Numerical study on the torsional behavior of CFRP-strengthened RC beams

The present paper offers a numerical study on the behavior of reinforced concrete (RC) beams strengthened with carbon fiber reinforced polymer (CFRP) under pure torsional loading. The failure mode of RC beams significantly changed in accordance with torsional loading. Therefore, the effect of strengthening RC beams by CFRP under torsion is a vital area of study. This paper attempted to fill the gap by conducting a numerical (Abaqus) study, whereby the numerical investigation was in line with the parametric for a previous study of an experimental program. The numerical model achieved agreement with the results of the experimental program, then, this model was used by applying CFRP, instead of GFRP. Additionally, the numerical study was completely in line with the parametric study in terms of sample dimensions, steel reinforcement, number of FRP layers, and width of FRP strips, for the aim of comparing results. The comparative evaluation in this study aims to contrast the behavior of RC beams strengthened by CFRP with the behavior of those strengthened by GFRP under pure torsion. Parameters such as ultimate torsional moment, and the maximum angle of twist were studied. The study revealed that strengthening with CFRP improved the ultimate strength and post-cracking stiffness, in addition to localizing the damage.