Near free-edge stresses in FRP-to-concrete bonded joint due to mechanical and thermal loads

Over the last few decades, a considerable amount of theoretical and experimental investigations have been conducted on the mechanical strength of composite bonded joints. Nevertheless, many issues regarding the debonding behavior of such joints still remain uncertain. The high near free-edge stress fields in most of these joints are the cause of their debonding failure. In this study, the performance of an externally bonded fiber-reinforced polymer (FRP) fibrous composite to a concrete substrate prism joint subjected to mechanical and thermomechanical loadings is evaluated through employing the principles of lamination theory. An inclusive Matlab code is generated to perform the computations. The bond strength is estimated to take place in a region- also termed the boundary layer- where the peak interfacial shearing and transverse peeling stresses occur; whereas the preceding stress field is observed to be the main failure mode of the joint. The proposed features are validated through the existing experimental data points as well as the commercial finite element (FE) modeling software Abaqus. Comparison between the calculated and experimental results demonstrates favorable accord, producing quite a high average ratio. The current approach is advantageous to failure modeling analysis, optimal design of bonded joints, and scaling analyses among others.