Performance of GFRP RC Deep Beams with Web Reinforcement

Corrosion in steel-reinforced concrete has long been a challenge, leading researchers to explore alternative materials like Glass Fiber-Reinforced Polymer (GFRP) bars. These bars are non-corrosive and non-magnetic, offering higher tensile strength and a better strength-to-weight ratio than traditional steel. As a result, they are increasingly used in bridges, pavements, and parking garages. While design codes like ACI 440.11-22 and CSA S806-12 provide guidance for GFRP reinforcement, they offer limited coverage for deep beams. In addition, there is limited research on how web reinforcement affects the shear performance of GFRP-reinforced deep beams. This study investigates the shear behaviour of high-strength concrete (HSC) deep beams reinforced with GFRP bars using different web reinforcement configurations. The study focuses on a single shear span-to-depth (a/d) ratio, testing four beams made with 70 MPa concrete under four-point bending. Results showed that vertical web reinforcement increased shear capacity by 69%, while horizontal reinforcement improved it by 42% and enhanced initial stiffness. The combined configuration had the highest stiffness but slightly lower strength than the vertical-only beam. These findings highlight the significance of web reinforcement in improving the shear strength, stiffness, and crack control of GFRP-reinforced deep beams.