Non-linear Finite Element Analysis Of RC Beams Flexurally Strengthened With FRP

As a new strengthening technique, bonding FRP(Fiber Reinforced Plastic) sheets to the tensile face of structures(especially reinforced concrete structures) can improve their load-carrying capability and serviceability. Attributing to the light-weight, high-quality strength, better workability, corrosion resistance, good durability of FRP, this strengthening technique is being increasingly used in civil engineering. Research on FRP-Flexural-strengthened RC beams, which is an important field of this technique, has gained some achievements, however, there are still some problems needed to be concerned, such as experiment of RC beams strengthened with prestressed FRP and non-linear finite element analysis of RC beams strengthened with FRP.Non-linear FEA can offer a lot of feedback messages, such as stress, strain and deformation of structures, so it can take the place of some experiments in research, and can be used in design and prediction for engineering. In this thesis, a proper FE model was tried to be established in order to simulate the failing process of RC beam strengthened with FRP. RC beam strengthened with FRP is a composite structure with some kinds of material, which leads to its complex mechanics of failure. So there is some difficulty in numerical simulation. Considering of these, Numerical shear tests were firstly carried out to get the parameters of interfacial concrete, which can reflect the mechanical properties of FRP-concrete interface properly. Secondly, based on the parameters of interfacial concrete and discrete crack, a FE model for FRP-strengthened RC beam was established. The model can simulate all of the failure models of the RC beams strengthened with FRP, including the rupturing failure model and debonding failure model. The numerical results were in good agreement with the experimental results, which indicated that the FE model was quite reasonable.Finally, the FE model was used to simulate the experiments from other literature, and the good agreement with each other showed that the FE model was reasonable and applicable. This model can be used in strengthening design, prediction of ultimate load and optimize of strengthening schemes.