Finite Element Modeling of FRP-Strengthened RC Beam under Sustained Load

External bonding of FRP laminates to the tension soffit of concrete members has become a popular method for flexural strengthening. However, the long-term field performance of FRP-strengthened RC members under service conditions is still a concern, and more work needs to be done. Based on concrete smeared-crack approach, this paper presents a finite-element (FE) model for predicting long-term behavior of FRP-strengthened RC beam, which considers the time-dependent properties of all components including the aging effect of concrete. According to the comparison between theoretical predictions and test results, the validity of the FE model is verified. The interfacial edge stresses in adhesive layer were determined through appropriate mesh refinement near the plate end, and their time-dependent characteristics were investigated. The results show that creep of concrete and epoxy resin cause significant variations of the edge stresses with time. According to the research in this paper, the FE approach is found to be able to properly simulate the long-term behavior of the FRP-strengthened beam and help us better understand the complex changes in the stress state occurring over time