Application of the push-over analysis to plan asymmetric building structures

For plan asymmetric building structures, the development of simplified non-linear methods based on push-over analysis requires a fundamental premise: the capability to predict the envelopes of the normalized lateral displacements. In this paper, an attempt has been made to verify an assumption which can be made to extend pushover analysis to plan irregular structures, i.e. conservativeness of the elastic prediction with respect to the envelope obtained with nonlinear dynamic analysis. To this end, idealized refined single-story models have been studied by non linear time-history analysis under bi-directional excitations. Some case studies and few selected results of extensive parametric studies are presented, indicating that elastic predictions are generally larger than the non-linear response. However, for some systems and combinations of the torsional parameters, it has been found that elastic predictions are not conservative and, therefore, further studies are needed to develop suitable procedures of pushover analysis for plan irregular structures.