Excavation and backfilling specifications, 10th Ave Tunnel

NYC 9/11 Public Portal Document

( 4. Removal of shoring and bracing where applicable, and as directed, B. Backfill Material: Except where concrete is specified for backfill at structures, use select backfill material for backfill up to the elevation below future yard level as indicated on the Drawings. Use common backfill material for all other backfill. I

C. Placement and Compaction: ;f 1. Place backfill materials in layers 8" in loose depth. Before compaction, moisten or aerate each layer as necessary to provide the optimum moisture content*- Compact each layer to required percentage of maximum density as specified. Do not place backfill material on surfaces that are muddy, or contain frost. 2. Backfill materials shall be installed evenly on opposing sides of structues to prevent wedging action from occurring. A I; 3. Over tunnel roof slabs, place backfill in uniform lifts over the full area or as approved. Exercise care to ensure maintenance of the integrity of the waterproofing. Backfilling shall not be started over t roof slabs until concrete has achieved design strength unless otherwise permitted by the Engineer. f D. Grading: Carry backfill up to approximate existing grade elevations. Rough : I grade the area to drain away from the structure and to prevent ponding. E. Concrete Backfill: Place and vibrate in accordance with applicable ri requirements of paragraph 3.06 of Section 03310. « 3.14 COMPACTION . V : Hi i I'i A. General: The Contractor shall control compaction during construction to provide minimum percentage of density specified, es determined per ASTM D 1557, Method C. Field testing will be conducted by the Engineer in accordance with ASTM 0 1556 or D 2922. The Contractor shall conduct such field tests for his own purposes as may be required to ensure the prosecution of the work 1n accordance with these Specifications. i f B. Density: Compact each layer of select backfill material to not less than 95 percent of maximum density. Compact each layer of common backfill material to 90 percent of maximum density. !l! C. Moisture Control: 1. Where layer of material must be moisture conditioned before compaction, uniformly apply water to surface of layer of placed material, in such manner as to prevent free water appearing on surface during or subsequent to compaction operations. 2. Remove and replace, or scarify and air dry soil material that is too wet to permit compaction to specified density. I

Contract 02220-13 Excavation and 1-02-21064-0-0 Backfilling

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NYC-WTC_000165820