Specification__31_20_11_Earthwork.doc

10-01-12

SECTION 31 20 11

EARTHwork

PART 1 ‑ GENERAL

1.1: DESCRIPTION:

This section specifies the requirements for furnishing all equipment, materials, labor and techniques for earthwork including excavation, fill, backfill and site restoration.

1.2 DEFINITIONS:

A.

Unsuitable Materials:

1.

Fills: Topsoil, frozen materials; construction materials and materials subject to decomposition; clods of clay and stones larger than 75 mm (3 inches); organic materials, including silts, which are unstable; and inorganic materials, including silts, too wet to be stable.

2.

Existing Subgrade: Same materials as above paragraph, that are not capable of direct support of slabs, pavement, and similar items, with the possible exception of improvement by compaction or similar methods of improvement.

B.

Earthwork: Earthwork operations required within the construction area.

C.

Degree of Compaction: Degree of compaction is expressed as a percentage of maximum density obtained by the test procedure presented in ASTM D698.

D.

The term fill means fill or backfill as appropriate.

1.3 CLASSIFICATION OF EXCAVATION:

A.

Unclassified Excavation: Removal and disposal of pavements and other man-made obstructions visible on the surface; utilities, and other items including underground structures indicated to be demolished and removed; together with any type of materials regardless of character of material and obstructions encountered.

1.4 SUBMITTALS:

A.

Contractor shall submit procedure and location for disposal of unused satisfactory material. Proposed source of borrow material. Advance notice on the opening of excavation or borrow areas. Advance notice on shoulder construction for rigid pavements.

D.

Soil gradation and quality reports of proposed off site or on site fill material.

E.

Qualifications of the commercial testing laboratory or Contractor’s Testing facility shall be submitted.

1.5 APPLICABLE PUBLICATIONS:

A.

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

B.

American Nursery and Landscape Association (ANLA):

American Standard for Nursery Stock

C.

American Association of State Highway and Transportation Officials (AASHTO):

T99-10 Moisture-Density Relations of Soils Using a 2.5 kg (5.5 lb) Rammer and a 305 mm (12 inch) Drop

T180-10 Standard Method of Test for Moisture-Density Relations of Soils Using a 4.54-kg [10 lb] Rammer and a 457 mm (18 inch) Drop

D.

American Society for Testing and Materials (ASTM):

C33-03 Concrete Aggregate

D698-e1 Laboratory Compaction Characteristics of Soil Using Standard Effort

D1140-00 Amount of Material in Soils Finer than the No. 200 (75-micrometer) Sieve

D1556-00 Standard Test Method for Density and Unit Weight of Soil in Place by the Sand-Cone Method

D1557-09 Laboratory Compaction Characteristics of Soil Using Modified Effort

D2167-94 (2001) Standard Test Method for Density and Unit Weight of Soil in Place by the Rubber Balloon Method

D2487-06 Standard Classification of Soil for Engineering Purposes (Unified Soil Classification System)

D6938-10 Standard Test Methods for Density of Soil and Soil-Aggregate in Place by Nuclear Methods (Shallow Depth) E.

Standard Specifications of Maryland State Department of Transportation, latest revision.

PART 2 ‑ PRODUCTS

2.1 MATERIALS:

A.

Fills: Materials approved from offsite sources having a minimum dry density of 1760 kg/m3 (110 pcf), a maximum Plasticity Index of 6, and a maximum Liquid Limit of 30.

B.

Granular Fill:

1.

Granular fill shall consist of clean, poorly graded crushed rock, crushed gravel, or uncrushed gravel. Fine aggregate grading shall conform to ASTM C33 with a maximum of 3 percent by weight passing ASTM D1140, No. 200 sieve and no more than 2 percent by weight passing the No. 4. Coarse aggregate shall be Maryland Department of Transportation Size 57, 67, or 7. Maryland Department of Transportation Crusher Run Aggregate CR-6 is specifically prohibited.

C.

Requirements For Offsite Soils: Offsite soils brought in for use as backfill shall be tested for TPH, BTEX and full TCLP including ignitability, corrosivity and reactivity. Backfill shall contain less than 100 parts per million (ppm) of total hydrocarbons (TPH) and less than 10 ppm of the sum of Benzene, Toleune, Ethyl Benzene, and Xylene (BTEX) and shall not fail the TCLP test. TPH concentrations shall be determined by using EPA 600/4-79/020 Method 418.1. BTEX concentrations shall be determined by using EPA SW-846.3-3a Method5030/8020. TCLP shall be performed in accordance with EPA SW-846.3-3a 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. Material shall not be brought on site until tests have been approved by the Contracting Officer.

D. Fertilizer: (5-10-5) delivered to site in unopened containers that clearly display the manufacturer's label, indicating the analysis of the contents.

