ 08, CHG 2: 02/ 21

PART 1 GENERAL

1.1 REFERENCES

1.2 1.2 STATE SPECIFICATIONS

1.3 DEFINITIONS

1.3.1 Satisfactory Materials

1.3.2 Unsatisfactory Materials

1.3.3 Cohesionless and Cohesive Materials

1.3.4 Degree of Compaction

1.3.5 Hard/Unyielding Materials

1.3.6 Rock

1.3.7 Unstable Material

1.3.8 Select Granular Material

1.3.8.1 General Requirements

1.3.9 Initial Backfill Material

1.4 INSTALLATION-SPECIFIC DATA

1.4.1 Classification of Excavation

1.4.2 Blasting

1.5 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 CAPILLARY WATER BARRIER

2.6 PIPE CASING

2.6.1 Casing Pipe

2.6.2 Wood Supports

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

SECTION 31 00 00 Page 1

3.1.6 Underground Utilities

3.1.7 Structural Excavation

3.2 SHORING

3.2.1 General Requirements

3.2.2 Geotechnical Engineer

3.3 STOCKPILE MANAGEMENT

3.4 FINAL GRADE OF SURFACES TO SUPPORT CONCRETE

3.5 GROUND SURFACE PREPARATION

3.5.1 General Requirements

3.5.2 Mitigation of Unstable Materials

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 FILLING, 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

3.8.1.4 Final Backfill

3.8.1.4.1 Buildings and Pavements/Pads including Walkways

3.8.1.4.2 Turfed or Seeded Areas and Miscellaneous Areas

3.8.2 Backfill for Appurtenances

3.9 SPECIAL REQUIREMENTS

3.9.1 Gas Distribution

3.9.2 Water Lines

3.9.3 Electrical Distribution System

3.9.4 Pipeline Casing

3.9.4.1 Bore Holes

3.9.4.2 Cleaning

3.9.4.3 End Seals

3.10 EMBANKMENTS

3.10.1 Earth Embankments

3.11 SUBGRADE PREPARATION

3.11.1 Construction

3.11.2 Compaction

3.12 SHOULDER CONSTRUCTION

3.13 FINISHING

3.13.1 Subgrade and Embankments

3.13.2 Capillary Water Barrier

3.13.3 Grading Around Structures

3.14 TESTING

3.14.1 Fill and Backfill Material Gradation

3.14.2 In-Place Densities

3.14.3 Check Tests on In-Place Densities

3.14.4 Moisture Contents

3.14.5 Optimum Moisture and Laboratory Maximum Density

3.14.6 Tolerance Tests for Subgrades

3.14.7 Displacement of Sewers

3.15 DISPOSITION OF SURPLUS MATERIAL

-- End of Section Table of Contents --

SECTION 31 00 00 Page 2

SECTION 31 00 00

EARTHWORK

08/ 08, CHG 2: 02/ 21

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 within the text by the basic designation only.

AMERICAN CONCRETE INSTITUTE (ACI)

ACI 229R-13 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 (2020; Errata 1 2021) 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 C33/C33M (2018) Standard Specification for Concrete Aggregates

ASTM C136/C136M (2019) Standard Test Method for Sieve Analysis of Fine and Coarse 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

SECTION 31 00 00 Page 3

Laboratory Compaction Characteristics of Soil Using Modified Effort (56,000 ft-lbf/ft3) (2700 kN-m/m3)

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

ASTM D2487 (2017; E 2020) 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 D4718/D4718M (2015) Standard Practice for Correction of Unit Weight and Water Content for Soils Containing Oversize Particles

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

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

STATE OF CALIFORNIA DEPARTMENT OF TRANSPORTATION (Caltrans)

Section 26 (2022) Section 26 Aggregate Bases

U.S. ARMY CORPS OF ENGINEERS (USACE)

EM 385-1-1 (2014) Safety -- 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 (2007, Fourth Edition, Update IV-A and IV-B) Test Methods for Evaluating Solid Waste: Physical/Chemical Methods

1.2 1.2 STATE SPECIFICATIONS

STATE OF CALIFORNIA DEPARTMENT OF TRANSPORTATION (Caltrans), STANDARD SPECIFICATIONS, latest edition (including all subsequent supplements and updates), are referred to herein as State Specifications. Paragraphs

SECTION 31 00 00 Page 4 pertaining to measurement and payment in the State Specifications do not apply. References to State or Engineer are understood to be the Contracting Officer. The State Specifications to the extent referenced hereinafter form a part of this specification for material acceptance only, and all other aspects of construction including but not limited to testing, placement, compaction and field quality control, are required as specified herein.

