EBROG and EBRIG methods for strengthening of RC beams by FRP sheets

Abstract

This paper presents an experimental study on reinforced concrete (RC) beam specimens flexurally strengthened by fibre-reinforced polymer (FRP) sheets using conventional externally bonded reinforcement (EBR) method and recently introduced grooving method (GM) in the form of externally bonded reinforcement on grooves (EBROG) and externally bonded reinforcement in grooves (EBRIG) techniques. The concrete beam specimens were strengthened with one, two or three FRP layers, and their load–displacement relationships as well as their failure loads were compared with each other. The performances of EBR, EBROG and EBRIG techniques for flexural strengthening of RC beams were found to be very close when one layer of FRP sheet was used; however, for two FRP layers, beams strengthened with GM in the form of both EBROG and EBRIG techniques experienced up to 25% higher ultimate loads compared to those strengthened with EBR method. Furthermore, for three FRP layers, this increase was 19 and 24%, respectively, for EBROG and EBRIG strengthening techniques compared to EBR method.