Practical Nonlinear Analysis Methods for Flexure-Dominated Reinforced Masonry Shear Walls

Abstract

Reinforced masonry (RM) shear walls are the main seismic force–resisting elements in masonry buildings. Current guidelines and nonlinear modeling methods for evaluating the seismic performance of existing RM shear walls were developed many years ago based on limited experimental data. They tend to underestimate the displacement capacity of RM walls by a significant amount. This paper presents a modeling method along with suitable material models, based on a fiber-section beam-column element idealization, to capture the nonlinear in-plane cyclic behavior of flexure-dominated RM walls. The modeling method accounts for the buckling and low-cycle fatigue of vertical reinforcing bars, which often occur in the toe regions of RM walls under severe seismic actions, in an approximate manner. The model has been validated by experimental data on fully grouted planar walls and T-walls constructed of concrete masonry units. Moreover, a simple and rational method to construct lateral force-versus-lateral displacement backbone curves for flexure-dominated RM walls is presented. The proposed method produces backbone curves that show a significantly better agreement with experimental data compared with that recommended in current guidelines.