Theoretical Analysis And Numerical Simulation On Flexural Performance Of FRP-concrete Composite Beam

Due to the high strength and good corriosion resistance, FRP (Fiber Reinforeed Polymer) has gained more and more attention in civil engineering especially in the field of structure strengthening, but few studies is available in the component constructed with FRP. In this thesis, a new kind of FRP-concrete composite beam was investigated, and theoretical analysis and finite element simulation on flexural performance of FRP-concrete composite beam were carried out.The main research work was as follows:(1)Based on the wide range of the domestic and overseas literatures, the research status of FRP-concrete composite beams is discussed in a comprehensive review and summary. Starting from the perspective of microcosmic mechanics, the mechanical characteristics of each part was analysed, then from the perspective of macroscopic mechanics, elastic constants of FRP (orthotropic materials) was analysed. On the basis of a lamina, further analysis of the overall mechanical characteristics of laminates was carried out.(2) According to the mechanical characteristics of composite beams, possible failure modes of composite beams were considered, and then analyzed theoretically. For the FRP-concrete composite beams with reinforcement, there are three kinds of failure modes, while for the FRP and concrete composite beams without reinforcement, there are two failure modes. Based on the analysis of calculation model of different types of failure mode, the theoretical formulas of ultimate bearing capacity of FRP-concrete composite beams in these kinds of situations were proposed.(4) Finite element analysis was carried out based on the GFRP reinforced RC beam under bending.The finite element result agrees well with the experimental values, which proves that the method in this thesis is reasonable and reliable.16 kinds of FRP-concrete composite beams were designed under four-point bending load, steps of using ABAQUS to model were analyzed. Finite element analysis results were analysed. Two kinds of failure mode for FRP-concrete composite beams were given in this thesis. The flexural bearing capacity of different beams and middle span displacement, bending and shear failures are analyzed, the stress and strain of the concrete and of FRP in the two typical failure mode of were compared. The effects of flexural properties of FRP and concrete composite beams were analysed, including FRP layers, reinforcement ratio, concrete strength, orientation of the fiber. The finite element analysis results were compared with the results of calculated according to the derivated formulas in chapter 3. It can be seen that for the ultimate bearing capacity, the finite element analysis results and calculated results are in good agreement.