E. Seed: Grass mixture comparable to existing turf delivered to site in unopened containers that clearly display the manufacturer's label, indicating the analysis of the contents.

PART 3 ‑ EXECUTION

3.1 EXCAVATION:

A.

Shoring, Sheeting and Bracing: Shore, brace, or slope to its angle of repose banks of excavations to protect workmen, banks, adjacent paving, structures, and utilities, in compliance with OSHA requirements.

1.

Extend shoring and bracing to the bottom of the excavation. Shore excavations that are carried below the elevations of adjacent existing foundations.

2.

If the bearing of any foundation is disturbed by excavating, improper shoring or removal of shoring, placing of backfill, and similar operations, provide a concrete fill support under disturbed foundations, as directed by the Contracting Officer, at no additional cost to the Government. Do not remove shoring until permanent work in excavation has been inspected and approved by the Contracting Officer.

B.

Excavation Drainage: Keep excavations free of water and subgrades dry, firm, and undisturbed until approval of permanent work has been received from the Contracting Officer. When subgrade has been disturbed by water, remove the disturbed material to firm undisturbed material after the water is brought under control. Groundwater flowing toward or into excavations shall be controlled to prevent sloughing of excavation slopes and walls, boils, uplift and heave in the excavation and to eliminate interference with orderly progress of construction.

C.

Earthwork:

1.

Excavation shall be accomplished as required by specifications.

2.

Excavate excavations to solid undisturbed subgrade.

3.

Remove loose or soft material to solid bottom.

4.

Fill excess cut under footings or foundations with 25 MPa (3000 psi) concrete.

3.

Do not tamp earth for backfilling in footing bottoms, except as specified.

3.2 FILLING AND BACKFILLING:

A.

General: Do not fill or backfill until all debris, unsatisfactory soil materials, obstructions, and deleterious materials have been removed from the excavation. Use excavated materials or borrow for fill and backfill, as applicable. Do not use unsuitable excavated materials.

B.

Placing: Place material in horizontal layers not exceeding 8 inches in loose depth and then compacted. Do not place material on surfaces that are muddy, frozen, or contain frost.

C.

Compaction: Use approved equipment (hand or mechanical) well suited to the type of material being compacted. Do not operate mechanized vibratory compaction equipment within 10 feet of new or existing building walls without the prior approval of the Contracting Officer. Moisten or aerate material as necessary to provide the moisture content that will readily facilitate obtaining the specified compaction with the equipment used. Compact each layer to not less than 95 percent of the maximum density determined in accordance with the following test method ASTM D698 or D1557 Method A.

D.

Borrow Material: Borrow material shall be from a site off of Government property.

3.3 GRADING:

A.

General: Uniformly grade the areas within the limits of this section, including adjacent transition areas. Smooth the finished surface within specified tolerance. Provide uniform levels or slopes between points where elevations are indicated, or between such points and existing finished grades. Provide a smooth transition between abrupt changes in slope.

B.

Place coarse aggregate fill under concrete slabs on grade tamped, leveled and compacted. The finished thickness of the fill shall be 12 inches.

3.4 LAWN AREAS:

A. General: Harrow and till to a depth of 4 inches, new lawn areas. Establish existing or design grades by dragging or similar operations. Do not carry out lawn areas earthwork out when the soil is wet so that the tilth of the soil will be destroyed. Plant bed must be approved by Resident Engineer before seeding or sodding operation begins.

B. Finished Grading: Begin finish grading after rough grading has had sufficient time for settlement. Scarify subgrade surface in lawn areas to a depth of 4 inches. Apply topsoil so that after normal compaction, dragging and raking operations (to bring surface to finish grades) there will be a minimum of 4 inches of topsoil over all lawn areas; make smooth, even surface and true grades, which will not allow water to stand at any point. Shape top and bottom of banks to form reverse curves in section; make junctions with undisturbed areas to conform to existing topography.

C. Fertilizing: Incorporate fertilizer into the soil to a depth of 4 inches at a rate of 25 pounds per 1000 square feet.

D. Seeding: Seed at a rate of 4 pounds per 1000 square feet and accomplished only during periods when uniform distribution may be assured. Lightly rake seed into bed immediately after seeding. Roll seeded area immediately with a roller not to exceed 150 pounds per foot of roller width.

E. Watering: Maintain watering on the areas until the grass is established.

3.5 Disposal of unsuitable and excess excavated material:

A.

Disposal: Remove surplus satisfactory soil and waste material, including unsatisfactory soil, trash, and debris, and legally dispose of it off Government property.

B.

Remove from site and dispose of any excess excavated materials after all fill and backfill operations have been completed.

3.6 CLEAN‑UP:

Upon completion of earthwork operations, clean areas within contract limits, remove tools, and equipment. Provide site clear, clean, free of debris, and suitable for subsequent construction operations. Remove debris, rubbish, and excess material from Government property.

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