A nonlinear analytical model for predicting bond behavior of FRP-to-concrete/steel substrate joints subjected to temperature variations

The effective interfacial stress transfer mechanism plays an important role in the mechanical performance of externally bonded fiber reinforced polymer (FRP) strengthened structures. Therefore, a profound understanding of the effect of temperature variation on the bond behavior of FRP-to-concrete/steel joints is helpful to improve the engineering specification of FRP strengthening technology. This paper presented a new analytical approach aimed at predicting the bond and debonding behavior of FRP-to-concrete/steel bonded joints under thermal loading. The proposed analytical solutions were derived based on an exponential temperature-dependent bond-slip model, and these solutions had a rather good prediction accuracy compared with the experimental and finite element numerical results. Some discussions about the bond behavior under temperature variations were carried out with an example. Results of this study showed that with the increase of bond length, there existed an upper limit value for the failure temperature variation, as well as for the maximum FRP stress. Temperature-dependent bond-slip relation was shown to have a great effect on the distribution of FRP stress and interfacial bond stress, especially on the temperature variation–free end slip response.