Practical implementation of generalized pushover analysis for multimodal pushover analysis

Alıcı, Fırat Soner
Sucuoğlu, Haluk
A generalized pushover analysis procedure was previously developed for estimating the inelastic seismic response of structures under earthquake ground excitations. The procedure consists of applying different generalized force vectors separately for each story to the structure in an incremental form with increasing amplitude, until an estimated target interstory drift demand is obtained. A generalized force vector is expressed as a combination of modal forces, and simulates the instantaneous force distribution acting on the system when the interstory drift at a given story reaches its maximum value during dynamic response to a seismic excitation. Each nonlinear static analysis under a generalized force vector activates all modes of a multi degree of freedom system, simultaneously. Correspondingly, inelastic actions develop in members with the contribution of all instantaneous modes in the nonlinear response range. A practical implementation of the proposed generalized pushover analysis is presented in this study. The method is applied to a 12 story frame and a 20 story frame-wall system, and the results are obtained under six spectrum-compatible ground motions. First, it has been demonstrated that generalized pushover analysis is successful in estimating maximum member deformations and exact in determining member forces under a ground excitation with reference to nonlinear response history analysis. Then, it is shown that the results obtained from generalized pushover analysis by using the mean spectrum of six ground motions are almost identical to the mean of the results obtained from separate generalized pushover analyses under six ground motions. Moreover, these mean results are very close to the mean of the results obtained from six nonlinear response history analyses.
Citation Formats
F. S. Alıcı and H. Sucuoğlu, “Practical implementation of generalized pushover analysis for multimodal pushover analysis,” 2015, Accessed: 00, 2021. [Online]. Available: