Torsional Behavior of Reinforced Concrete Beams Strengthened with FRP Composites

ABSTRACT

Fiber Reinforced Polymer (FRP) as an external reinforcement is used extensively to address the strength requirements related to flexure and shear in structural systems. But the strengthening of members subjected to torsion is yet to be explored. In this paper, the behavior and performance of reinforced concrete members strengthened with externally bonded Glass FRP (GFRP) sheets subjected to pure torsion is presented. The variables considered in the experimental study include the fiber orientation, the number of beam faces strengthened (three or four), the effect of number of FRP plies used, and the influence of anchors in U-wrapped test beams. Experimental results reveal that externally bonded GFRP sheets can significantly increase both the cracking and the ultimate torsional capacity. Predicted strengths of the test beams using the proposed theoretical models were found to be in good agreement with the experimental results.

Keywords 

Composites, Fiber Reinforced Polymer, Reinforced Concrete Beam, Strengthening, Torsional Moments, Twist Deformation