1725 GRAND AVE 2018-01-02 MF Import

r � � I November 10, 2000 G-1266 Gillette Residence Page 3 4.2 Uniform Buildieg Code Clasaification IAccording to the 1997 Unifortn Building Code(UBC), western Wuhington is claasified as I Seismic Zone 3 (Figure 16-2 in the UBC), which is assigned a Seismic Zone Factor, Z, of 0.30 � (Table 16-I in the UBC). The soil wnditions encounter� at the site during our investigation correspond best to a Soil Profile Type of S�and Soil Profile Description of Very Dense Soil , Profile(Table 16-J i�the UBC). Based on a Seismic Zone Factor(Z) of 0.3 and a Soil Pro61e Type of S�, the Seismic Coefficient C.is 0.33 (Table 16-Q in the UBC)and the Seismic I Coefficient C,,is 0.45 (Table 16-R in the UBC) for the site. 4.3 Liquefiction Aaaessment � � Liquefaction is a phenomenon where loose granular materials below the water table temporarily behave as a liquid due to strong shaking or vibrations, such as earthquakes. Clean, loose and saturated granular,naterials are the soil types susceptible to liquefaction phenoi7ena. It is our professional opinion the soils below the site are not susceptible to liquefaction. The soiis encountered below the site consisted of inedium dense to very dense sand. S.0 CONCLUSIONS AND RECOMMENDATIONS 5.1 General Based on the results of our study, it is our opinion that the house can be remodeled as planned, and the site is geotechnically suitable for the planned construction. The main geotechnical considerations for the proposed development include excavation for the proposed retaining wall, foundation support, underpinning of the existing foundations, and constniction of new basement slabs. Specific recommendations regarding the site development, including building foundation considerations, floor slabs, general site preparation and earthwork, structural 611 specifications, excavations and slopes, basement and retaining wall design parameters, and drainage considerations, are presented in the following sections. Geo Group Northwest, Inc. �, �L