Effect of GFRP Anchor on the Performance of Reinforced Concrete Beams to Mitigate The Debonding Failure

Strengthening reinforced concrete (RC) beams using fiber-reinforced polymer (FRP) materials has become a widely accepted technique in structural engineering due to its efficiency, light weight, and resistance to corrosion. Among these materials, glass fiber-reinforced polymers (GFRP) are commonly used for flexural strengthening by bonding fabric sheets to the tension side of beams using epoxy adhesives. In this study, an experimental program was carried out to investigate the flexural behavior of an RC beam strengthened with a GFRP fabric sheet bonded to its bottom surface using epoxy. The beam was tested under three-point bending conditions, with simple supports and a single central point load, to simulate a standard flexural loading scenario. During loading, premature debonding between the GFRP sheet and the concrete surface was observed at advanced stages, leading to slip and reduction in strengthening efficiency. To mitigate this issue, GFRP anchors, made from the same material as the strengthening sheet were introduced to improve the bond. These anchors had varying dimensions in width and height to assess their influence on the overall performance of the beam. The results revealed that both the load-carrying capacity and displacement capacity of the beam increased significantly with the addition of the anchors. The most effective improvement occurred when the anchor width was maximized and the height remained lower than the width, suggesting that wider and flatter anchors enhance bond performance more effectively. A clear proportional relationship was found between anchor width and the beam’s structural performance, while increased anchor height showed a diminishing effect. These findings highlight the critical role of anchor geometry in optimizing the performance of GFRP-strengthened RC beams.