Repairing of RC Beams with Openings Subjected to Torsion Using CFRP

Web openings in beams occur quite often in construction to accommodate essential services such as electricity, and water supply, and IT services. Beams may need to be repaired and rehabilitated to improve their properties such as torsional strength and strength capacity to survive the additional loads place on existing structure parts. In this study, an experimental program was conducted to study the behavior of beams with openings subjected to torsion. The effect of repairing such beams using carbon fiber reinforced polymers (CFRPs) is investigated. Seven RC beams were examined, each with an identical cross-sectional area of 150 x 350 mm, and a 1400 mm total span. The effects of CFRP configuration, opening width and CFRP layers were examined in this study. The control specimens were loaded to failure, while the other specimens were loaded until diagonal cracking occurred due to torsion; they were then repaired with CFRP and retested. The experimental results showed that the opening presence in beams decreased the cracking and ultimate torque. Repairing the beam specimens with CFRP improved the ultimate torque and ultimate rotation angle. Using vertical CFRP configuration in repairing beams with openings improved the ultimate torque more than using inclined CFRPs.