Title: Horizontal Shear Capacity of Composite T-beams Reinforced with GFRP Interface Shear Reinforcement

Author(s): Moataz Mahmoud, Mohamed Eladawy, Basil Ibrahim, and Brahim Benmokrane

Publication: Structural Journal

Volume:

Issue:

Appears on pages(s):

Keywords: analytical equations; design codes; composite RC T-beam; crack pattern; glass fiber-reinforced polymer (GFRP) bars; interface shear stress; reinforced concrete; shear reinforcement and connectors; shear stress and slip

DOI: 10.14359/51740718

Date: 3/22/2024

Abstract:
Composite construction has proven to be cost-effective as this method merges precast and cast-in-place elements while preserving the effectiveness and seamless nature of monolithic construction. There are no experimental research results on the behavior of glass fiber-reinforced polymer (GFRP) reinforced composite beams in the case of horizontal shear transfer in composite T-beams. This research aims to investigate a novel and sustainable approach using noncorroding GFRP as shear transfer reinforcement in composite reinforced concrete (RC) T-beams. A total of six full-scale RC T-beams (one monolithic RC beam and five composite RC beams) measuring 4200 mm (165.4 in.) in length, 420 mm (16.5 in.) in depth, and 250 mm (9.8 in.) in width were constructed and tested until failure. The main experimental variables evaluated were shear-reinforcement type (GFRP or steel stirrups); ratio (0.32%, 0.35%, or 0.48%), and shape (stirrups or bent bars). The test results were analyzed in terms of ultimate horizontal shear stress; deflection; slippage; and reinforcement strain. The experimental results indicate that the GFRP shear reinforcement provided adequate shear transfer capacities compared to steel when provided across rough concrete interfaces. Moreover, the test results show that increasing the shear reinforcement ratio enhanced the performance of the composite RC T-beams in terms of horizontal shear capacity and slip. Furthermore, the available equations specified in design provisions such as CAN/CSA S6-19 (2019) and AASHTO LRFD (2018) exhibited unduly conservative predictions of the interface shear strength of the GFRP bars. The results of this study unequivocally establish the viability and promise of employing GFRP bars as shear connectors in composite T-beam applications.