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January 3, 2025 <br />HWA Project No. 2021-159-21 <br />Geotechnical Engineering Report 15 HWA GEOSCIENCES INC. <br />Port Gardner Storage Facility <br />3) Structures on Site Class E sites with S1 greater than or equal to 0.2, provided that T is <br />less than or equal to Ts and the equivalent static force procedure is used for design. <br />The proposed structures are anticipated to have a fundamental period less than ½ second and as <br />such the use of Site Class “E” parameters would be appropriate. However, unless a site-specific <br />ground motions hazard analysis is performed, the requirements in exception 1 and 3 (from ASCE <br />7-16) listed above will need to be followed. <br />The associated probabilistic ground acceleration values and site coefficients for the general site <br />area were obtained from the Applied Technology Council (2024) Seismic Hazard Maps. The <br />risk-targeted seismic values and coefficient are presented in Table 1. Should the information <br />used as a basis for this design be incorrect, HWA should be notified to provide appropriate <br />recommendations. <br />Based on Tables 1613.2.5(1) and 1613.2.5(2) of IBC (2021), the Seismic Design Category for <br />the site is “D.” <br />Table 1. Seismic Design Parameters, Site Class E* <br /> <br />Period <br />(sec) <br />Mapped <br />MCE <br />Spectral <br />Response <br />Acceleration <br />(g) <br />Site <br />Coefficients <br />Adjusted <br />MCE Spectral <br />Response <br />Acceleration <br />(g) <br />Design <br />Spectral <br />Response <br />Acceleration <br />(g) <br /> <br />Transition <br />Point <br />Period <br />(sec) <br /> 0.0 PGA 0.532 FPG <br />A 1.100 PGAM 0.585 - - T0 0.132 <br /> 0.2 Ss 1.239 Fa 1.004 SMs 1.244 SDs 0.830 Ts 0.658 <br /> 1.0 S1 0.440 Fv 1.860 SM1 0.818 SD1 0.546 TL 6 <br />Notes: <br />*2% Probability of Exceedance in 50 years for Latitude 47.9885° N and Longitude -122.2154° E <br />PGA = Peak ground acceleration <br />FPGA = PGA site coefficient <br />PGAM = Maximum considered earthquake geometric mean peak ground acceleration adjusted for Site Class <br />effects <br />SS = Short period (0.2 second) Mapped Spectral Acceleration <br />S1 = 1.0 second period Mapped Spectral Acceleration <br />SMS = Spectral Response adjusted for site class effects for short period = Fa • SS <br />SM1 = Spectral Response adjusted for site class effects for 1-second period = Fv • S1 <br />SDS = Design Spectral Response Acceleration for short period = 2/3 • SMS