1910 MERRILL CREEK PKY 2018-11-15

Intracorp E-3592-520 - September 23, 1998 Page 8 Site Drainaue Groundwater seepage was not encountered in the test pit excavations, therefore, it does not appear groundwater will present construction related issues while excavating for foundations or utilities. However, if groundwater seepage is encountered during construction, the bottom af the excavation should be sloped to one or more shallow sump pits. The collected water can then be pumped from these pits to a positive and permanent discharge, such as a nearby storm drain. Depending on the magnitude of such seepage, it may also be necessary to interconnect the sump pits by a system of connector trenches. During construction, the site must be graded such that surface water is directed off the site. Water must not be allowed to stand in areas where buildings, slabs or pavements are to be constructed. Loose surfaces should be sealed at night by compacting the surface to reduce the potential for moisture infiltration into the soils. Final site grades must allow for drainage away from the building foundations and tops of the steep descending slopes. The ground should be sloped at a gradient of three percent for a distance of at least ten feet away from the building, except in paved areas, which can be sloped at a gradient of one percent. Footing drains should be installed around the building perimeter, at or just below the invert of the footing, with a gradient sufficient to initiate flow. A typical detail is provided on Plate 3. Under no circumstances should roof downspout drain lines be connected to the footing drain system. All roof downspouts must be separately tightlined to discharge. Water should not be discharged adjacent to or over the top of the descending slopes. Cleanouts should be installed at strategic locations to allow for periodic maintenance of the footing drain and downspout tightline systems. Utility Trench Backfill Based on the soil conditions encountered, the soils expected to be exposed by utility excavations should provide adequate support for utilities. Utility trench backfill is a primary concern in preventing settlement along utility alignments, particularly in pavement areas. Therefore, it is important that each section of utility line be adequately supported in the bedding material, The material 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. A typical trench backfill section and compaction requirements for load supporting and non-load supporting areas is presented on Plate 4. Earth Coneultants, (nc.