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Design Maps Detailed Report <br />Page 1 of 6 <br />USGS Design Maps Detailed Report <br />ASCE 7-10 Standard (33.77551°N, 117.86965°W) <br />Site Class D - "Stiff Soil", Risk Category I/II/III <br />Section 11.4.1 — Mapped Acceleration Parameters <br />Note: Ground motion values provided below are for the direction of maximum horizontal <br />spectral response acceleration. They have been converted from corresponding geometric <br />mean ground motions computed by the USGS by applying factors of 1.1 (to obtain Ss) and <br />1.3 (to obtain Si). Maps in the 2010 ASCE-7 Standard are provided for Site Class B. <br />Adjustments for other Site Classes are made, as needed, in Section 11.4.3. <br />From Figure 22-1 ' <br />Ss = 1.478 g <br />From Figure 22-2 « <br />S, = 0.540 g <br />Section 11.4.2 — Site Class <br />The authority having jurisdiction (not <br />the USGS), site -specific geotechnical data, and/or <br />the default has classified the site as <br />Site Class D, based on the site soil properties in <br />accordance with Chapter 20. <br />Table <br />20.3-1 Site Classification <br />Site Class <br />vs N or Na, su <br />A. Hard Rock <br />>5,000 ft/s N/A N/A <br />B. Rock <br />2,500 to 5,000 ft/s N/A N/A <br />C. Very dense soil and soft rock <br />1,200 to 2,500 ft/s >50 >2,000 psf <br />D. Stiff Soil <br />600 to 1,200 ft/s 15 to 50 1,000 to 2,000 psf <br />E. Soft clay soil <br /><600 ft/s <15 <1,000 psf <br />Any profile with more than 10 ft of soil having the characteristics: <br />• Plasticity index PI > 20, <br />• Moisture content w >- 40%, and <br />• Undrained shear strength s. < 500 psf <br />F. Soils requiring site response <br />See Section 20.3.1 <br />analysis in accordance with Section <br />21.1 <br />For SI: 1ft/s = 0.3048 m/s 1lb/ft2 = 0.0479 kN/m2 <br />https:Hprod01-earthquake. cr. usgs. gov/desig nma ps/us/re po rt. php?template=minimal&latitude=33.775505&I... 10/25/2018 <br />