Enhancing shear performance of masonry wallettes with high ductile fiber-reinforced concrete

Unreinforced concrete block masonry (URM) walls are seismically vulnerable due to the limited in-plane shear strength for resisting the earthquake action, typically showing the diagonal brittle shear failure and collapse, imperiling human lives. Therefore, to improve the diagonal shear performance of URM walls, this paper presents an investigation of the mechanical properties concerning the URM wallettes retrofitted using various strengthening configurations of the high ductile fiber-reinforced concrete overlay, subject to the monotonic diagonal compression tests. The test results indicated that the retrofitting techniques could mitigate the brittle shear behavior and improve the shear strength of the URM wallettes. However, for the double-sided surface layer retrofitted specimens, the bearing capacity and stiffness increase while the deformation capacity decreases to a certain extent. Based on the failure mode of each test specimen, the calculation formulas were proposed to predict the load-bearing capacity for each wallette, and the calculated results matched approximately with the test results, which is informative for the in-plane diagonal shear engineering design of the high ductile fiber-reinforced concrete-based retrofitted concrete block masonry walls.