Evaluation of deflection and flexural performance of reinforced concrete beams with glass fiber reinforced polymer bars

This paper aims to experimentally evaluate the load-deflection curve and flexural performance of reinforced concrete (RC) beams with glass fiber reinforced polymer (GFRP) bars. Twelve RC beams were well instrumented and tested under four-point loading for failure. The RC beams had a constant large scale size of 2400 mm long, 250 mm deep, and 180 mm wide. The main test variables are the reinforcement materials (GFRP and steel bar), the concrete strength (36, 73, and 84 MPa), the GFRP reinforcement ratio (0.39–1.19%), and the GFRP bar diameter (8, 12, and 14 mm). The test results of the RC beams including failure mode, load-deflection response, and nominal moment-materials strain curves were compared and discussed. ACI 440, ISIS, and fib for GFRP RC beams, and ACI 318, CAS A23.3, and EC2 for steel RC beams were evaluated to predict failure modes and flexural capacities. Furthermore, nine theoretical models were applied to find the effective moment of inertia and then to predict load-deflection curves. The ratios of experimental to theoretical results were reported and discussed at service and failure loads. It was found that several models can reasonably predict deflection up to 40% of failure load whereas the majority underestimate the deflections at failure with various accuracies. The experimental results revealed that using high strength concrete significantly improved the failure load up to 28% and reduced deflections and crack widths of GFRP RC beams. •Twelve large scale GFRP and steel RC beams were well instrumented and tested.•The flexural behaviors of GFRP RC beams were improved by HSC compared to NC.•Load-crack width responses and crack characterizations have been presented.•Nine theoretical deflection models have been evaluated by load-deflection curves.•Flexural performance of RC beams was predicted using six international guidelines.