Seismic reduction for modal analysis is determined automatically by R/Ie according to

R and Ie 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.


R = The response modification factor in Table 12.2-1
Ie = The Importance Factor

The design response spectrum is simulated of linear elastic structures. Division of the spectral ordinates by the response modification coefficient, R, accounts for inelastic behavior, and multiplication of spectral ordinates by the Importance Factor, Ie, provides the additional strength needed to improve the performance of important structures according to C12.9.1.2.