Numerical Seismic Response and Failure Modes of Old URM Walls Under Lateral Loading

Abstract

Most of existing constructions were built of unreinforced masonry. The performance of this material is different from the masonry units and mortar joints. This behavior is governed by the physical and mechanical characteristics of the composite, self-weight, transmitted vertical loading and earthquake shaking. The heterogeneity of masonry is also reflected in the anisotropic behavior of this material, which presents different performance and failure modes when subjected to lateral seismic forces. The main objective of the present paper is the simulation of typical failure mechanisms of compact URM walls without transmitted vertical loading, only taking into account their self-weight. The numerical behavior and failure mechanisms at the masonry walls (with solid section and perforated) was captured by the used material model and the pushover method. The obtained failure modes by bed-joint sliding at the solid section wall and stepped shear cracks at the wall with window are similar to the observed in post-earthquake investigations on URM walls with light cover reported in literature. The low tensile strength of masonry and the lack of vertical loading on the studied unreinforced masonry walls induced different failure mechanisms and behavior. In brief, the identification of in-plane performance and collapse is difficult to predict and strongly depends on the physical and mechanical properties of masonry, vertical loading and seismic forces.