2621 ROCKEFELLER AVE Geotech Report 2022-10-25

t I Table 1. Elevation of Dense Glacial Deposits Approximate Ground Glacial Till Elevation Exploration Surface Elevation (feet) (feet) TP-1 116 112.5 1 - - - - — TP-2 115.5 111.5 TP-3 117 113 _-TP-4 110.5 107 _ 110.5 107 TP-6 110 _ , — 107 1 GROUNDWATER CONDITIONS We did not observe groundwater seepage in the test pit explorations. However, perched groundwater may be encountered within and overlying the denser glacial till during the wet season(October through May). - • CONCLUSIONS AND RECOMMENDATIONS EARTHQUAKE ENGINEERING 2003 IBC Seismic Design Information We recommend the 2003 International Building Code (IBC) parameters for Site Class, short period spectral response acceleration(SS), 1-second period spectral response acceleration (S1), and Seismic Coefficients FA and Fv presented in Table 2. Table 2. IBC Seismic Parameters 2003 IBC Parameter Recommended Value 1 Site Class C Short Period Spectral Response Acceleration,Ss(percent g) 117 II 1-Second Period Spectral Response Acceleration,Si(percent g) 41 Seismic Coefficient,FA 1.0 __ Seismic Coefficient,Fv 1.39 11 Liquefaction 11 Liquefaction refers to a condition where vibration or shaking of the ground, usually from earthquake forces,results in development of excess pore pressures in saturated soils and subsequent loss of strength in the deposit of soil so affected. In our opinion, the glacial soils at the site will not liquefy under the Idesign earthquake(magnitude 6.6 with a horizontal ground acceleration of 0.51 g). EARTHWORK IBased on the subsurface soil conditions encountered in the test pits,we expect that the soils at the site may be excavated using conventional heavy duty construction equipment. The materials we File No.12547-001-00 Page 3 GEOENGiNEERS February 3,2000