Innovative FRP shear strengthening of RC structural walls using EBROG method and FRP spike anchors: An experimental and theoretical study

This research investigates the application of fiber-reinforced polymer (FRP) installed by the novel externally bonded reinforcement on grooves (EBROG) method, combined with FRP anchors, to strengthen reinforced concrete (RC) shear walls with a shear failure mode. Traditional externally bonded reinforcement (EBR) systems often suffer from premature debonding of FRPs, limiting their efficiency in shear strengthening. In contrast, the EBROG technique enhances the bond mechanism by connecting FRP sheets into grooves, ensuring improved load transfer and enabling full utilization of FRP materials. Moreover, the effectiveness of FRP anchors in preventing delamination and enhancing shear resistance is also examined. This study presents the first experimental investigation into the use of the EBROG technique for improving the shear performance of RC shear walls prone to shear failure. A total of four large-scale wall specimens comprising one control and three strengthened configurations were tested under combined cyclic lateral and constant axial loading to examine their structural response. Among the strengthened specimens, SSW2 incorporated four FRP spike anchors placed at the bottom end of the wall on each side, while SSW3 included additional through-thickness anchors at both ends. The results show that the most comprehensive FRP configuration (SSW3) improved lateral load capacity by 55 %, enhanced ductility by 78 %, and increased cumulative energy dissipation by 372 % compared to the control specimen.