406 SE EVERETT MALL WAY BASE FILE 2018-01-02 MF Import

Auto Mall Associates May 16, 1986 E-2976 Page 3 performed during construction of the existing building resulted in cuts along the eastern portion of the existing facility with fills along the western margin. Based on topography presented on the site plan, ECI anticipates that the existing fills may be up to five feet in thickness. Groundwater No groundwater was encountered during the excavation of our test pits. However, during the rainy season ECI anticipates that some groundwater may be present. Groundwater on this site will occur as a perched groundwater table. This occurs as precipitation and runoff, upon infiltrating the looser near surface soils encounters and subsequently becomes perched above the relatively impermeable till soils. DISCUSSION AND RECOMMENDATIONS General Based on soils encountered in our test pits, it is ECI's rofessional opinion that the proposed facility may be de` — �elope_a as pla iea. The structures may be supported on conventional shallow spread and/or continuous footings bearing on either competent native soils or on structural fill. Placement of footings on the dense till soils encountered within four feet of existing grades will allow the use of higher bearing pressures and hence smaller footings for columns. The eastern building is planned to be almost entirely in cut and dense till soils should be present close to the proposed floor elevation. The western building with the finished floor at Elev. 599 will be on fill at its western portion. The on -site soils may be used as structural. fill, if the moisture content is close to optimum moisture. However, it should be noted that the upper on -site soils were wet and contain a high amount of fines that will make them difficult to work in their present condition. The glacial tills also contain high amounts of fines that will make them difficult to compact during periods of sustained precipitation. Finally, it should be noted that existing facilities along the western margin of the site precluded the excavation of test pits. ECI should be retained during construction to verify subsurface conditions in this area. The following sections contain our recommendations in greater detail. Foundations The proposed structure may be supported on conventional conti- nuous and spread footings bearing on the competent native soils or Earth Consultants., Inc.