02322 Excavation and Fill for Structures Worland Hazmat Building.docx

SECTION 02322

EXCAVATION AND FILL FOR STRUCTURES

PART 1 – GENERAL

1.1 SCOPE OF WORK:

A. The work included under this Section consists of furnishing material and equipment, and performing all labor necessary for excavating, backfilling, filling and compaction of areas to be occupied by the facilities to be constructed.

B. Plan for Excavation: Prior to commencing the excavation, the Contractor shall submit a plan of his proposed operations to the Contracting Officer for approval. The Contractor shall consider, and his plan for excavation shall reflect, existing utilities that are to remain, the equipment and methods to be employed in the excavation.

1.2 QUALITY ASSURANCE

A. Contractor shall notify Wyoming One-Call at least 48 hours prior to any excavation

PART 2 – PRODUCTS

2.1 MATERIALS

A. Structural Fill: Structural fill shall consist of an inorganic, non-plastic, granular soil containing less than 10 percent material passing the No. 200 mesh sieve (relatively clean sand or crushed limerock with a 2-inch max. particle size) with a Unified Soil Classification of GP, GW, SP, SP-GM, SW-SM or SP-SM.

B. Ballast Rock: Ballast rock shall be composed of hard, durable, sound pieces having a specific gravity of not less than 2.65. It shall be crushed rock conforming to the following gradation:

C. Suitable Backfill Material: Backfill material shall be clean and free from all organic material, clay, marl or unstable materials, debris, lumps, or broken paving. No rocks or stones larger than 6-inches in diameter shall be allowed in any backfill. Material for backfill may be material resulting from excavation, if suitable by the Contracting Officer.

D. Select Backfill Material: Select backfill material specified herein shall meet all the general requirements for backfill material set forth above, and in addition, shall be free of any rocks or stones larger than 2 inches in diameter. Select backfill material may be material resulting from trench excavation, if suitable by the Contracting Officer, carefully selected to comply with these requirements.

PART 3 - EXECUTION

3.1 PREPARATION:

A. Clearing: The construction site shall be cleared of all obstructions and vegetation, including large roots and undergrowth, within 5 feet of the lines of excavation. All debris created by this clearing operation shall be hauled from the site and disposed of by the Contractor.

B. Removals: Complete all removals within the lines of excavation prior to beginning excavation. Where required all existing shrubbery, trees, grass, fences, structures, sidewalks, curbs, utility poles, or structures subject to damage resulting from the excavation should be transplanted, relocated, braced, shored, or otherwise protected and preserved.

3.2 EXCAVATION

A. The Contractor shall perform all excavation of every description and of whatever substances encountered, to the dimensions and depths shown on the drawings and as required for construction. All excavations shall be made by open cut.

B. When the walls of the excavations are to be kept vertical and in order to protect the safety of workmen, the general public, this or other work or structures, or excavation walls, or pipe installation including materials encountered in the excavation which have a tendency to slough or flow into the excavation, undermine the banks, weaken the overlying strata, or are otherwise rendered unstable by the excavation operation shall be retained by steel sheeting, stabilization, grouting or approved methods.

C. The Contractor shall maintain the bottom of the excavation firm and dry and maintain an elevation of the water one foot below the concrete to be placed, by use of pumps, tremie or other acceptable methods.

D. The trench sides may be sloped to a suitable angle of repose of the excavated material.

E. Excavated material shall be stored and disposed of in such a manner that they will not interfere unduly with traffic on public streets and sidewalks. In congested area, such materials, cannot be stored adjacent to the trench nor used immediately as backfill, shall be removed to convenient places of storage. If any material is creating a public hazard or other unsafe condition, it shall be removed immediately to a storage area.

F. Materials suitable for use as backfill may be hauled to and used in areas where not enough suitable material is available from the excavation. Material unsuitable for use in backfill shall be removed promptly and disposed of by the Contractor. Any pockets of organic matter, concrete or other unsuitable material encountered in the excavation shall be removed and replaced with material satisfactory to the Contracting Officer.

3.3 DEWATERING

A. Any water which accumulates int eh excavations shall be removed promptly. Pumps and engines for dewatering systems shall be operated with mufflers.

B. Where applicable, the Contractor shall be required to obtain all necessary permits approving the location and proposed method of disposal before discharging water from any excavation into any existing drainage.

3.4 BACKFILL

A. The excavation shall then be brought to the structures bottom elevation by placing and compacting 6-inch layers of fill to 95 percent of maximum density as determined by AASHTO T-180. Structural fill shall be supplied by the Contractor except as may otherwise be carefully selected from excavated material. Backfill around new structures up to the concrete base shall be material not exceeding 6-inches in diameter and shall be compacted in layers not exceeding 9 inches. Each layer shall be compacted with a powered hand tamper, or other approved method to at least 98% of maximum density as determined by AASHTO T-180.

PART 4: MEASUREMENT AND PAYMENT

4.1 METHOD OF MEASUREMENT

A. Units: The work described in this section will be measured and paid for on a lump sum basis.

4.2 BASIS OF PAYMENT

A. Payment: Prices and payment will be full compensation for the work described in this section. Payment will be made under:

Pay Item Pay Unit

02322(01) Earthwork Cut and Fill Cubic Yards

END OF SECTION

EXCAVATION AND FILL FOR STRUCTURES

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