9421950 Ehsani Recent earthquakes have demonstrated the life safety hazard posed by unreinforced masonry (URM) wall structures. It is proposed to strengthen the URM walls by fiber composites. The flexibility, light weight and high tensile strength of composites makes them an ideal material for strengthening masonry structures. A recent study has demonstrated that significant increases in strength and ductility could be achieved for static loading. The primary objective of this research project will be to study the out-of-plane cyclic behavior of unreinforced masonry (URM) walls strengthened with fiber composites and to develop analysis and design procedures or seismic strengthening of existing URM structures. Six wall specimens, each approximately 8 ft wide and 10 ft tall, will be tested. Two different height to thickness ratios (h/t = 14 and 28) constructed of one or two wythes of bricks will be examined. Composite fabrics epoxied to the wall will either fully cover both faces of the wall, or will be applied as vertical strips spaced apart and staggered on the opposite faces of the wall. Test results will be used to develop design guidelines for retrofitting of URM structures. The proposed research will be closely coordinated with a parallel research investigating the in-plane cyclic behavior of fiber reinforced URM wall at the University of Michigan. ***
