Development of a simplified bond model used for simulating FRP strips bonded to concrete

The key to the simulating of FRP-strengthened concrete structures with commercial finite element (FE) software is capturing the bond behavior of the FRP-concrete interface. Based on the experimental results captured by the digital image correlation (DIC) technique, this paper presents a bilinear bond model to simulate the interfacial bond. A computational model has been also presented to (1) evaluate the proposed and some other existing bond models used for simulating the interface of the FRP-concrete bond, and (2) predict the load-slip relation of the FRP strip. Comparisons between simulations and the corresponding tests show better accordance by using the proposed model, indicating its reliability. The numerical results from specimens using various strip properties (width, thickness, modulus and bond length), prism widths and concrete strengths are in close agreement with experimental data, further validating the proposed model. The sensitivity of computational results to element size is also examined.