Flexural behaviour of hybrid (FRP/steel) reinforced concrete beams: a review

Abstract

Corrosion on steel reinforcement has a substantial effect on the total lifespan of concrete buildings over time. As a result, researchers are looking at different methods to combat this issue. As a consequence of their remarkable mechanical qualities and resistance to corrosion, fibre-reinforced polymer (FRP) composite bars have gained a large amount of interest from the construction sector. In the construction of reinforced concrete (RC) structures, FRP bars may be used as an alternative to the conventional steel bars. Although the use of steel is effective, corrosion can cause cracking, spalling, and separation of steel bars in RC. Compared to steel-RC beams, FRP-RC beams deflect and shatter more due to their lower modulus of elasticity and a high prevalence of broad cracks than steel-reinforced beams. Also, FRP bars' tensile strength at bent portions is 40-50% lower than that of straight bars. This study aims to evaluate the use of hybrid steel and FRP to reinforce concrete members, avoiding the disadvantages of using one of them as a reinforcement. The results showed that using hybrid reinforcement (steel/FRP bars) in structural components seems to improve building system efficacy by increasing load capacity, ductility, serviceability, and corrosion resistance. This technique can save maintenance costs, extend infrastructure life, and improve sustainability. Also, when the FRP to steel ratio is properly balanced, a desired level of ductility and moment redistribution can be achieved. Additionally, this study suggests conducting more investigations to determine the serviceability and structural properties of combining these materials in the long term.