Crack-based evaluation of deep concrete members reinforced with FRP bars

Abstract

Conventional steel-reinforced concrete deep beams are typically known for their high shear strength and stiffness. To avoid corrosion-related deterioration problems, fiber-reinforced polymers (FRPs) reinforcement bars have been used as non-corrosive substitute for steel. However, tests on deep beams reinforced with internal FRP reinforcement have shown that such members can exhibit different failure modes than the ones observed in conventional deep beams. Moreover, these failure modes may limit the shear capacity making the technical solution less feasible. This study proposes to develop a kinematics-based model capable of predicting the complete shear behavior of FRP-reinforced deep beams without web reinforcement. The approach includes modelling features for three different failure modes, accounting for the effects of FRP reinforcement on the observed behavior of deep beams. The crack-based 2PKT for FRP-reinforced deep beams is applied to tests from the literature resulting in an average experimental-to-predicted strength ratio of 1.06 and a coefficient of variation of 8.5%. Furthermore, the developed kinematics-based model is able to adequately predict the failure mode, as well as global and local deformations along critical cracks.