Is Modal Pushover Analysis accurate in estimating seismic demands for unreinforced masonry buildings with flexible diaphragms?

Abstract

Accurate estimation of the inelastic response demands of buildings subjected to a specific in-tensity of ground excitation is an essential component of a performance-based seismic assessment. In recent decades, the application of the nonlinear static (pushover) analysis method has become an accepted practice in estimating the peak seismic demands of many structural systems. For unreinforced masonry (URM) build-ings, the commonly utilized pushover analysis methods assume the building to respond in a single-mode. However, many URM buildings contain flexible timber floor and roof diaphragms, and the responses of such buildings are known to be governed by multiple dominant modes. Recognizing the limitation of the single-mode assumption in analyzing URM buildings with flexible diaphragms, several researchers have nominated the Modal Pushover Analysis (MPA) as a suitable alternative analysis method. The present paper investigates the applicability of the MPA in predicting the peak seismic responses of URM buildings with flexible dia-phragms, and identifies the limitation of the method in capturing the cumulative nature of shear damage.