By using the parameters determined in Table 12.2-1 and 11.5.1, the Reduced Design Spectral acceleration, Sa is determined automatically according to Section 12.9.1.2.

According to the structural system type, using the R, Cd and Ωo coefficients obtained from Table 12.2-1, R/Ie and the reduced design spectral acceleration are calculated automatically.


Symbols

Cd = Deflection amplification factor
Ie= Seismic importance factor
R = Response modification coefficient


The reduced design spectral acceleration Sa, which is the ordinate of the reduced design acceleration spectrum for a given natural vibration period T, used to determine the reduced seismic loads in the horizontal direction, is that of Sa Design Response Spectrum., is obtained by dividing the R, Reduced Design Acceleration Spectrum for Modal Analysis and multiply with Ie.

On the Analysis ASCE 7-16 Wizard - Design Spectra tab, the spectral acceleration coefficients obtained from USGB based on the coordinates and the horizontal elastic design spectrum Sa is calculated according to the formula below . Design Response Spectrum., it is represented by a total of 4 functions, different in each region, and shown with the graph below.