Seismic Performance of Masonry Walls Strengthened with Externally Attached Precast Concrete Panels under Cyclic Loading

Abstract

This study aims to develop a low-disruption prefabricated strengthening method to improve the seismic performance of existing masonry walls by externally attaching precast concrete panels. Four masonry wall specimens are tested under quasi-static cyclic loading, including one unstrengthened control wall and three strengthened walls with grouting, shear-key, and combined grouting and shear-key connections. Failure mode, crack development, hysteretic response, energy dissipation, displacement ductility, bearing capacity, and lateral stiffness are evaluated. Results show that the strengthened specimens increase ultimate bearing capacity by 5.92, 5.70, and 5.46 times, respectively, relative to the control specimen, and lateral stiffness by 2.76, 1.94, and 2.30 times, respectively, compared with the control specimen. Grouting improves capacity and stiffness, while shear keys enhance ductility but induce severe local damage. The combined connection provides better deformation compatibility, crack control, and a more balanced seismic performance.