This study investigates the structural behavior of concrete beams reinforced with conventional steel and a novel hybrid natural–synthetic fiber reinforced polymer (FRP) system composed of carbon and ramie fibers. Two beams were tested under four-point bending to evaluate ultimate load, stiffness, and crack behavior. The steel reinforced beam achieved an ultimate load of 99.5 kN, while the hybrid FRP beam reached 94.6 kN, corresponding to approximately 95% capacity of the steel beam. The hybrid beam exhibited slightly reduced ultimate load and a more brittle response but developed a denser network of finer cracks. Finite element modelling (FEM) using ABAQUS with damage plasticity and Hashin criteria successfully captured the structural response and failure trends. The results demonstrated that the feasibility of hybrid natural–synthetic FRP reinforcement and provided a combined experimental–numerical framework for future large-scale investigations.
Dabholkar et al. (Sun,) studied this question.