The IBC Design Response Spectrum correlate time period T and Spectral Acceleration, defining three zones. Two critical zones are:
T < TS governs low-rise structures of short periods
T > TS governs tall structures of long periods
where
T = time period of structure (T ~ 0.1 sec. per story - or per ASCE 7 table 1615.1.1)
TS = SDS/SD1 (See the following graphs for SDS and SD1)
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T < TS governs low-rise structures of short periods
T > TS governs tall structures of long periods
where
T = time period of structure (T ~ 0.1 sec. per story - or per ASCE 7 table 1615.1.1)
TS = SDS/SD1 (See the following graphs for SDS and SD1)
