The seismic response coefficient Cs is determined automatically by Equation 12.8-2, 12.8-3, 12.8-4, 12.8-5 and 12.8-6.
R, Ie and TL coefficients in the equations are defined by user.
R and Ie coefficients are selected by the user in the analysis settings wizard and report results are checked automatically.
Cs = The seismic response coefficient
SD1 = The design spectral response acceleration parameter at a period of 1.0 s,
SDS = The design spectral response acceleration parameter in the short period range
R = The response modification factor in Table 12.2-1
Ie = The Importance Factor
T = The fundamental period of the structure (s)
TL = Long-period transition period (s)
S1 = The mapped maximum considered earthquake spectral response acceleration parameter
126.96.36.199 Calculation of Seismic Response Coefficient
The seismic response coefficient, Cs, is determined in accordance with Eq. (12.8-2).
The value of Cs computed in accordance with Eq. (12.8-2) need not exceed eq 12.8-3 and/or 12.8-4
Cs should not be less than
In addition, for structures located where S1 is equal to or greater than 0.6g, Cs should not be less than