Y.S. KORANY* and R.G. DRYSDALE
Department of Civil Engineering, McMaster University
1280 Main St. W., Hamilton, Ontario, L8S 4L7 Canada
A large portion of the stock of existing older buildings in the world is constructed using unreinforced masonry walls (URM). Many of these buildings are of historic significance. Although URM buildings perform well under service gravity loads and low lateral loads, past and recent evidence of damage or collapse during earthquakes shows that they are vulnerable to the effects of inertia forces generated by earthquakes. Two types of failure are commonly observed for URM walls. These are in-plane failure characterized by a diagonal tensile crack pattern, and out-ofplane failure where cracks are primarily along the mortar bed joints. The out-of-plane excitement and failure of URM façades has been identified as the most significant hazard in a seismic event. New and modified techniques are required to economically enhance performance yet preserve the appearance of such buildings. This paper presents a new strengthening technique which utilizes epoxy impregnated carbon fibre rope mounted near the surface of the masonry walls, where reinforcement is most effective, using epoxy paste. The test results demonstrated the high efficiency of the proposed technique. Significant increases in cracking and ultimate capacities, deformability, and energy absorption were achieved for all reinforcing schemes compared to the original unreinforced behaviour.