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C CORNERSTONE EARTH GROUP building areas. Where minimal side yards are planned (10 feet or less), we recommend that area drains collect surface runoff and transmit the runoff to other suitable landscape drainage facilities to prevent ponding adjacent to building foundations. Landscape drainage such as drain inlets and storm water filtration and/or infiltration trenches should be provided to collect and transmit storm water runoff to project storm drains, andfor detention or retention facilities. Although the PT-mat foundations are designed to accommodate some moisture variability within the near-surface soils, excessive moisture or desiccation may result in additional differential foundation movement. SECTION 7: FOUNDATIONS 7.1 SEISMIC DESIGN CRITERIA We assume that the project structural design will be based on the 2007 California Building Code (CBC), which is based on the 2006 International Building Code (IBC). The 2007 CBC provides criteria for the seismic design of buildings in Chapter 16. The "Seismic Coefficients" used to design buildings are established based on a series of tables and figures addressing different site factors, including the soil profile in the upper 100 feet below grade and mapped spectral acceleration parameters based on distance to the controlling seismic source/fault system. Based on our borings and review of local geologic maps, the site is underlain by stiff or dense alluvial soils to depths on the order of 100 feet with SPT "N" values between 15 and 50 blows per foot; therefore, we have classified the site as Soil Classification D. The mapped spectral acceleration parameters Ss and Si were calculated using the USGS computer program Earthquake Ground Motion Parameters, Version 5.0.8, revision date November 20, 2007, based on the site coordinates presented below and the site classification. The table below lists the various factors used to determine the seismic coefficients. Table 5: 2007 CBC Site Classification and Seismic Coefficients Classification/Coefficient Design Value Soil Classification (Table 1613A.5.2) D Site Latitude 37.680151° Site Longitude -121.858526° Short Period Mapped Spectral Acceleration, Ss' 1.5g 1-second Period Mapped Spectral Acceleration, St' 0.6g Seismic Coefficient Fe (Table 1613A.5.3(1)) 1.0 Seismic Coefficient F" (Table 1613A.5.3(2)) 1.5 'Spectral accelerations based on 2007 CBC Figures 1613.5(3) and 1613.5(4) as interpreted by the program Earthquake Ground Motion Parameters, Version 5.0.8 (USGS). Ponderosa Active Adult Community Page 17 132-2-1