Experimental Study of the Behavior of GFRP Reinforced Concrete Corbels

Lately, there has been a growing use of FRP rebars (fiber reinforced polymer rebars) in structural components. To understand the complex behavior of these structures under loading, experimental studies are necessary. This article presents an experimental analysis of four double-sided concrete corbels reinforced with glass fiber-reinforced polymer (GFRP) bars and no web reinforcement, focusing on the effects of longitudinal reinforcement ratios and shear span to effective depth ratios (a/d) on structural performance. Two a/d ratios (0.7 and 1.0) and two values of longitudinal GFRP reinforcement ratios (ρf = 0.56% and ρf = 0.87%) were tested to compare the shear behavior of the corbel specimens. The failure modes, stiffness, load-displacement curves, and diagonal strut mechanism are discussed. The results reveal that the splitting mode of failure and the diagonal strut mechanism become dominant once inclined cracks appear. While both the a/d ratio and GFRP reinforcement ratio influence the behavior of GFRP-reinforced concrete corbels, the a/d ratio has a more pronounced effect on shear resistance, whereas the GFRP reinforcement ratio has a lesser impact on shear strength. Additionally, the ACI 440.1R-15 guidelines for predicting the shear strength of GFRP-reinforced concrete corbels were found to provide overly conservative estimates.