In-plane shear behavior of masonry walls strengthened with HDC repointing in bed joints and HDC layer under diagonal compression loads

In this study, a simple and easy construction strengthening method, referred to as high ductile concrete (HDC) repointing in bed joints and/or HDC overlay, were proposed for improving in-plane shear behavior of unreinforced masonry (URM) walls. For this purpose, one URM wall and five HDC-strengthened masonry walls were prepared and tested under diagonal compression. The failure mode, shear stress-strain behavior, shear strength and ultimate strain were analyzed and discussed. HDC strengthening system improved the shear failure mode of masonry walls, preventing masonry from serious damage. The reinforced masonry walls exhibited a more ductile failure and kept good integrality. Besides, HDC system effectively increased both shear strength and ultimate shear strain of masonry walls, with normalized value ranging from 1.8 to 6.5 for shear strength and from 21.1 to 109.0 for ultimate strain. Based on the contribution provided by HDC repointing and HDC layer, the results obtained from the current paper allowed the use of superposition method to calculate shear capacity of HDC-strengthened masonry walls. The analytical model gave a conservative and reliable prediction, which can be used in engineering design.