Comparison of TRM and FRP in Torsional Strengthening of RC Beams Using Carbon Fibers Under Repeated Loads

This article investigates the effectiveness of textiles reinforced mortar (TRM) and fiber reinforced polymer (FRP) in torsional enhancing of RC beams subjected to cyclic loads due to the continuous process of loading and unloading, environmental degradation, ageing, and lack of maintenance, rustled to structural deficiencies may occur in several infrastructures such as multi-story parking garages, ports, bridges, and airport facilities. The factors that were taken into consideration were the kind of strengthening techniques (TRM vs. FRP), the configuration of the strengthening (partially vs. entirely), and the inclination of the strengthening (45° vs. 90°). Seven full-scale specimens were cast and tested until they failed. There was one specimen that served as a reference, three that were reinforced with TRM and three that were reinforced with FRP. The main findings were as follows: (a) Both TRM and FRP composites enhanced torsional capacity to a comparable extent. (b) In both systems, partially strengthening configurations increased torsional capacity more than fully strengthening configurations. (c) In both techniques, the 90° strengthening inclination improved torsional capacity more than the 45° strengthening inclination. (d) Specimens enhanced with TRM and FRP failed in several ways, such as fibers slipping through mortar, fiber rupture with concrete crushing, and deboning from the concrete substrate.