Contribution of Externally Bonded FRP to Flexural Capacity of Reinforced Masonry Walls Subjected to Out-Of-Plane Load

Masonry walls have failed out of plane much more frequently than they have in plane; however, more research and investigations have aimed to improving in plane capacity. The objective of this study is to investigate the out-of-plane flexural performance of reinforced masonry walls and evaluate the contribution of externally bonded fiber-reinforced polymer (FRP) sheets and strips to flexural capacity. Nine fully grouted reinforced masonry walls were built using concrete masonry units and type S mortar. The out-of-plane loading was simulated by four-point bending with an effective span of 1.12 m (44 in.) between the supports. The reinforced walls subjected to cyclic load at a rate 1.27 mm/min. (0.05in./min). The reference masonry wall was in running bond pattern and reinforced with 2 No. 4 steel bars. The following experimental parameters were investigated: the type and amount of FRP composite, steel reinforcement ratio, and the effect of surface preparation. The test setup, instrumentation of the specimens and the discussion for the results and modes of failure are described in this study. The general behavior of the reference and strengthened specimens are characterized by load–deflection curve responses. Different modes of failure, including compressive concrete crushing failure, FRP rupture, and FRP reinforcement debonding from the masonry substrate occurred in the strengthened reinforced walls