Effect of the EBROG method on strip-to-concrete bond behavior

Abstract

The bond behavior of precured FRP strips and steel plates to concrete substrate was investigated in this research in terms of the load capacity, slip and strain distribution and debonding mechanism. Experimental single lap shear tests were performed and an experimental-analytical model was proposed to determine the bond strength of the FRP-bonded joints. Two strengthening methods, including externally bonded reinforcement (EBR) and externally bonded reinforcement on groove (EBROG), were compared. A two-dimensional digital image correlation (2D-DIC) system was utilized to measure the full-field deformations.Compared to the 90 mm effective bond length for the EBR method, the effective bond lengths for the EBROG method were equal to 145 and 160 mm for 5 × 5 and 5 × 10 mm groove cross sections, with 92% and 112% higher loads, respectively. In addition, the results showed that the EBROG method improved the bond resistance of steel-to-concrete joints, but it was not as efficient as it was for the FRP-to-concrete bonded joints. Furthermore, the crack propagation underneath the strip was assessed for the first time for the EBROG method, by using a side-view measurement.