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Empirical Period

Approximate fundamental period Ta = Ct · hn^x per NSCP 2015 §208.5.2.2 / ASCE 7 §12.8.2.1, plus an upper-limit T_max = Cu · Ta for code minimum base shear.

Input

Results

Ct
Exponent x
Approx. period Ta
Cu (period coef.)
T_max = Cu · Ta
Use for design (≤ T_max)
Method

Method A: Ta = Ct · hn^x (hn in meters; coefficients shown). Cu (ASCE 7 Table 12.8-1 / NSCP 208.5.2.2): SD1 ≥ 0.40 → 1.4; 0.30 → 1.4; 0.20 → 1.5; 0.15 → 1.6; ≤ 0.10 → 1.7. For analysis-derived T from rational analysis, used T but not greater than Cu · Ta for base-shear computation.