Bond Behavior of Prestressed CFRP Strips-to-Concrete Joints Using the EBROG Method: Experimental and Analytical Evaluation

7 Fiber-reinforced polymer (FRP) composites are widely employed as externally bonded reinforcement 8 (EBR) systems for strengthening of reinforced concrete members. More recently, a new technique, re-9 ferred to as externally bonded reinforcement on grooves (EBROG), has been proposed, which is based 10 on using a number of grooves throughout the concrete substrate with the aim of enhancing the bond 11 strength between the FRP composite and concrete. This study investigates the influence of groove depth 12 on the resulting debonding process that can be observed in prestressed carbon FRP strips. To do so, 13 prestressing force release tests were conducted on a series of EBR and EBROG FRP strips bonded to 14 concrete specimens. Test results demonstrated that the fracture process leading to debonding of the 15 EBROG specimens developed in a significantly different manner with respect to the case of EBR spec-16 imens. Specifically, fractures ran through deeper layers of concrete as the grooves became deeper. Nu-17 merical analyses are also proposed to scrutinize the actual bond-slip law characterizing both EBR and