Crack-based modeling of FRP-reinforced deep beams without transverse reinforcement

One cause of deterioration in existing concrete structures is chloride-induced corrosion, which affects the steel reinforcement and its bond with the concrete. To address this issue, alternative types of non-corrosive internal reinforcement have been proposed. One substitute for conventional steel reinforcement are bars made of fiber-reinforced polymers (FRPs). FRP materials are corrosion-resistant and typically possess high tensile resistance, making them a suitable alternative to steel reinforcement. Despite these advantages, FRP reinforcement also present drawbacks such as brittle-elastic behavior, lower modulus of elasticity, and inferior bond properties compared to steel reinforcement. Large-scale tests of deep beams with FRP bars have shown a significant shear strength reduction compared to similar steel-reinforced beams. Therefore, the main goal of this paper is to model the behavior of deep beams reinforced with internal FRP bars. Test specimens from the literature are modeled based on an existing crack-based assessment framework for steel-reinforced members, which is extended to account for the mechanical behavior of FRP bars. The crack-based approach adequately captures the complete response of the investigated deep members, including deformations, shear strength, and the effect of concrete strength on the shear behavior of FRP-reinforced deep beams.