Investigating the optimal CFRP wrapping orientation for enhanced torsional strength in RC beams

Abstract

The aim of this study is to find the optimal wrapping orientation of Carbon Fiber Reinforced Polymer (CFRP) to increase the torsional strength of reinforced concrete (RC) beams under pure torsion. The use of CFRP materials to increase the flexural and shear strengths of RC beams is common, but its potential for torsional improvement is still less well-established. The behavior of RC beams reinforced with CFRP under pure torsion in different orientations is the main focus of this work. A control beam and three beams wrapped with CFRP in various orientations—fully wrapped, 90 ° vertical wrapped strips, and 45 ° inclined wrapped strips were modeled numerically. Each beam had same dimensions of 150 × 230 × 1500 mm. The ultimate torque, angle of twist, and cracking angle were measured for each beam. According to the results, CFRP considerably increased torsional strength in comparison to the control beam. The 90 ° vertical wrapped strip beam decreased the angle of twist by 66.33%, but the fully wrapped CFRP beam increased the ultimate torque by almost 75.28%. The 45 ° inclined wrapped strip beam showed an optimal performance compared to fully wrapped CFRP beam and 90 ° vertical wrapped strip beam by increasing the torque capacity by 23.85% and decreased the angle of twist by 32.65%. Analytical calculations and experimental work from the literature were used to validate these conclusions. ABAQUS software was used for the numerical investigation. This research underscores the potential of different CFRP wrapping orientations as a resilient solution for improving the torsional strength of RC beams, offering a valuable approach for enhancing the structural integrity and durability of reinforced concrete structures in torsion-prone environments.