6525 HARDESON RD BASE FILE 2016-01-01 MF Import

f Intracorp August 25, 1997 Utilities E-3592-710 Page 4 Based on the soil conditions encc��ntered, the soils expected to be exposed by utility excavations should provide adequate support for utilities. Utility trench backfill is e primary concern in reducing the potential for settlement aiong utility alignments, particularly in pavement areas. It is important that each section of utility line be adequately supported in the bedding material. The materiai should be hand tamped to ensure support is provided around the pipe haunches. Fill should be carefully placed and hand tamped to about twelve inches above the crown of the pipe before heavy compaction equipment is brought into use. The remainder of the trench backfill should be placed in lifts having a loose thickness of less than twelve inches. The adequacy of site pavements is related in part to the condition of the underlying subgrade. To provide a properly prepared subgrade for pavements, the subgrade should be treated and prepared as described in the Site Preparation section of this report. This means at least the top twelve (12) inches of the subgrade should be compacted to 95 percent of the maximum dry density (per ASTM D-1557-911. It is possible that some localized areas of soft, wet or unstable subgrade may still exist after this process. Therefore, a greater thickness of structural fill or crushed rock may be needed to stabilize these localized areas. The following pavement section for lightly-loaded areas can be used: • Two inches of asphalt concrete (AC) over four inches of crushed rock base (CRB) material, or • Two inches of AC over three inches of asphalt treated base (ATB) material. Heavier truck-traffic areas will require thicker sections depending upon site usage, pavement life and site traffic. As a general ruie, the following sections can be considered for truck-trafficked areas: • Three inches of AC over six inches of CRB, or • Two inches of AC over four inches of ATB. Euth Con�uh�ntt. Inc.