Strengthening of shear critical RC beams with various FRP systems

The use of fiber reinforced polymer (FRP) sheets to shear strengthen reinforced concrete (RC) beams has been studied and proven repeatedly. However, numerous strengthening configurations and materials can be combined to maximize the increase in strength and repair. This study investigates the effectiveness of using commercially manufactured carbon FRP (CFRP), glass FRP (GFRP) and fiber reinforced cementitious matrix (FRCM) sheets to increase the shear capacity of RC shear critical beams. Nine RC shear deficient slender beams were tested. The test variables included the use of three different FRPs (CFRP, GFRP, and FRCM), and the presence and type of FRP anchors (CFRP or GFRP). The experimental results revealed that applying FRP sheets increased the overall shear capacity, full depth u-wrapped FRP sheets perform better over companion partial depth u-wrapped FRP sheets, the use of FRP anchors further improved the shear capacity and ductility of failure, FRP strengthening could change the mode of failure from a shear to flexural failure and FRP debonding was delayed with the presence of FRP anchors. A comparison of the experimental load capacities with predicted values indicates that they correlate well with predictions using the current Canadian design codes.