Earthfill CS_254.doc

Construction Specification 254—Earthfill

1.

Scope

The work shall consist of the construction of all earthfill structures and earth backfills required by the drawings and specifications.

Earthfill is composed of natural earth materials that can be placed and compacted by construction equipment operated in a conventional manner.

Earth backfill is composed of natural earth material placed and compacted in confined spaces or adjacent to structures (including pipes) by hand tamping, manually directed power tampers or vibrating plates or their equivalent.

2.

Material

Fill material shall be obtained from required excavations and/or designated borrow areas. The selection, blending, routing, and disposition of material in the various fills shall be subject to approval by the engineer.

Fill material shall be free of sod, brush, roots, trash, or other objectionable material. Rock particles larger than 6 inches shall be removed prior to compaction of the fill.

3.

Foundation preparation

The earth foundation surface shall (after stripping and before placing the first layer of earthfill) be graded to remove surface irregularities, be scarified and moisture-conditioned to a minimum depth of 2 inches to facilitate compaction and a good bond with the earthfill. The moisture content of the foundation materials at the time of compaction shall be the same as the earthfill to be placed on the foundation.

No embankment material shall be placed upon the earth surfaces of excavations, foundation preparation, or previous embankment when such surfaces have dried sufficiently to form shrinkage cracks. Such earth surfaces being readied for embankment shall have all loose, hard, dry, and cracked material removed and then scarified and moisture conditioned to a minimum depth of 2 inches.

4.

Placement

Earthfill shall not be placed upon a frozen surface nor shall snow, ice, or frozen material be incorporated into the earthfill matrix.

Earthfill shall be placed in approximately horizontal layers starting at the lowest point in the foundation. The earthfill materials shall be placed in nearly horizontal layers not exceeding 9 inches before compaction or as shown on the drawings. Materials placed by dumping in piles or windrows shall be spread uniformly to not more than the specified thickness before being compacted.

Machine compaction shall be accomplished by the controlled movement of hauling and spreading equipment over the fill area. Every point on the surface of each lift shall be traversed by not less than one tread track of the equipment.

Hand compaction shall be required in areas inaccessible to heavy equipment. The hand-compacted fill shall be compacted by hand tamping or manually directed power tampers or plate vibrators. The backfill shall consist of clay material (CL or SC) free of stones larger than 2 inches. The fill shall be placed in layers not more than 4 inches thick before compaction. Such protective measures as necessary shall be taken to ensure that the fill does not dry sufficiently to form cracks after placement.

5.

Control of moisture content

During placement and compaction of earthfill and earth backfill, the moisture content of the material being placed shall be sufficiently moist to prevent dusty conditions. The material will also be sufficiently dry to be workable (without excessive rutting of the compacted surface by the earthmoving equipment). Tracks from the earthmoving equipment should not exceed one-half of the compacted fill layer depth. The top surface of the preceding layer of fill shall have adequate moisture to permit suitable bonding with the next layer of fill prior to the placement of additional fill.

6.

Measurement and payment

For items of work for which specific lump sum prices are established in the contract, the quantity of work will not be measured for payment. Payment for this item will be made at the contract lump sum price and will constitute full compensation for completion of the work.

For items of work for which specific unit prices are established in the contract, the volume of earthfill is determined from the design dimensions as staked in the field and computed to the nearest cubic yard by the method of average cross sectional end areas. The design dimensions shall be the measured surface of the foundation prior to the stripping of vegetation and the specified neat lines of the constructed surface unless otherwise specified in section 7. No deduction in volume will be made for embedded items such as (but not limited to) conduits and water control structures.

Compensation for any item of work described in the contract (but not listed in the bid schedule) is included in the payment for the item of work to which it is made subsidiary. Such items and the items to which they are made subsidiary are identified in section 7 of this specification.

7. Items of work and construction details

Items of work to be performed in conformance with this specification and the construction details are:

Bid Item 2 - Earthfill, Auxiliary Spillway Repair (1) This item shall consist of the construction of the machine-compacted fill required to replace and/or restore the material eroded from the auxiliary spillway. The completed work shall conform to the lines and grades of the auxiliary spillway as shown on the drawings.

(2) Fill material will be obtained on-site from the locations as shown on the plans. Material deposited from the eroded areas may be recovered and used as fill within one foot of the finished surface. As allowable, recovered material shall be used first before proceeding to the designated borrow area. Rock larger than 6 inches will be allowed if compaction can be accomplished and does not hinder construction operations.

(3) Compaction shall be accomplished by two passes entirely over each 9-inch lift of fill material below the topsoil and over each 12-inch lift of topsoil by the machine hauling or pushing the fill material. Foundation surfaces shall be scarified a minimum of 4 inches deep prior to placement of fill material. Vertical foundation surfaces shall be worked down adequately prior to placement of fill to ensure proper bonding with the fill material.

(4) For items of work for which specific lump sum prices are established in the contract, the quantity of earthfill will not be measured for payment. Payment for earthfill will be made at the contract lump sum price and will constitute full compensation for all labor, equipment, tools, and all other items necessary and incidental to the completion of the work.

(5) Payment will constitute compensation for the following related subsidiary items:

(a) Excavation, Outlet Channel - Construction Specification 255 (b) Excavation, Borrow - Construction Specification 255 (c) Pollution Control Measures - Construction Specification 251

NRCS – March 2009

254-1 KS –Big Caney Watershed District EWP, FRD 12