6202 ASSOCIATED BLVD Geotech Report 2022-10-25

Proposed Everett Warehouse Project No. 2152.01 March 5, 2019 worker access is necessary. The cuts should be adequately sloped, shored, or supported to prevent injury to personnel from local sloughing and spalling. The excavation should conform to applicable Federal, State, and Local regulations. According to Chapter 296-155, Part N of the Washington Administrative Code (WAC), the contractor should make a determination of excavation side slopes based on classification of soils encountered at the time of excavation. For planning purposes, we recommend temporary excavations be planned no steeper than 1H:1V (horizontal to vertical). Temporary cuts may need to be constructed at flatter angles based upon the soil moisture and groundwater conditions at the time of construction. Adjustments to the slope angles should be determined by the contractor at that time. Temporary excavations that extend below the groundwater table will not be adequately stable unless dewatered. Groundwater levels should be maintained a minimum of two feet below the bottom of temporary excavations. We recommend that all permanent cut or fill slopes (excluding stormwater ponds) constructed in native soils or with imported structural fill be designed at a 2H:1V (Horizontal:Vertical) inclination or flatter. All permanent cut and fill slopes should be adequately protected from erosion both temporarily and permanently. We do not expect stormwater ponds for this project. If the slopes are exposed to prolonged rainfall before vegetation becomes established, the surficial soils will be prone to erosion and possible shallow sloughing. We recommend covering permanent slopes with a rolled erosion protection material, such as composite straw or coir matting or Curlex II, if vegetation has not been established by the regional wet season (typically November through May). Foundations Based on our analyses, conventional, shallow spread footings appear feasible for support of building and other foundation loads provided that the foundation subgrades are prepared in accordance with this report. Recommendations for shallow spread footings are provided below. Shallow Foundation Depth and Width For frost protection, the bottom of all exterior footings should bear at least 18 inches below the lowest adjacent outside grade, whereas the bottoms of interior footings should bear at least 12 inches below the surrounding slab surface level. However, finished grade along the north and west sides of the building will slope down and away from the building. Sloping ground conditions adjacent to footings will reduce the allowable bearing pressure. Additionally, future excavations along the west side of the building that may be required for maintenance or other reasons would be limited as such excavations may destabilize footings. Therefore, for the west building line, we recommend that bottom of footing elevations be located no higher than proposed finished grades along the adjacent drive isle west of the building. For the north building line, we recommend bottom of footings be established no higher than elevation 424 feet. From the northwest corner of the building, the bottom of footings should step up incrementally Page 11