8417 EVERGREEN WAY Geotech Report 2022-10-25

Geotechnical Engineering Report-Revised lierracon Proposed CFT Retail ■ Everett,Washington February 1, 2018 ■Terracon Project No. 81185002 EXECUTIVE SUMMARY A geotechnical exploration program has been performed for the proposed CFT Retail building located in Everett, Washington. Terracon's geotechnical scope of services included the advancement of 8 soil test borings to approximate depths of 6%2 to 211/2 feet below existing site grades. The site appears suitable for the proposed construction based upon geotechnical conditions encountered in the borings and our current understanding of the proposed development. The following geotechnical considerations were identified: • We encountered existing fill soil to depths of up to approximately 7 feet in our explorations in the area of the proposed CFT Retail building footprint. We recommend complete removal of the existing fill soil below the building pad and replacement with structural fill unless the owner is willing to accept the risk of unpredictable settlement response by leaving some of this soil in place. An allowable bearing pressure of 2,500 pounds per square foot(psf) can be used for shallow footings bearing on native material or structural fill extending to firm native soil. • Assuming the owner is willing to accept the risk of unpredictable settlement response by leaving some of the existing fill below the pavement section, we recommend scarification and recompaction of the upper 24 inches of pavement subgrade prior to construction of the recommended pavement sections. • The on-site soil contains a significant fraction of fines (silt passing the#200 mesh sieve) making the soil highly sensitive to moisture. However, the soil may be suitable for reuse as structural fill, provided the soil can be placed and compacted near the soil's optimum moisture content. Additional care should be taken to prevent an increase in soil moisture content. • The 2015 International Building Code (IBC) seismic site classification for this site is D. Close monitoring of the construction operations discussed herein will be critical in achieving the design subgrade support. We therefore recommend that Terracon be retained to monitor this portion of the work. This summary should be used in conjunction with the entire report for design purposes. It should be recognized that details were not included or fully developed in this section, and the report must be read in its entirety for a comprehensive understanding of the items contained herein.The section titled GENERAL COMMENTS should be read for an understanding of the report limitations. Responsive ■ Resourceful ■ Reliable