LAUSR

Abstract Appropriate selection of strengthening methods for existing historic masonry structures is of utmost importance to improve the seismic behavior without altering their aesthetics. The present research was aimed to study the in-situ strengthening methods applicable to seismic strengthening for historic masonry buildings. The strengthening methods include embedment of polymer mortar, steel strips bonded by polymer mortar and a combination of both into bed joints. To assess the effectiveness of the strengthening methods, a detailed experimental investigation on one un-strengthened and four strengthened masonry walls were carried out under cyclic lateral loads. The effectiveness of strengthening methods was evaluated by comparing failure modes and seismic performance, in terms of strength, deformation capacity, stiffness degradation, energy dissipation and equivalent viscous damping. It was found that presence of high strength polymer mortar improved the deformation behavior of masonry walls, whereas, the specimens strengthened with steel strips significantly enhanced the strength, deformation and energy dissipation capacity. The adopted strengthening methods showed insignificant influence on the initial stiffness of the masonry walls. Based on the observed damage and failure, empirical expressions were established to predict the in-plane shear capacity of the strengthened masonry walls and were verified with the previous experimental results.