1.3 DEFINITIONS

1.3.1 Satisfactory Materials

Satisfactory materials for fill and backfill comprise any materials classified by ASTM D2487 as GW, GP, GM, GP-GM, GC, SW, SP, SM, SC, SP-SM, SP-SC, CL, ML, or any combination thereof and having a maximum particle size of 3 inches in any dimension. Satisfactory materials encountered at the base of planned excavations include the above, plus MH and CH materials only if in a stable condition.

1.3.2 Unsatisfactory Materials

Materials which do not comply with the requirements for satisfactory materials including but not limited to those classified as OL, OH, and PT, 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.

1.3.3 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.

1.3.4 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 ASTM D1557 Method C and corrected with ASTM D4718/D4718M . .

1.3.5 Hard/Unyielding Materials

Hard/Unyielding materials comprise weathered rock, dense consolidated deposits, or conglomerate materials which are not included in the definition of "rock" with stones greater than 3 inch in any dimension or as defined by the pipe manufacturer, whichever is smaller. These materials usually require the use of heavy excavation equipment, ripper teeth, or jack hammers for removal.

SECTION 31 00 00 Page 5

1.3.6 Rock

Solid homogeneous interlocking crystalline material with firmly cemented, laminated, or foliated masses or conglomerate deposits, neither of which can be removed without 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.

1.3.7 Unstable Material

Unstable materials are those soil materials that rut and shove under the weight of construction equipment or during proof rolling operations, and that are unable to support the required new construction. Unstable materials generally have water contents of 5 percent or more above optimum, but this percentage can be lower if equipment is excessively heavy or used inappropriately.

1.3.8 Select Granular Material

1.3.8.1 General Requirements

Select granular material excludes recycled concrete and asphalt materials and consists of soil materials classified as GW, GP, GC, SW, SC, SP, or any combination thereof by ASTM D2487 and as further defined herein. The liquid limit of such material must not exceed 30 percent and the plasticity index must not be greater than 10 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 30 percent by weight may be finer than No. 200 sieve when tested in accordance with ASTM D1140.

1.3.9 Initial Backfill Material

Initial backfill and bedding material, unless otherwise indicated on the drawings, consists of select granular material or equivalent material as specified by the conduit or coating manufacture for the specific conduit type, coating type, trench configuration, and surface loading condition.

Where the pipe-conduit is coated or wrapped for corrosion protection, the initial backfill material consists of sand meeting ASTM C33/C33M Concrete Fine Aggregate unless other material is specified by the manufacturer.

The Contractor, at their responsibility and expense and with Contracting Officer and pipe manufacturer approvals, may elect instead to use excavatable Controlled Low-Strength Materials (CLSM) for bedding and initial backfill. CLSM shall be as described in ACI 229R-13 and produced with aggregates having a maximum size of 1/4-inch and having a 28-day compressive strength between 50 psi and 100 psi.

1.4 INSTALLATION-SPECIFIC DATA

At Ord Military Community (OMC) formerly known as Fort Ord, native soils generally consist of very fine wind-blown dune sand with silt, which are typically loose in the upper few feet. Over-excavate existing soils in undeveloped i.e. 'virgin' areas and replace in controlled lifts prior to constructing new foundations, pavements and slabs or pads. Over-excavate to the deeper of 36 inches below existing grade or 18 inches below footing, slab, or pavement base course. Provide a minimum 6-inch layer of aggregate base course on the prepared subgrade/fill, to form a dense and stable surface for foundation, slab-on-grade, and equipment pad concrete.

SECTION 31 00 00 Page 6

Provide at least 24 inches of cover over top of perimeter footings where backfill will not be covered by pavement. ved backfill. Compact all fill and backfill materials to at least 95 percent of laboratory maximum. The Contractor is cautioned that native soils at OMC can be difficult to compact with vibratory smooth steel-wheel rollers that are commonly used by industry for granular materials. USACE Sacramento historic geotechnical reports recommended several coverages by a heavy crawler-type tractor followed by large pneumatic-tired rollers. Jack-and-bore methods for utility installation are prohibited at OMC.

