Seismic Behavior of Unreinforced and Confined Brick Masonry Walls Before and After Ferrocement Overlay Retrofitting

Abstract

This study presents experimental results of quasi-static load test conducted on two full-scale brick masonry walls, one unreinforced and the other confined, to investigate their in-plane lateral load behavior before and after retrofitting. The walls were constructed closely following the masonry system commonly used in Pakistan and in most South Asian countries. The walls before retrofitting were tested to their peak resistance. The damaged walls were then retrofitted with grout injection followed by ferrocement overlay and retested to their ultimate failure under the identical conditions. The effectiveness of the proposed confinement and retrofitting scheme was assessed from the damage pattern, energy dissipation, and force-deformation behavior of the walls tested before and after retrofitting. The test results before retrofitting show that the capacity of confined masonry wall is almost double to that of unreinforced masonry wall. The test results after retrofitting indicate that the applied retrofitting scheme significantly enhanced the lateral load capacity of the unreinforced masonry wall, however it was marginally beneficial in the confined masonry walls. The test results are also compared with American Society of Civil Engineers (ASCE) standards in terms of stiffness, strength and acceptable deformations. It is concluded that the guidelines provide reasonable estimates of the test observations.