3003 W CASINO RD BLDG 40-58 Geotech Report 2022-10-25

t stabilization should be seeded with an appropriate grass seed mixture,or hydroseeded with an appropriate seed-mulch-fertilizer mixture. 3.6 SEISMIC DESIGN CONSIDERATIONS The Pacific Northwest is seismically active and the project site will be subjected to ground shaking during a moderate to major earthquake. Consequently, moderate to large levels of earthquake shaking should be anticipated during the design life of the project,and Building 40-27 should be designed to resist earthquake loading using appropriate design methodology. We understand seismic design of Building 40-27 will be in accordance with the 2012 International Building Code (IBC). According to Chapter 20 of ASCE 7,the site classifies as Site Class D(stiff soil). This classification is based upon the relatively thick layer of fill present in many portions of the building footprint. The following spectral accelerations for a 2 percent probability of exceedance in 50 years (1-in-2,475-year return period) should be used to determine the design response spectrum [from the U.S. Geological Survey(USGS)U.S. Seismic Design Maps application(USGS website 2014)]: Spectral Acceleration for short periods(Ss): 144.7%of gravity(1.447g) Spectral Acceleration for a 1-second period(Si): 55.8%of gravity(0.558g) The above values can be modified for Site Class D using 1.000 for site coefficient Fa, and 1.500 for site coefficient Fv. The design spectral response acceleration parameters can be taken as two-thirds of the maximum considered earthquake spectral response acceleration presented above. Using the above site class and design adjustments,the following design spectral acceleration parameters can be used: Sips =0.965 SDI= 0.558. Soil liquefaction is a phenomenon generally limited to granular soils located below the water table that are in a relatively loose, unconsolidated condition at the time of a large, nearby earthquake. Occasional loose, saturated zones were encountered at depth in a few of the exploratory borings. However, these zones appear to be discontinuous, relatively deep, and limited in thickness and lateral extent; they do not present a liquefaction problem that should be considered to impact the design of building foundations or slabs. The dense, glacially consolidated deposits that underlie the project site are anticipated to have a low susceptibility to soil liquefaction. Consequently,it is our opinion that no special liquefaction-related design or construction procedures will be necessary for this project. 5/16/14 P.\1423\002\010\FileRm\R\Draft Bldg 40-58 Report\Bldg 40-58_draft rpt.docx INTERIM D RA F T 3-5