4937 EVERGREEN WAY QFC FUELING STATION Geotech Report 2023-02-17

V Geotechnical Engineering Report 3 January 7,2020 QFC 852 Fuel Station,Everett, Washington RGI Project No.2019-258A variations in the amount of rainfall, runoff, and other factors not evident at the time the explorations were performed. In addition, perched water can develop within seams and layers contained in fill soils or higher permeability soils overlying less permeable soils following periods of heavy or prolonged precipitation. 4.5 SEISMIC CONSIDERATIONS Based on the 2015 International Building Code (IBC), RGI recommends the follow seismic parameters in Table 1 be used for design. Table 1 IBC Seismic Parameters 2015 IBC Parameter Value Site Soil Class' DZ Site Latitude 47.952457° N Site Longitude 122.21214°W Maximum considered earthquake spectral response acceleration parameters (g) Ss=1.371, S1 =0.521 Spectral response acceleration parameters adjusted for site Sms =1.371, Smt =0.781 class (g) Design spectral response acceleration parameters (g) Sds =0.914, Sd1 =0.521 1 Note: In general accordance with the USGS 2015 International Building Code. IBC Site Class is based on the average characteristics of the upper 100 feet of the subsurface profile. 2 Note:The 2015 International Building Code requires a site soil profile determination extending to a depth of 100 feet for seismic site classification. The current scope of our services does not include the required 100 foot soil profile determination. Borings extended to a maximum depth of 31.5 feet, and this seismic site class definition considers that similar soil continues below the maximum depth of the subsurface exploration. Liquefaction is a phenomenon where there is a reduction or complete loss of soil strength due to an increase in water pressure induced by vibrations from a seismic event. Liquefaction mainly affects geologically recent deposits of fine-grained sands that are below the groundwater table. Soils of this nature derive their strength from intergranular friction. The generated water pressure or pore pressure essentially separates the soil rains and eliminates this inter ranular friction thus reducin or eliminatin the soil s g g g g strength. RGI reviewed the soil conditions encountered during field exploration and assessed the potential for liquefaction of the site's soil during an earthquake. Due to the dense nature of the deposits and depth of ground water level, RGI considers the potential for liquefaction of the site soils to be minimal. i- RILEYGROUP