STRENGTHENING OF RC STRUCTURES WITH NEAR SURFACE MOUNTED FRP RODS

ABSTRACT

The use of Fiber Reinforced Polymer (FRP) materials has proved to be one of the most exciting and effective technologies for external strengthening of reinforced concrete (RC) and masonry structures. In this context, Near Surface Mounted (NSM) FRP rods are now emerging as a promising technique in addition to externally bonded FRP laminates. Embedment of the rods is achieved by grooving the surface of the member and placing the rods in the epoxy-filled grooves. The overall objective of this research project was to investigate the effectiveness of NSM FRP rods as a strengthening system for RC and masonry structures. The research protocol started from the characterization of the tensile properties of the FRP rods (material level). Then, the mechanics of the bond of NSM FRP rods embedded in concrete and concrete masonry units was experimentally investigated by using couponsize specimens (sub-system level). Finally, testing of eight full-size RC beams strengthened in shear with this technique was performed (structural member level). Results showed that NSM FRP rods can significantly increase the shear capacity of RC members. A simple shear design approach was developed and, when applied to the tested beams, appeared to give a reasonable and conservative estimate of the ultimate load.