Evaluation of FRP-to-concrete anchored joints designed for FRP shear-strengthened RC T-beams

The objective of this paper is to evaluate the bond performance of different anchorage techniques that can in particular be used for fiber reinforced polymers (FRP) shear-strengthened reinforced concrete (RC) T-beams. The results of two different experimental programs are gathered and compared to highlight some common aspects. Overall, 25 bond tests on FRP-to-concrete joints with test setups that simulate the behavior of an anchored FRP shear-strengthened beam are examined. The anchorage techniques considered are mechanical anchors, FRP bars, longitudinal FRP plates, extensions to the underside of the flange, and carbon FRP (CFRP) ropes. The influence of concrete strength, plate width, bond length, and rope length on bond strength is investigated. Experimental results show that both bond strength and ductility are affected by the anchorage technique used. In light of the experimentally observed failure modes, some bond strength models provided in the literature and design standards are used to predict the maximum bond load of FRP-to-concrete joints and compared with experimental results.