Strengthening with FRP bars of URM walls subject to out-of-plane loads

This paper presents the results of an experimental program on the flexural behavior of un-reinforced masonry (URM) walls strengthened with near surface mounted (NSM) fiber reinforced polymers (FRP) bars. A total of 15 URM walls reinforced with NSM FRP bars were tested. The specimens were strengthened with different amounts of reinforcement to observe their improved performance and the mode of failure. The influence of the bar shape (i.e., circular vs. rectangular), FRP material, dimension of the groove and type of embedding material (i.e., epoxy or cementitious-based paste), were studied. Based on experimental evidence and on the data found in the literature, the paper provides criteria that can be used in the development of design guidelines.