At Presidio Monterey (POM, provide waterproofing treatment and sub-drains against the exterior of perimeter foundation walls. Subdrains consist of minimum 4-inch slotted pipe surrounded by a minimum 12x24 inch gravel blanket enveloped by non-woven geotextile fabric with AOS of 70-100. Place the pipe 4 inches above the gravel bottom and use a solid discharge pipe to connect it to a nearby storm drain structure, or run the discharge pipe to a paved or gravel-protected free exit as approved by the Contracting Officer.

Native soils at Presidio Monterey (POM) are generally found to be moderately corrosive at or above field moisture content. Provide cathodic protection or other approved method to protect metal utilities in accordance with applicable provisions of UFC 3-570-02A and UFC 3-570-06.

Subsurface soil data from historic explorations, when available from the Installation and/or USACE Sacramento, are included with the contract documents. These data represent the best subsurface information available; however, variations may exist in the subsurface between boring locations.

1.4.1 Classification of Excavation

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

1.4.2 Blasting

Blasting will not be permitted.

1.5 SUBMITTALS

Government approval is required for submittals with a "G" classification.

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

SD-03 Product Data

Utilization of Excavated Materials; G Shoulder Construction

SD-06 Test Reports

Testing

Borrow Site Testing

SD-07 Certificates

Testing

SECTION 31 00 00 Page 7

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. Provide backfill containing a maximum concentration of tested constituents as allowed by CalEPA and 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.

2.2 BURIED WARNING AND IDENTIFICATION TAPE

Provide 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

SECTION 31 00 00 Page 8 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

Bridging material is satisfactory for the stabilization of local, surficial, unstable areas in non-building areas only. Bridging material for unstable material remediation consists of crushed stone or crushed gravel size number 4 or 56 conforming to ASTM C33/C33M. At Contractor sole responsibility and if approved by the Contracting Officer, State Specification Section 26 Aggregate Base or UFGS SECTION 32 11 23 ABC may be used for bridging if conditions dictate.

2.5 CAPILLARY WATER BARRIER

Provide capillary water barrier of clean, poorly graded crushed rock, crushed gravel, or uncrushed gravel placed beneath a building slab with or without a vapor barrier to cut off the capillary flow of pore water to the area immediately below. Conform to ASTM C33/C33M coarse aggregate Size 57, 67, or 77. State Specification Section 26 Class 2 Aggregate Base or UFGS SECTION 32 11 23 ABC may be substituted in areas with relatively dry soils and deep groundwater, subject to Contracting Officer approval.

2.6 PIPE CASING

2.6.1 Casing Pipe

ASTM A139/A139M , Grade B, or ASTM A252, Grade 2, smooth wall pipe. Match casing size to the outside diameter and wall thickness as indicated on Drawing Sheet. Protective coating is not required on casing pipe.

2.6.2 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. Secure wood supports to carrier pipe with stainless steel or zinc-coated steel bands.

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 and in accordance with with the requirements of the Corps of Engineers publication EM 385-1-1 Safety and Health Requirements Manual.

Include indicated over-excavation and replacement in building and pavement areas. Perform the grading in accordance with the typical sections shown and the tolerances specified in paragraph FINISHING. Nandle excavated materials in accordance with applicable requirements in paragraph STOCKPILE MANAGEMENT, paragraph UTILIZATION OF EXCAVATED MATERIALS, and

SECTION 31 00 00 Page 9 paragraph DISPOSITION OF SURPLUS MATERIAL.

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 Drawing.

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. 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 until just before the concrete or masonry is to be placed.

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/or 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. Operate dewatering system continuously until construction work below existing water levels is complete. Submit performance records weekly.

SECTION 31 00 00 Page 10

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, 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, as determined by the Contractor’s Safety Engineer or other competent person; refer to USACE publication EM 385-1-1 . 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.

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 3 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 overdepth is not indicated and unyielding material is encountered in the bottom of the trench, remove such material 4 inches below the required grade and replace with suitable materials as provided in paragraph

FILLING, 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 FILLING, 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 of sufficient size to permit the placement and removal of forms for the full length and width of structure footings and foundations as shown. 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.

SECTION 31 00 00 Page 11

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, or as otherwise required by the utility company/owner, of known 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.

