3617 UPLAND AVE Geotech Report 2025-03-28

GeoTest Services, Inc. April 15, 2021 3617 Upland Avenue, Everett,WA Project No. 21-0375 accounted for during the design life of the project, and the proposed structure should be designed to resist earthquake loading using appropriate design methodology. For structures designed using the seismic design provisions of the 2018 International Building Code, the medium dense to dense Transitional Beds underlying the site is classified as Site Class D, according to ASCE 7-16.The structural engineer should select the appropriate design response spectrum based on Site Class D soil and the geographical location of the proposed construction. Foundation Support Foundation support for the proposed developments can be established via continuous or isolated spread footings founded on firm and unyielding, remedially compacted Transitional Beds, or on properly compacted structural fill placed directly over these soils. GeoTest recommends that qualified geotechnical personnel confirm that suitable bearing conditions have been reached prior to placement of structural fill or foundation formwork. To provide proper support, GeoTest recommends that existing topsoil, existing fill (if present), and/or loose upper portions of the native soil be removed from beneath the building foundation areas. Dense, native soils are unlikely to require much preparation. However, if footings or structural fill will be placed atop previously placed fill or native Transitional Beds at depth, the surface should be compacted to a firm and unyielding condition with a smooth-drum roller, hoe- pack, or a similar piece of construction equipment. Once suitable bearing conditions have been confirmed,then foundations can bear directly on native soils or on properly compacted structural fill as described in the Fill and Compaction section of this report. Continuous and isolated spread footings should be founded 18 inches, minimum, below the lowest adjacent final grade for freeze/thaw protection. The footings should be sized in accordance with the structural engineer's prescribed design criteria and seismic considerations. Allowable Bearing Capacity Assuming the above foundation support criteria are satisfied, continuous or isolated spread footings founded directly on remedially compacted,firm and unyielding, native Transitional Beds or on compacted structural fill placed directly above these soils may be proportioned using a net allowable soil bearing pressure of 2,000 pounds per square foot (psf). The 'net allowable bearing pressure' refers to the pressure that can be imposed on the soil at foundation level. This pressure includes all dead loads, live loads, the weight of the footing, and any backfill placed above the footing. The net allowable bearing pressure may be increased by one-third for transient wind or seismic loads. 9