2106 GRAND AVE 2016-01-01 MF Import

� GEOTEQIWCAL HJGINEERING STUDY E•12863 Mar[h 17,2007 � Seismic Design Considerations � Earthquakes occur in the Puget Lowland with regularity; however, the majority of these events are of such low magnitude they are not detected without instruments. Large � earthquakes do occur, as indicated by the 1949, 7.2 magnitude earthquake in the Olympia area and the 1965, 6.5 magnitude earthquake in the Midway area and the 2001, 6.8 1 magnitude earthquake in the Nisqually area. There are three potential geologic hazards associated with a strong motion seismic event at � this site: ground rupture, liquefaction, and ground motion response. Ground Rupture IThe strongest eartha�3kes in the Puget Lowland are widespread, subcrustal events, ranging in depth from 30 to 55 miles. Surface faulting from these deep events has not been � documented to date. Therefore, it is our opinion, that the risk of ground rupture at this site during a strong motion seismic event is negligible. ( Liquefaction Liquefaction is a phenomenon in which soils lose all shear strength for short periods of time I during an earthquake. Groundshaking of su�cient duration results in the loss of grain-to- grain contact and rapid increase in pore water pressure, causing the soil to behave as a fluid. To have a potential for liquefaction, a soil must be cohesionless with a grain-size distribution i of a specified range (generally sand and silt), it must be loose, it must be below the i groundwater table, and it must be subject to sufficient magnitude and duration of groundshaking. The effects of liquefaction may be large total and/or differential settlement for i siructures founded in the liquefying soils. I In our opinion, the liquefaction potential at tl�is site is low. This conciusion is based on the ' dense soils encountered at the boring locations and the lack of a shallow groundwater table. ' Ground Motion Response 1 � The 2003 Intemational8uilding Code (IBC) regulations contain a static force procedure and a dynamic force procedure for design-base shear calculations. Based on the encountered soil conditions, it is our opinion Site Class C, "Very dense soil and soft rock," as defined in Table 1615.1.1 of the IBC, shouid be used to characterize the site soils. In accordance with Section 1615.1.2 of the IBC, Seismic Values SmS = 1.36 and Sm, = 0.56 should be used for design. i I EARTIi CONSUI.TiNG INCOFtPORATED Page 10