3.1.7 Structural Excavation

The Contractor's Geotechnical Engineer and the Contractor's Quality Control or technical representative shall physically enter and probe excavated surfaces in the presence of the Contracting Officer to check for loose or soft-unstable areas and to verify proper subgrade bearing.

3.2 SHORING

3.2.1 General Requirements

Where project conditions and Contractor methods dictate the need for shoring, submit a Shoring and Sheeting plan for approval 15 days prior to starting work. Submit drawings and calculations, certified by a registered professional engineer, describing the methods for shoring and sheeting of excavations. Finish shoring, including sheet piling, and install as necessary to protect workmen, banks, adjacent paving, structures, and utilities. Remove shoring, bracing, and sheeting as excavations are backfilled, in a manner to prevent caving.

3.2.2 Geotechnical Engineer

Hire a licensed Professional Engineer specializing in Geotechnical Engineering and having a minimum of 3 years of experience working with subsurface conditions representative of those existing in the project vicinity. The Geotechnical Engineer is responsible for performing pre-construction and periodic site visits throughout construction to assess site conditions. The Geotechnical Engineer is responsible for updating any necessary excavation, sheeting and dewatering plans as construction progresses to reflect changing conditions and submit an updated plan if necessary. The Contractor is responsible for arranging any requested or necessary meetings with the Contracting Officer and Geotechnical Engineer at any time throughout the contract duration.

3.3 STOCKPILE MANAGEMENT

Place and grade stockpiles of satisfactory, unsatisfactory, and wasted

SECTION 31 00 00 Page 12 materials as specified. 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 compliance testing until just before concrete is to be placed. Protect all surfaces from erosion or degradation resulting from ponding or water flow. Provide a 6-inch layer of aggregate base course compacted to at least 95 percent of laboratory maximum dry density beneath foundations, slabs, equipment pads, and sidewalks.

3.5 GROUND SURFACE PREPARATION

3.5.1 General Requirements

Remove and replace unsatisfactory material with satisfactory materials, as directed by the Contracting Officer, in surfaces to receive fill or in excavated areas. Scarify the surface to a depth of 6 inches before the fill is started. 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 subgrades are less than the specified density, break up the ground surface to a minimum depth of 6 inches, pulverizing, moisture conditioning, and compacting to the specified density in accordance with paragraph FILLING, BACKFILLING, AND COMPACTION. 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.Remove unsatisfactory and unstable material in surfaces to receive fill or other new construction, and replace with specified materials. Do not place material on surfaces that are muddy, frozen, or contain frost. Scarify the surface to a depth of 4 inches prior to placing fill. Step or bench sloped surfaces steeper than 1 vertical to 4 horizontal prior to scarifying. Place 4 inches of loose fill and blend with scarified material. When subgrade is part fill and part excavation or natural ground, scarify to a depth of 8 inches.

Moisture-condition and compact the scarified/blended/fill materials as specified in paragraph FILLING, BACKFILLING AND COMPACTION. Continue with compaction until the specified degree of compaction is achieved.

3.5.2 Mitigation of Unstable Materials

Initial mitigation consists of over-excavation, drying-back, replacement and compaction. When a workable material surface to support overlying new construction cannot be achieved thereby, mitigate as approved or directed by replacing with granular materials, by use of bridging materials, by use of geogrids and/or geotextiles, or by lime or cement modification. When mitigation of unstable material is required due to the Contractor's fault or neglect in performing the work, the Contractor is responsible for performing all necessary mitigation measures without additional cost to the Government.

SECTION 31 00 00 Page 13

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 surplus satisfactory excavated material not required for fill and unsatisfactory excavated material as specified in paragraph DISPOSITION OF SURPLUS MATERIAL. Stockpile and use coarse rock from excavations for constructing erosion-protection features as applicable. Do not dispose excavated material in areas that can 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 its 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 FILLING, BACKFILLING, AND COMPACTION

Prepare ground surface on which fill and backfill is to be placed and provide compaction requirements for fill and backfill materials in conformance with the applicable portions of paragraph GROUND SURFACE PREPARATION. Place satisfactory fill or backfill materials below buildings or adjacent to any and all types of structures in such manner as to prevent wedging action or eccentric loading upon or against the structure. Moisture-condition and place all fill materials in maximum 8-inch loose or 6-inch compacted thickness lifts when using self-propelled machinery, and in maximum 4-inch compacted thickness lifts when using hand-operated machines. Compact to at least 90 percent or 95 percent laboratory maximum dry density for cohesive or cohesionless materials, respectively. Finish compaction by sheepsfoot rollers, pneumatic-tired rollers, tamping-pad or smooth-drum steel-wheeled rollers, vibratory plate compactors, or other approved equipment well-suited to the conditions and materials being compacted.

