1610 SE EVERETT MALL WAY Geotech Report 2022-10-25

Subsurface Exploration, Geologic Hazard, and Krebs Property Preliminary Geotechnical Engineering Report Everett, Washington Preliminary Design Recommendations 10.0 FOUNDATIONS 10.1 Allowable Soil Bearing Pressure Spread footings may be used for building support when founded either directly on the medium dense to very dense, natural glacial sediments, or on structural fill placed over these materials, as described under the Site Preparation and Structural Fill sections of this report. For footings founded either directly upon the medium dense to very dense till, or on structural fill as described above, we recommend that an allowable bearing pressure of 2,500 pounds per square foot (psf) be used for design purposes, including both dead and live loads. Sediments suitable for foundation support were generally encountered in our explorations at depths of approximately 1.5 to 3 feet. If higher bearing pressures are needed, a value of 4,000 psf may be used in areas where all footings are placed entirely on the undisturbed dense to very dense lodgement till. Dense to very dense lodgement till sediments were encountered in our explorations at depths of approximately 2.5 to 4 feet. An increase of one-third may be used for short-term wind or seismic loading. 10.2 Minimum Footing Embedment Perimeter footings for the proposed buildings should be buried a minimum of 18 inches into the surrounding soil for frost protection. No minimum burial depth is required for interior footings; however, all footings must penetrate to the prescribed stratum, and no footings should be founded in or above loose, organic, or existing fill soils. 10.3 Footings Adjacent to Cuts The area bounded by lines extending downward at 1H:1V from any footing must not intersect another footing or intersect a filled area that has not been compacted to at least 95 percent of ASTM:D 1557. In addition, a 1..5H:1V line extending down from any footing must not daylight because sloughing or raveling may eventually undermine the footing. Thus footings should not be placed near the edges of steps or cuts in the bearing soils. 10.4 Footing Settlement Anticipated settlement of footings founded as described above should be on the order of 1 inch or less. However, disturbed soil not removed from footing excavations prior to footing placement could result in increased settlements. 10.5 Footing Subgrade Bearing Verification All footing areas should be observed by AESI prior to placing concrete to verify that the exposed soils can support the design foundation bearing capacity and that construction February 13, 2007 ASSOCIATED EARTH SCIENCES, INC. TJP/ld-KE070013A1-Projects120070023IKE1WP Page 11