Seismic resistance of unreinforced masonry cantilever walls in low seismicity areas

Abstract

The time-history analysis method, the response spectrum method and the equal energy method are considered in this paper to determine the seismic resistance of unreinforced masonry (URM) cantilever walls. Fundamental problems with each of the methods in predicting the response of a simple cantilever wall model to the El Centro earthquake have been identified. The response spectrum method underestimated the true seismic resistance of the wall by a factor of more than 2.0, whilst the equal energy method could overestimate the resistance of the wall by up to 3.5 times depending on the natural frequency adopted. Difficulties with establishing realistic dynamic properties of brickwalls are highlighted. A probabilistic procedure involving the analysis of a large number of representative ground motions and cantilever wall models is recommended for future investigations to derive reliable and simple expressions to predict the response of cantilever masonry walls.