Shear behavior of concrete beams reinforced with corrosion-resistant and ductile longitudinal steel-FRP composite bars and FRP stirrups

Abstract

Inheriting excellent corrosion resistance of FRP bars, steel-FRP composite bar (SFCB) has better elastic modulus and ductility, promising to be longitudinal reinforcement for concrete structures in harsh environments. While previous research primarily focused on the flexural behavior of hybrid longitudinal SFCB and FRP stirrups reinforced concrete (hybrid-RC) beams, the study about shear behavior has rarely been reported and valuable experimental observations are limited. The unique mechanical properties of SFCB causes the inapplicability of existing shear design method and the risk of brittle shear failure. Here, a simplified shear design method is proposed for hybrid-RC beams by analytical investigation and the shear behavior of hybrid-RC beams is investigated experimentally. Results show that SFCB exhibits similar transverse shear behavior to steel bar. Compared with steel bars reinforced concrete beams, hybrid-RC beams based on the proposed design method have better shear performance including same failure modes, similar deflection, narrower shear crack, and higher shear capacity, due to the post-yielding stiffness of SFCB. Furthermore, a modified calculation method of the shear capacity for hybrid-RC beams is proposed, exhibiting great feasibility and accuracy. These results can provide valuable experimental observations of shear behavior and promote the development of shear design tactics for hybrid-RC beams.