Attach 1.Spec 9.31 23 00.09R0007.pdf

Solicitation No. FA5270-09-R-0007

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SECTION 31 23 00

EXCAVATION AND FILL

PART 1 – GENERAL

1.1 REFERENCES:

The publications listed below form a part of this specification to the extent referenced. The publications are referred to in the text by the basic designation only. The most current editions shall be used.

AMERICAN SOCIETY FOR TESTING AND MATERIALS (ASTM):

ASTM D2487 (2006) Classification of Soils for Engineering Purposes (unified Soil Classification System)

JAPANESE INDUSTRIAL STANDARDS (JIS):

JIS A 1210 (1999) Method of Test for Moisture-Density

Relations of Soils Using Rammer

JIS A 1214-95 (1995) Method of Test for Density of Soil by the Sand Replacement Method

JIS 5005 (1993) Crushed Stone and Manufactured Sand for Concrete

1.2 DEFINITIONS

In addition to definitions specified in Section 02221 "Earthwork for Structures”, comply with the following:

a. Backfill: Material used in refilling trench or other excavation.

b. Compaction: The process of mechanical stabilizing a material by increasing its density at a controlled moisture condition. “Degree of Compaction” is expressed as a percentage of the maximum density obtained by the test procedure described in JIS A 210.

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

d. Refill: Material placed in excavation to correct over cut in depth.

e. Unstable Material: Material in trench bottom, which lacks firmness, to maintain alignment and prevent joints from concrete footings cracks or other appurtenance structure during backfilling. This may be material otherwise identified as satisfactory which has been disturbed or saturated.

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1.3 SUBMITTALS :

Submit the following in accordance with Section 01 11 00, "General Requirements". See AF Form

66 on submittal schedule.

a. Statements:

1. Dewatering Plan: Describe methods for removing collected water from open trenches and diverting surface water or piped flow away from work area.

2. Welder’s Certifications: Submit prior to on site welding.

1.4 DELIVERIES, STORAGE, AND HANDLING

Deliver and store materials in a manner to prevent contamination, segregation, and other damage.

1.5 PROTECTION

a. Utilities: Movement of construction machinery and equipment over pipes and utilities during construction shall be at the Contractor's risk. Excavation made with power-driven equipment is not permitted within two feet of known Government-owned utility or subsurface construction. Report damage to utility lines or subsurface construction immediately to the Contracting Officer Revised.

b. Dewatering Plan: Base on site surface and subsurface conditions, available soil and hydrological data.

PART 2 - PRODUCTS

2.1 SOIL MATERIALS

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

a. Backfill: Bring trenches to grade indicated on the drawing using material excavated on the site of this project. This material will be considered unclassified and no testing other than for compaction will be required before use of backfill.

c. Special Backfill for Structures and Pavements: Section 31 00 00; “Earthwork for Structures.”

c. Sand: Clean, coarse-grained sand classified as SW or SP by ASTM D2487 for bedding.

d. Gravel: Clean, coarsely graded crushed stone having a classification of GW or GP in accordance with ASTM D2487 for backfill. Maximum particle size shall not exceed 1-1/2 inches.

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e. Topsoil material: Salvaged topsoil from stockpile. Furnish additional topsoil from approved sources off the site if stockpiled material is insufficient to complete work indicated. Comply with Section 32 92 23, “Sodding” if additional topsoil is required.

f. Borrow: Provide material for pipe bedding consisting of SW, SP, SM or SC as classified in accordance with ASTM D2487.

g. Pipe Bedding: Provide material for pipe bedding consisting of sand as classified in accordance with ASTM D 2487.

PART 3 - EXECUTION

3.1 PROTECTION

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

b. Water Removal: Remove water by pumping or other methods to prevent the softening of surfaces exposed by excavation, prevent hydrostatic uplift, and provide a stable trench condition for installation of the utility. Use screens and gravel packs or other filtering systems on the dewatering devices to prevent the removal of fines from the soil.

c. Structures and Surfaces: Protect newly backfilled areas and adjacent structures, slopes, or grades from traffic, erosion settlement, or any other damage. Repair and reestablish damaged or eroded grades and slopes and restore surface construction prior to acceptance.

d. Operation and Performance: Operate the dewatering system until construction work below existing water levels is complete. Measure and record the performance of the dewatering system. After placement of the conduit and the initial backfill, the water level may be allowed to rise but at no tome allow it to rise higher than one foot pump and system available for immediate use.

