Abstract：High ductile concrete (HDC) was used to improve the seismic behavior of unreinforced brick masonry walls. 4 HDC-retrofitted walls and 2 unretrofitted masonry walls served as reference specimens were tested subject to low-cycle repeated loading. The influences of different strengthening schemes (strips and coatings) and mortar strengths on the failure patterns, the hysteretic characteristics, the lateral strength, the stiffness degradation, etc. were investigated. Test results show that retrofitting masonry walls with HDC can effectively improve the lateral strength and the displacement ductility, delay the occurrence of cracks and the degradation of the stiffness, and reduce the brittle characteristic of failure modes; HDC strips can change the failure mode and provide an effective restraint for the masonry wall. Based on the failure pattern of specimens, calculation methods were proposed to estimate the ultimate lateral strengths of retrofitted masonry walls, and then, the methods were validated based on the test results.
