Behavior of Shear-Critical RC Beams Strengthened with CFRCM

Abstract

Strengthening of RC structures using fiber-reinforced polymer (FRP) systems is a popular rehabilitation technique because of its ease of installation and reduced construction time compared with other methods. Fabric-reinforced cementitious mortar (FRCM) is a new alternative strengthening system with additional advantages including excellent compatibility with concrete substrate and easier postrepair inspection of repaired structures. This paper presents the results of an experimental study on the behavior of shear-critical RC beams strengthened with carbon FRCM (CFRCM) composite systems. Six large-scale shear-critical RC beams were tested. The test variables included the amount of internal transverse reinforcement and CFRCM strengthening. The test results indicated that CFRCM strengthening is effective in enhancing the load-carrying capacity of shear-critical RC beams. However, the effectiveness of CFRCM strengthening decreased with the presence of stirrups and slightly reduced the shear-strength contribution from internal stirrups. The experimental shear-strength contributions were also compared with theoretical predictions using new guidelines from the American Concrete Institute. Finally, the shear transfer mechanism in the CFRCM layer was discussed.