Finite element analysis of ductility and flexural capacity of FRP and steel bars hybrid reinforced concrete beams

To study the flexural behavior of hybrid reinforced concrete (hybrid-RC) beams with FRP and steel bars, this paper used ABAQUS finite element (FE) software to model and nonlinear analyze the hybrid-RC beams and investigate the effects of effective reinforcement ratio, concrete strength, and FRP bars type on the flexural behavior of hybrid-RC beams. In addition, the FRP bars stress, flexural bearing capacity, and ductility formulas for hybrid-RC beams were fitted based on the FE results, and existing literature data were used to verify their accuracy. The FE model results indicated that the effective reinforcement ratio, FRP bars type, and concrete strength significantly impacted the flexural bearing capacity and deformation performance of hybrid-RC beams. Increasing the strength of concrete improved the flexural bearing capacity and ductility of hybrid-RC beams; increasing the effective reinforcement ratio and the elastic modulus of FRP bars increased the flexural bearing capacity of the hybrid-RC beams but decreased its ductility. In addition, the fitted FRP bars stress, flexural bearing capacity, and ductility calculation formulas can quickly and conveniently predict the flexural bearing capacity and ductility of hybrid-RC beams.