3.8.1 Trench Backfill

Backfill trenches to the grade shown. Backfill the trench to 2 feet above the top of pipe prior to performing the required pressure tests. Leave the joints and couplings uncovered during the pressure tests. Do not backfill the trench until all specified tests are performed.

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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.

3.8.1.2 Replacement of Unstable Material

Replace unstable material removed from the bottom of the trench or excavation with select granular material placed in layers not exceeding 6 inches loose thickness. Compact as specified for Capillary Water Barrier material or as otherwise directed.

3.8.1.3 Bedding and Initial Backfill

Provide bedding of the type and thickness shown in Contract Drawings or as specified herein or as listed in the Conduit Manufacturer's installation literature if more stringent. Place bedding and 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 at least 90 percent of maximum dry density.

3.8.1.4 Final Backfill

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

3.8.1.4.1 Buildings and Pavements/Pads including Walkways

Place backfill up to the required elevation as specified and/or as indicated. Do not permit water flooding or jetting methods of compaction.

3.8.1.4.2 Turfed or Seeded Areas and Miscellaneous Areas

Deposit backfill in layers of a maximum of 12 inches loose thickness, and compact it to 85 percent maximum density for cohesive soils and 90 percent maximum density for cohesionless soils. Do not permit compaction by water flooding or jetting. Apply this requirement to all other areas not specifically designated above.

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:

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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. For fire protection yard mains or piping, an additional 12 inch of cover is required, or deeper when indicated or specified elsewhere.

3.9.3 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.

3.9.4 Pipeline Casing

Provide new smooth wall steel pipeline casing under by the boring and jacking method of installation. Provide each new pipeline casing, where indicated and to the lengths and dimensions shown, complete and suitable for use with the new piped utility as indicated. As necessary, install pipeline casing by dry boring and jacking method as follows:

3.9.4.1 Bore Holes

Mechanically bore holes and case through the soil with a cutting head on a continuous auger mounted inside the casing pipe. Weld lengths of pipe together in accordance with AWS D1.1/D1.1M . Do not use water or other fluids in connection with the boring operation.

3.9.4.2 Cleaning

Clean inside of the pipeline casing of dirt, weld splatters, and other foreign matter which would interfere with insertion of the piped utilities by attaching a pipe cleaning plug to the boring rig and passing it through the pipe.

3.9.4.3 End Seals

After installation of piped utilities in pipeline casing, provide watertight end seals at each end of pipeline casing between pipeline casing and piping utilities. Provide watertight end seals as indicated.

3.10 EMBANKMENTS

3.10.1 Earth Embankments

Construct earth embankments from satisfactory materials free of organic or frozen material and rocks with any dimension greater than 3 inches. Place the material in successive horizontal layers of loose material not more than 8 inches in depth. Spread each layer uniformly on a soil surface that has been moistened or aerated as necessary, and scarified or otherwise broken up so that the fill will bond with the surface on which it is placed. After spreading, plow, disk, or otherwise break up each

SECTION 31 00 00 Page 16 layer; moisten or aerate as necessary; thoroughly mix; and compact to at least 90 percent laboratory maximum density for cohesive materials or 95 percent laboratory maximum density for cohesionless materials. Backfill and fill material must be to a moisture content that will readily facilitate obtaining the specified compaction.

Compaction requirements for the upper portion of earth embankments forming subgrade for pavements are identical with those requirements specified in paragraph SUBGRADE PREPARATION. Finish compaction by sheepsfoot rollers, pneumatic-tired rollers, steel-wheeled rollers, vibratory compactors, or other approved equipment.