3.2 SURFACE PREPARATION

a. Stockpiling Topsoil: Strip suitable soil from the site where excavation is indicated and stockpile separately from other excavated material. Material unsuitable for use as topsoil shall be stockpiled and use for backfilling. Locate topsoil so that the material can be used readily protect topsoil and keep in segregated piles until needed.

b. Cutting Pavement: Saw cut with net, parallel, straight lines one foot wider than trench width on each side of trenches and one foot beyond each edge pits.

3.3 GENERAL EXCAVATION AND TRENCHING

Keep excavations free from water while construction is in progress. Notify the Contracting Officer Representative immediately in writing if it becomes necessary to remove rock or hard, unstable, or otherwise unsatisfactory material to a depth greater than indicated. Make trench sides as nearly vertical as practicable except where sloping of sides is allowed. Sides of trenches shall not

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be sloped from the bottom of the trench up to the elevation of the top of the grade. Excavate ledge rock, boulders, and other unyielding material to an over depth at least 6 inches below the bottom of the conduit unless otherwise indicated. Blasting will not be permitted. Use bedding material placed in 6-inch-maximum layers to refill over depths to the proper grade. Trench dimensions shall be indicated.

3.4 BEDDING

Bedding of materials and depths as specified concrete decorative wall footing. Place bedding in 6-inch maximum loose lifts. Provide uniform and continuous support for each section of structure except at bell holes or depressions necessary for making proper joints.

3.6 BACKFILLING

Construct backfill in two operations (initial and final) specified in this section. Ensure that initially placed material is tamped firmly under pipe haunches. Ensure that no damage is done to the concrete footing. Place the remainder of the backfill (final backfill) in 9-inch maximum loose lifts unless otherwise specified. Compact each loose lift as specified in the paragraph entitled "General Compaction" before placing the next lift. Do not backfill where the material in the trench is muddy, except as authorized. Where settlements greater than the tolerance allowed herein for grading occur in trenches due to improper compaction, excavate to the depth necessary to rectify the problem, then backfill and compact the excavation as specified herein and restore the surface to the required elevation.

3.7 COMPACTION

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

a. Compaction of Material in Over Excavations: In rock, compact to 95 percent of JIS A

1210 maximum density. In soft, weak, or wet soils, tamp refill material to consolidate to density of adjacent material in trench wall. In stable soils, compact to 90 percent of JIS A 1210 maximum density.

b. Compaction of Backfill: Compact initial backfill material surrounding cables, conduits, or ducts, to 90 percent of JIS A 1210 maximum density except where bedding and backfill are the same material. Where bedding and backfill are the same material, compact initial backfill to the density of the bedding. Under areas to be sodded, compact succeeding layers of final backfill to 85 percent of JIS A 1210 maximum density.

d. ConcreteFoundations and Other Appurtenances: Provide at least 12-inch clear from outer surfaces to the embankment. Remove unstable soil that is not capable of supporting the structure to an over depth of one foot and refill with sand or gravel to the proper elevation.

Refill over depths with concrete to the required grade.

3.8 FINISH OPERATIONS:

a. Grading: Finish to grades indicated within one-tenth of a foot.

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Provide sod in areas to be sodded as indicated and in accordance with the requirement specified in Section 02930, “Turf”. Grade areas to drain water away from structures and to provide suitable surfaces for mowing machines. Grade existing grades that are to remain but have been disturbed by the Contractor’s operations.

b. Spreading Topsoil: Comply with the requirements of Section 02930, “Turf”.

c. Disposition of Surplus Material: Surplus or other soil material not required or suitable for filling or backfilling shall be removed from Government property.

d. Pavement Repair: Do not repair pavement until trench has been backfilled and compacted as specified herein. As a minimum, maintain one-way traffic on roads and streets crossed by trenches.

3.9 FIELD QUALITY CONTROL

Test sand bedding for conformance to a specified requirements. Test bedding and backfill for moisture-density relations in accordance with JIS A 1210 as specified herein. Perform at least one of each of the required tests for each material provided. Perform sufficiently in advance of construction so as not to delay work. Provide additional tests as specified above for each change of source. Perform one density and moisture tests in randomly selected locations and in accordance with JIS A 1214.

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