Evaluation of a multimode pushover procedure for asymmetric in plan buildings under biaxial seismic excitation

Abstract

In this paper a recently developed multimode pushover procedure for the approximate estimation of structural performance of asymmetric in plan buildings under biaxial seismic excitation is evaluated. Its main idea is that the seismic response of an asymmetric multi-degree-of-freedom system with $$N$$ degrees of freedom under biaxial excitation can be related to the responses of $$N$$ ‘modal’ equivalent single-degree-of-freedom (E-SDOF) systems under uniaxial excitation. The steps of the proposed methodology are quite similar to those of the well-known modal pushover analysis. However, the establishment of the (E-SDOF) systems is based on a new concept, in order to take into account multidirectional seismic effects. The proposed methodology does not require independent analysis in the two orthogonal directions and therefore the application of simplified superposition rules for the combination of seismic component effects is avoided. After a brief outline of the theoretical background and the application process, an extensive evaluation study is presented, which shows that, in general, the proposed methodology provides a reasonable estimation for the vast majority of the calculated response parameters.