3.11 SUBGRADE PREPARATION

3.11.1 Construction

Subgrade as used herein refers to the upper 12 inches of earth materials directly below footings and directly below granular base/subbase materials in building pad and pavement areas including shoulders. Shape subgrade to line, grade, and cross section, and compact as specified. Include plowing, disking, and any moistening or aerating required to obtain specified compaction for this operation. Remove soft or otherwise unsatisfactory material and replace with satisfactory excavated material or other approved material as directed. Excavate rock encountered in the cut section to a depth of 6 inches below finished grade for the subgrade.

Bring up low areas resulting from removal of unsatisfactory material or excavation of rock to required grade with satisfactory materials, and shape the entire subgrade to line, grade, and cross section and compact as specified. After rolling, do not show deviations for the surface of the subgrade for pavements 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.

3.11.2 Compaction

Finish compaction by sheepsfoot rollers, pneumatic-tired rollers, tamping-pad or smooth-drum steel-wheeled rollers, vibratory compactors, or other approved equipment well-suited to the conditions and material being compacted. Compact the subgrade to at least 90 percent or 95 percent laboratory maximum dry density for cohesive or cohesionless materials, respectively.

3.12 SHOULDER CONSTRUCTION

Construct shoulders of satisfactory material or as otherwise shown or specified.. Submit advanced notice on shoulder construction for rigid pavements. Construct shoulders immediately after adjacent paving is complete. In the case of rigid pavements, do not construct shoulders until permission of the Contracting Officer has been obtained. Place, moisture-condition, and compact materials as specified in paragraph FILLING, BACKFILLING AND COMPACTION. Finish shoulder construction in proper sequence in such a manner that adjacent ditches will be drained effectively and that no damage of any kind is done to the adjacent completed pavement. Align the completed shoulders true to grade and shaped to drain in conformity with the cross section shown.

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3.13 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 for subgrades specified in paragraph SUBGRADE PREPARATION. Finish gutters and ditches in a manner that will result in effective drainage. Finish the surface of areas to be turfed to a smoothness suitable for the application of turfing materials. Repair graded, topsoiled, or backfilled areas prior to acceptance of the work, and re-established grades to the required elevations and slopes.

3.13.1 Subgrade and Embankments

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 ballast, subbase, base, or pavement is placed. Do not permit the storage or stockpiling of materials on the finished subgrade.

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

3.13.2 Capillary Water Barrier

Place a capillary water barrier under concrete floor and area-way slabs grade directly on the subgrade and compact with a minimum of two passes of a hand-operated plate-type vibratory compactor. Substitute aggregate base compacted to 95 percent of laboratory maximum density where indicated or otherwise specfied.

3.13.3 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.

3.14 TESTING

Perform testing by a Corps validated commercial or Contractor established testing laboratory meeting the requirements of SECTION 01 45 00 (or similar number) entitled "QUALITY CONTROL" and approved by the Contracting Officer. Determine field in-place density in accordance with the 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

SECTION 31 00 00 Page 18 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 always 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, discontinue use of the nuclear gauge and use only the sand cone method ASTM D1556/D1556M . When test results indicate, as determined by the Contracting Officer, that compaction is not as specified, remove the material, replace and recompact to meet 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. Provide certifications stating 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.

3.14.1 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 and ASTM D1140.

3.14.2 In-Place Densities

a. One test per 2,000 square feet, or fraction thereof, of each lift of fill or backfill areas compacted by other than hand-operated machines.

b. One test per 1,000 square feet, or fraction thereof, of each lift of fill or backfill areas compacted by hand-operated machines.

3.14.3 Check Tests on In-Place Densities

When 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 six 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.

3.14.4 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.

3.14.5 Optimum Moisture and Laboratory Maximum Density

Perform tests for each type material or source of material including borrow 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.

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3.14.6 Tolerance Tests for Subgrades

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

3.14.7 Displacement of Sewers

After other required tests have been performed and the trench backfill compacted to at least 2 feet above the top of the pipe, inspect the pipe to determine whether significant displacement has occurred. Conduct this inspection in the presence of the Contracting Officer. Inspect pipe sizes larger than 36 inches, while inspecting smaller diameter pipe by shining a light or laser between manholes or manhole locations, or by the use of television cameras passed through the pipe. If, in the judgment of the Contracting Officer, the interior of the pipe shows poor alignment or any other defects that would cause improper functioning of the system, replace or repair the defects as directed at no additional cost to the Government.

3.15 DISPOSITION OF SURPLUS MATERIAL

Remove surplus material and excavated unsatisfactory material not required or suitable for…