1505 112TH ST SW 2018-01-02 MF Import

GEOTF.CEMCAL ENGINEERING STUDY Wells Pae 7 t Development Corporation July 27, 1992 Pave 7 The lite should be graded such that suface water is directed off the site.. Water should not be allowed to stand in any area where buildings, slabs or pavements are to be constructed. During construction, loose surfaces should be sealed at night by compacting the surface to reduce the potential for moisture infiltration into the soils. Final site grades should allow for drainage away from the building founuations. The ground should be sloped at a gradient of three percent for a distance of at least ten feet away from the buildings in landscape areas. In pavement areas, this may be reduced to two percent. All backfdl associated with utility line trenches and demolition operations should be spread, watered or aerated as required, thoroughly mixed to a uniform near -optimum moisture condition, and compacted by mechanical means in approximate six-inch thick lifts. The degree of compaction obtained should be at least 90 percen! of the ASTM D-1557-78 laboratory test standard. All fill or bacldill operations should be subjert to compaction control inspection and testing by this office. The adequacy of site pavements is related in part to the conditien of the underlying subgrade. To provide a properly prepared subgrade for pavements, we recommend the subgrade be treated and prepared as described in the Site Preparation section of this report. This means at least the lap twelve (12) inches of the subgrade should be compacted to 95 percent of the maximum dry density (per ASTM D-1557-78). It is possible that some localized areas of soft, wet or unstable subgrade may still tzdst after this process. Therefore, a greater thickness of structural fill or crushed rock may be needed to stabilize these localized areas. The following pavement sections are recommended for lightly-Iaded areas consisting of parking stalls experiencing 100 cars: Two inches of Asphalt Concrete (AC) over four inches of Crusied Rock Base (CRB) material, or Two inches of AC over two inches of Asphalt Treated Base (ATB) material. The following pavement sections are recommended for heavier truck -traffic areas consisting primarily of various roadways subjected to a minimum daily traffic of I,000 cars and 5 111,000 pound single axle load trucks: • Three inchr—, of AC over six inches of CRt3, or • Two inches of AC over four inches of ATB. Earth Consultants. Inc.