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H. Excavation for Trenches: Dig trenches to the uniform width required for particular item to be installed, sufficiently wide to provide ample working room. Provide minimum 6 in. clearance on each side of pipe or conduit. 1. Excavate trenches to depth indicated or required for indicated flow lines and invert elevations. 2. Where rock is encountered, carry excavation 6 in. below scheduled elevation and backfill with a 6 in. layer of crushed stone or gravel prior to installation of pipe. 3. For pipes or conduit 5 in. or less, excavate to indicated depths. Hand excavate bottom cut to accurate elevations and support pipe or conduit on undisturbed soil. 4. For pipes or conduit 6 in. or larger, tanks and other work indicated to receive subbase, excavate to subbase depth indicated, or, if not otherwise indicated, to 6 in. below bottom of work to be supported. 5. Except as otherwise indicated, excavate for exterior water-bearing piping so top of piping is minimum 3'-0" below finished grade. 6. Grade bottoms of trenches as indicated, notching under pipe bells to provide solid bearing for entire body of pipe. Do not backfill trenches until tests and inspections have been made and backfilling authorized by Engineer. 3.02 COMPACTION A. Areas to be compacted shall be moistened and compacted by either rolling, tamping or any other approved method by the Engineer in order to obtain the desired density. The Contractor shall inspect all compacted areas prior to further construction operations to ensure that satisfactory compaction has been obtained. All backfill adjacent to structures and pipes, shall be compacted to a density of not less than 100 percent of the maximum density as determined by AASHTO T-99. Density tests are required, such tests shall be made as directed by the Engineer at the expense of the Contractor. The Contractor shall instruct the testing laboratory to forward copies of all test reports to the Engineer. B. Remove and replace, or scarify and air dry, soil material that is too wet to permit compaction to specified density. 3.03 BACKFILL AND FILL A. Place specified soil material in layers to required subgrade elevations: 1. In excavations, use satisfactory excavated or borrow material. 2. Under grassed areas, use satisfactory excavated or borrow material. 3. Under walks and pavements, use subbase material, or satisfactory excavated or borrow material, or combination of both. Place shoulders along edges of subbase course to prevent lateral movement with satisfactory excavated or borrow material. 4. Under steps, use subbase material. 5. Under building slabs, use drainage fill material. 08/12 02200-3 11-4179