Torsional Strengthening of RC Beams with Continuous Spiral Near-Surface Mounted Steel Wire Rope

The strength of reinforced concrete members can be enhanced using externally bonded reinforcement (EBR) and near surface mounted (NSM) methods. However, small number of studies has adopted the NSM method for torsional strengthening. To date, no study has examined the use of spiral NSM steel wire rope and epoxy adhesives for torsional strengthening. Therefore, this study examines the behaviour of RC beams subjected to the combined actions of torsion and bending moment when they are strengthened with spiral NSM steel wire rope (Ø8 mm) in different configurations. For this purpose, six beams of 15 cm × 25 cm × 200 cm were casted. One of these beams was conventional, whereas all the other beams were strengthened with spiral NSM steel wire rope. During the testing process, the twist angle at the torque intervals, first cracking torque, ultimate torque and ultimate twist angle of the conventional beam were compared with those of the strengthened beams. The torsional performance of the RC beams was significantly improved using spiral NSM steel wire rope in various spiral NSM configurations.