1010 N BROADWAY STARBUCKS 2025-07-24

Geotechnical Engineering Report � Y,��o Broadway& 10th Starbucks E Everett, WA n January 9, 2014 Terracon Project No. 81135080 EXECUTIVE SUMMARY Terracon has completed a geotechnical engineering evaluation for the proposed construction of a new Starbucks coffee shop at the project site. Our scope of work included exploratory borings, limited laboratory soil testing, geotechnical analysis, and preparation of this report. Based on our findings, we have derived the following geotechnical conclusions and recommendations: • Subsurface Conditions: The site appears to be mantled by about 3 feet of medium dense to dense silty sands with gravel, which we interpret as previously placed fill material. This fill is underlain by a native glacial till deposit comprising dense to very dense silty sands with gravel to gravelly silty sands. Groundwater was not encountered during our site exploration program, though the potential for perched groundwater above the glacial till exists during periods of heavy rainfall. m Building Support: The proposed building can be supported by conventional spread footings. However, due to the presence of fill soils mantling the site, we recommend complete removal of all fill below footings. Building footings could bear on the exposed, dense to very dense glacial till or on new structural fill extending to native soils. E Floor Support: A conventional slab-on-grade floor can be used within the proposed building if the floor subgrades are properly prepared and the existing fill material below the building is removed and replaced with structural fill. • Earthwork Considerations: The on-site soils are moderately silty, which renders them sensitive to moisture conditions and difficult to compact when wet. As such, earthwork should be performed during periods of dry weather or increased quantities of imported and exported soils should be anticipated. ▪ Infiltration Considerations: The native glacial till deposit that underlies the site possesses a relatively low permeability. Therefore, it does not appear feasible to infiltrate any significant amount of the on-site stormwater runoff. This summary should be used only in conjunction with the entire report for design purposes. It should be recognized that geotechnical details were not included or not fully developed in this section; as such, the report must be read in its entirety for a comprehensive understanding of the items presented above. Also, please refer to the GENERAL COMMENTS section for a discussion of the report limitations.