P11.01: A multi‐mode pushover analysis procedure to estimate seismic demands for steel moment‐resisting frames

Abstract

ABSTRACTThe main objective of the paper is the development and evaluation of a multi‐mode pushover procedure for the approximate analysis of the seismic response of steel moment‐resisting frames. A generalized force vector derived from modal combination simulates the instantaneous force distribution acting on the structure when the interstorey drift reaches its maximum value during the dynamic response to a seismic excitation. A set of generalized force vectors (each associated to maximum drift at one story) is applied separately to the structure until the corresponding target interstorey drift is attained. The envelope of results gives the maximum value of each response parameter. The proposed pushover procedure allows a simple implementation, reducing the computational effort compared with adaptive nonlinear static procedures and nonlinear response history analysis. Moreover, it does not suffer from the statistical combination of inelastic modal responses calculated separately. Its effectiveness and accuracy are verified through a comparative study involving regular steel moment resisting frames subjected to acceleration records.