711 112TH ST SE 7 ELEVEN Geotech Report 2018-01-02 MF Import

Subsurface Ecplomtion and Proposed 7-Eleven Property Geotrchnical Engineering Rrport 6verett, WashinRtan DestRn Recommendations including both dead and live loads. An increase of one-third may be usr for short-term wind or seismic loading. However, all rock- or CDF-filled trenches must �etrate to medium dense to very dense, natural sediments and no trenches should be founde :n or above loose, organic, or existing uncontrolled fill soils. In addition, all footinAs must be centered over the trenches. Continuous footings should have a minimum width of 14 inches for the one-story strucmres. Anticipated settlement of footings founded on approved rock- or CDF-filled trenches should be on the order of 1 inch. However, disturbed material not removed from footing venches prior to footing placement could result in increased setdements. All footing areas should be inspected by AESI prior to placing concrere [o verify that the trenches are undismrbed, the footings are centered, and that construction conforms with the tecommendations contained in this reNort. Such inspections may be required by the governing mur�icipaliry. Perimeter footing drains should be provided as discussed underthe section on Drainage Considerations. 9.3 Drilled Piers Foundations We anticipate that drilled piers will be necessary for support of the pump island's canopy foundation. Similar piers could also be used to penetrate the existing fill material and provide support for the buildings. Drilled piers consist of an open borehole, typically drilled with a truck-mounted auger, which is then filled wi�h concrete and reinforcing steel. Drilled piers are most efficient on sires where the soils do not cave when excavated. No caving was observcd at the time of our explorations. However, if caving occurs during the drill'eng process, the boreholes may need to be cased. Water entering the hole will need to be removed prior to placement of concrete. Alternatively, a tremie pipe or pump hose extending to the bottom of the hole may be used to displace the water with the concrete. Since the drilled piers are deeper than typical spread footing foundations, they can be designed to resist lateral forces (overturning) from transient wind and ceismic loads. For this case, drilled piers with a minimum diameter of 18 inches may be assigned the allowable vertical loads listed in Table l below. A qualificd structural engineer should determine the number of piers requi:ed and the maximum spacing betweeu each pier. Afarch /9, 200/ ASSOCIATED E�RTNSCIENCES SR7Pup � REIIA9J.Y11 � D nvr��i r m_ µ:n� P�ge 10 