Investigation of the Influences of Asymmetric Damages on Seismic Assessments for Existing Masonry Structures

Abstract

Masonry structures have been widely used in residences and in commercial and public buildings around the world. Most existing masonry structures have asymmetric damages that significantly influence their safety in earthquakes. Their seismic assessment would not be reliable without considering the influences of these asymmetric damages. To address the issue, the authors conduct a pseudo-static test on a masonry model with asymmetric damages. Before the test, the authors apply asymmetric damages by weakening one of the load-bearing walls of the model. In the test, the authors apply synchronized horizontal displacements on top of the load-bearing walls in a cyclical manner, and record the deformation, crack distributions, and reaction forces. Based on the records, the authors analyze the deformation patterns, failure procedure, cracking pattern, hysteretic behaviors, and stiffness degradation of the model. The test results indicate that asymmetric damages cause nontrivial structural rotation under horizontal loading, and then make the walls fail in different patterns. The structural rotation significantly influences the distribution of the seismic internal forces. Excluding the rotation in the calculation, one can underestimate the seismic internal forces for walls without damages and overestimate the forces for walls with damages. The structural rotation also influences the seismic strengthening scheme. One should apply strengthening measures both in the member scale and in the structural scale. The findings can be referred to in seismic assessment for most existing masonry structures.