Fiber Reinforced Polymer (FRP) laminates have been successfully used for the strengthening of masonry panels subject to out-of-plane loads. An alternative to this technique is the use near surface mounted (NSM) FRP bars. This technique consists of placing a bar in a groove cut into the surface of the member being strengthened. The FRP bar may be embedded in an epoxy- or cementitious-based paste, which transfers stresses between the substrate and the bar. The successful use of NSM FRP bars in the strengthening of concrete members has been extended to unreinforced masonry (URM) walls, one of the building components most prone to failure during a seismic event. This paper presents the results of an experimental program on the flexural behavior of URM walls strengthened with (NSM) FRP bars and FRP laminates. URM walls reinforced with NSM FRP bars and FRP laminates 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), dimension of the groove and type of embedding material (i.e. epoxy or cementitious-based paste), were studied. Two types of FRP fabrics, glass (GFRP) and carbon (CFRP), were used as externally bonded reinforcement to provide the benchmark. Strength and pseudo-ductility of URM walls were significantly increased by strengthening with FRP bars and laminates. Based on experimental evidence, the paper presents an extensive comparison between the mechanical response of the two reinforcement systems.
Comparison between FRP strengthening techniques on the out-of-plane behaviour of URM masonry walls
GALATI, Nestore;MICELLI, Francesco;LA TEGOLA, Antonio;
2004-01-01
Abstract
Fiber Reinforced Polymer (FRP) laminates have been successfully used for the strengthening of masonry panels subject to out-of-plane loads. An alternative to this technique is the use near surface mounted (NSM) FRP bars. This technique consists of placing a bar in a groove cut into the surface of the member being strengthened. The FRP bar may be embedded in an epoxy- or cementitious-based paste, which transfers stresses between the substrate and the bar. The successful use of NSM FRP bars in the strengthening of concrete members has been extended to unreinforced masonry (URM) walls, one of the building components most prone to failure during a seismic event. This paper presents the results of an experimental program on the flexural behavior of URM walls strengthened with (NSM) FRP bars and FRP laminates. URM walls reinforced with NSM FRP bars and FRP laminates 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), dimension of the groove and type of embedding material (i.e. epoxy or cementitious-based paste), were studied. Two types of FRP fabrics, glass (GFRP) and carbon (CFRP), were used as externally bonded reinforcement to provide the benchmark. Strength and pseudo-ductility of URM walls were significantly increased by strengthening with FRP bars and laminates. Based on experimental evidence, the paper presents an extensive comparison between the mechanical response of the two reinforcement systems.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
