Shear behavior of RC T-beams externally strengthened with anchored high modulus carbon fiber-reinforced polymer (CFRP) laminates

This work presents the results of an experimental study on the effect of shear strengthening of reinforced concrete (RC) T-beams with high modulus carbon fiber-reinforced polymer (CFRP) laminates and anchors. The parameters considered were the anchor insertion angle and dowel diameter. Experimental results showed that the addition of U-wraps led to a 61% increase in shear strength compared to the control specimen, but failure was dominated by the brittle debonding of the CFRP laminates, with no ductility exhibited prior to failure. Anchoring the CFRP laminates with CFRP spike anchors further enhanced the shear capacity of the Uwrapped specimen by 14-51% and improved the shear contribution of the FRP by 36-136%, respectively. In addition, the CFRP anchorage system highly utilized the strain in the CFRP laminates and substantially enhanced the ductility of the specimens. A comparison between the shear resistance provided by the FRP reinforcement of the tested specimens and predicted capacity using current design guidelines showed that the current provisions could be safely applied to design RC T-beams strengthened in shear with anchored CFRP Uwraps.