Effect of Groove Depth on Behavior of Prestressed CFRP Strips Bonded to Concrete by Using EBROG Method

Moshiri N., Czaderski C., Mostofinejad D., Hosseini A., Motavalli M.

10th International Conference on Fibre-Reinforced Polymer (FRP) Composites in Civil Engineering (CICE), İstanbul, Turkey, 8 - 10 December 2021, vol.198, pp.2188-2196 identifier identifier

  • Publication Type: Conference Paper / Full Text
  • Volume: 198
  • Doi Number: 10.1007/978-3-030-88166-5_189
  • City: İstanbul
  • Country: Turkey
  • Page Numbers: pp.2188-2196
  • Keywords: EBROG, Prestressed CFRP strip, Bond behavior, Groove depth, TO-CONCRETE
  • Istanbul Technical University Affiliated: No


The efficiency of externally bonded reinforcement on groove (EBROG) method to improve the bond behavior of non-prestressed fiber reinforced polymer (FRP) composites to concrete has been so far demonstrated in several research studies. Recently, the performance of EBROG method has been investigated to enhance the bond resistance of prestressed FRP strips to concrete. In the current study, the influence of groove depth on bond behavior was examined. For this purpose, EBROG method with various groove depths was used to strengthen concrete prisms and its performance was compared with that of the conventional externally bonded reinforcement (EBR) method. Prestress force-release tests were conducted to study the bond behavior of prestressed carbon FRP (CFRP) strips to concrete. Experimental results showed that the bond resistance of EBROG joints increased to more than 200%, compared to that of the EBR joints. EBR joints exhibited an average bond resistance of 34.4 kN, while EBROG method with 10 x 5 and 10 x 10 mm (width x depth) groove dimensions led to average bond resistances of 72.0 and 81.4 kN, respectively. Therefore, for the grooves dimensions used in this study, it can be concluded that the deeper the grooves, the higher the bond resistance in a prestress force-release test. In addition, it was observed that the failure in EBR and EBROG was governed by the debonding of the prestressed strip from the concrete substrate. However, when EBROG method was used, cracks were developed in concrete depth and width, outside the bond area. Considering the failure plane in each specimen, an analytical procedure was proposed to predict the bond resistance of prestressed CFRP strips to concrete. Good agreement was observed between the proposed analytical model and the experimental results.