Design Spectral Response Accelerations SDS / SD1 (ASCE 7-22 11.4)
Site-adjust the mapped MCER accelerations (SMS = Fa Ss, SM1 = Fv S1) then take two-thirds for design (SDS = 2/3 SMS, SD1 = 2/3 SM1). Ss 1.0, S1 0.4, Site Class D (Fa 1.1, Fv 1.6) -> SDS 0.733g, SD1 0.427g, the exact inputs seismic-base-shear consumes. A design aid; the engineer of record governs.
Formula and source
SMS = Fa Ss; SM1 = Fv S1; SDS = (2/3) SMS; SD1 = (2/3) SM1.
The ASCE 7-22 11.4 site-adjusted MCER and design spectral response accelerations, by name.
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