Practical evaluation of high-strength concrete corbels reinforced with GFRP bent bars

Abstract

Corbels, designed primarily as discontinuity-region structural elements, are often used as components of bridges and buildings to support beams and girders. There has been extensive research on steel-reinforced concrete (RC) corbels; however, there is a noticeable gap in research to investigate the behavior of glass fiber-reinforced polymer (GFRP)-RC corbels. Considering the linear stress–strain relationship up to failure of GFRP, the use of high-strength concrete (HSC) in lieu of the normal-strength concrete (NSC) in corbels would reduce their sizes considerably; yet it will aggravate their brittle nature. In this study, nine full-scale concrete corbels were constructed and tested until failure. One reference specimen was reinforced with steel bars, while the other eight were GFRP-RC corbels. The main test parameters were the type of concrete (HSC or NSC), the shear span-to-depth ratio, and the total reinforcement ratio of the main and horizontal bars. The tests showed that the principal mode of failure was concrete strut crushing for specimens with a shorter shear-span-to-depth ratio. The steel-RC corbels failed by tension tie yielding, which showed large ductility. The Canadian standards for FRP-RC building structures predicted a conservative mean capacity with Ppre/Pexp ratio of 0.59 compared to the American code and Eurocode, which overestimated the capacities with a ratio of 1.18 and 1.25, respectively.