3620 36TH PL NE 2018-01-02 MF Import

Table 1. Recommended Preload Height n.Siructurc r' Preload Height (feet) °: Compost Systems I ane 2 3 Compost System 3 8 Tipping Building 9 Office Building / Scale 5 Grinder Area 5 The preload height is the thickness of the preload fill that is placed above the finished grade elevation. The crest of the preload should extend laterally at least 5 feet beyond the footprint of each structure in each direction. It may be beneficial to expand the preload area(s) in case the locations of structure(s) are expected to move. As shown, an 8-foot preload of import granular soil should be placed on compost system Nos. 1 and 2. Each compost system will need roughly 32,000 cubic yids of preload fill, assuming 1 H:1 V side slopes. We recommend that the preload fill be placed after the structural fill pad for each structure is constructed by (1) placing the geotextile separator over a suitably prepared smooth subgrade, and (2) placing at least 2 feet of properly compacted structural fill below structural elements. We recommend that the compacted structural fill extend to the planned finished floor elevation to account for settlement. i The preload fill should consist of structural fill quality material compacted only to the extent necessary to support construction equipment. Side slopes should be planned no steeper than IHA V. The r preload surface should be crowned slightly to promote drainage of surface water. 4.3.2 Settlement Magnitude and Rate We estimate settlement due to the IV2 to 4%2 feet of fill that will be placed to raise site grades will be on the order of 2 to 6 inches, depending on the thickness of compressible soil (see Figure 4). We estimate t that with the addition of the 8-foot high preload for compost system Nos. 1, 2, and 3, the settlement will increase an additional 4 to 8 inches. Therefore, we estimate the total settlement in the thinner (6 feet) and thicker (20 feet) compressible soil areas to range from about 6 to 14 inches, respectively, for the i' combination of site grading and preload placement. We estimate that approximately 4 to 6 inches of settlement will occur due the construction of the tipping building preload fill and about 3 to 5 inches for the office building preload. The estimated settlement assumes that the soils have not been previously preloaded. However, we anticipate that some preloading of various portions of the site has occurred due to past logging activities and possible stacks of logs and wood products. Therefore, the estimated settlement magnitudes may vary substantially based on previous preloaded areas and due to the thickness of the underlying compressible soils. The estimated time for the settlement to occur is 6 to 8 weeks, but the actual duration of preloading should be based on settlement readings. The thicker compressible silt layers will require more time to consolidate and will likely be on the 8 week end of this range. The consolidation process could be accelerated by placing a surcharge fill on top of the preload fill. This may be desirable where thick deposits of silt exist under compost systems Nos. I and 2 as shown on Figure 4 (north -central area, , 0 G e o E n 9 i n e e r s 15 File No. 10615-001-02/123003