11030 7TH AVE SE 2018-01-02 MF Import

4D C". H a5yati HzH H H �l yNt� � z H17 OH HMO 04 n zH yyH rHH dw O H 0 Cj (n Mr. John McCoraghy April 28, 1989 Site Drainag Positive surface gradients should be provided to direct surface runoff away from the buildings towards suitable discharge facilities along the roadways. Perimeter foundation drains should be installed and tightlined away from apartment buildings. Roof gutter drains should be separately tightlined away from the structures. Adequate drainage measures should also be provided during construction of the pool. We recommend permanent drains around the pool which will allow dewatering around the pool when the pool has to be emptied and thus avoid uplift due to hydrostatic pressures on the pool bottom. Pavement Areas Any on -site roadway construction should be supported on a minimum of one foot of compacted structural fill. The upper twelve (12) inches of the pavement subgrade should be compacted to 95 percent of the maximum dry density (ASTM D-1557) although a compaction level of 99 percent is adequate for lower lifts. Regardless of the relative compaction, all subgrade areas should be in a stable, non -yielding condition prior to ,,aving. The pavement section for lightly loaded traffic areas should consist of two inches of Asphalt surfacing over four inches of Crushed Rock Base or three inches of Asphalt Treated Base (ATB). ,e Some settlements and pavement cracking may occur if the organic soils, topsoils, and fills present in the roadway area are not completely removed. 1 Site Preparation and Grading Groundwater seepage should be anticipated in any excavations made on the site. In order to intercept this seepage, we recommend that drainage ditches or interceptor drains be maintained around the work areas on both sides of the property. These ditches or drains should extend to a sufficient depth to intercept surface and subsurface flow and to carry it to the creek. The organic soils, topsoils and localized fills present across the site will be subject to '= ompression. Hence, settlements should be anticipated under applied loads. Therefore, these soils should be removed entirely from building pad and roadway areas, and other areas where structural fill is to be placed. These soils should be exported from the site or stockpiled for later use in non-structural landscape areas. Building pad areas should be over -excavated to remove the organic soils and to expose competent native glacial till or outwash sands and gravels. Foundations should bear on structural fill placed after the building pad has been over -excavated. We recommend that import materials to be used as structural fill be examined by the soils engineer prior to use. We suggest that import material to be used in wet conditions should contain less than 5% fines (material passing a #200 sieve in the portion passing the 3/4' sieve). Project No. T-1005