Structural performance and serviceability of concrete beams reinforced with hybrid (GFRP and steel) bars

• Flexural response of hybrid-reinforced concrete beams was investigated.
• Parameters included the reinforcement ratio and the ratio of steel to GFRP bars.
• Code equations were assessed against the experimental test results.
• New bond coefficient proposed to predict the crack width of the hybrid beams.
• New deformability factor proposed to assess the deformability of the hybrid beams.

This paper reports on the structural performance of concrete beams reinforced with hybrid reinforcement. Six concrete beams reinforced with a combination of steel and glass fiber-reinforced polymer (GFRP) bars and three other beams reinforced with only GFRP bars were tested in flexure. Over-reinforced hybrid beams showed higher strength and ductility than their GFRP-reinforced counterparts. The CSA-S806-12 equation accurately predicted the deflections of the hybrid-reinforced beams with high effective reinforcement ratios. Based on the test results, a bond coefficient was proposed to predict the crack width of the hybrid-reinforced beams using the ACI-440.1R-06 equation. A modified deformability factor was also utilized to assess the deformability of the hybrid-reinforced beams. Comparison between the experimental and predicted results showed the adequacy of the models used in predicting the load-carrying capacity, deflection, crack widths, and deformability of hybrid-reinforced concrete beams.