Experimental Investigation on Bond of NSM Strengthened RC Structures

Near Surface Mounted (NSM) FRP reinforcement is being increasingly recognized as a valid alternative to externally bonded reinforcement (EBR) for enhancing the flexural strength and shear resistance of deficient reinforced concrete members. As this technology emerges, the structural behaviour of NSM FRP strengthened elements needs to be characterized, and bond between NSM FRP bars and concrete is the first issue to be addressed. This paper presents, as part of a study in the framework of a Round Robin Testing (RRT) programme, the results of a series of 27 double shear bond tests on NSM FRP strengthened concrete. Aim of this project is to investigate the feasibility of the adopted test method and to investigate the mechanism of bond between NSM reinforcement and substrate material. Experimental results confirm the efficiency and re-liability of the test method and the bond effectiveness of the NSM technique for strengthening RC members.