Behavior of unreinforced masonry walls (URM) strengthened with FRP composite materials

Several traditional techniques have been used to increase the strength, stiffness and ductility of UMW. Most of the methods prove effectiveness but they add considerable mass and thickness to the original structure, affect the aesthetics, and are labor intensive. A better and a more effective way to repair/strengthen the UMW is through using fiber reinforced polymer (FRP) composite laminates. Epoxy bonding a thin laminate of composite materials to the exterior surfaces of these walls will force the individual brick elements to act as an integrated system. This paper presents the results of the work carded out to investigate the capability of glass FRP (GFRP) laminates in strengthening the masonry walls when subjected to out-of-plane and in-plane flexural and shear stresses. Six masonry walls were tested after the composite retrofit. Two of the walls (flexure specimens) were loaded with out-of-plane bending, and four of the walls were subjected to in-plane loading (two for shear and other two for flexure) . A significant strength increase was observed for all strengthened shear and bending specimens. Failure occurred for most of the cases due to either compression failure of bricks or due to wall damage in the anchor area especially for shear specimens