The Non-Linear Finite Element Analyses Of CFRP-Reinforcement Of RC Beam

Using Carbon fiber reinforced polymer sheets (CFRP) to reinforced concrete structures is a new and hi-tech method and becoming more and more popular in recently decades. Therefore, the reinforcement theory and technology have been rapidly developing. On the other side, the finite element analysis (FEA) makes an offer of a favorable tool for the CFRP reinforcement in structure because of its maturity. The FEA can not only be used to simulate the behavior of structure reinforced with CFRP, but also provides a valuable supplement to laboratory investigations, particularly to applications in civil engineering.Basing on theory of the non-linear FEA, a program was written, which can be used to analyze CFRP strengthened reinforced concrete beam. And the principle and method used to write the program was introduced in this paper. The main content is as follow:1. Concrete uses rectangle element, steel and CFRP use linear element, at the same time, double-spring element was used to simulate the slipping between steel and concrete, and the slipping between CFRP and concrete;2. Constitutive relationship of concrete is D-P model and K-G failure criterion and Houde-Mirza slipping theory was adopted in the program;3. Bilinearity displacement model was used in this paper and stiffness matrix to rectangle element was deduced with principle of virtual work;4. The result indicates that the concrete strengthen, the strength of extension of CFRP and the ratio of longitudinal rod of component reinforced are the main factors affected the reinforced result;5. Through analyzing the situation of reinforced structure, it can be concluded that secondary loads is unfavorable in reinforcing structures with CFRP, especially when the first stage loads is large enough. So the first stage loads should be unloaded before reinforcement possibly;The program's functions and characteristic:1. It can be used to analyze the ordinary RC beams2. It can be used to analyze the RC beam reinforced with CFRP or other sheet in bending resistance;3. It can also be used to analyze the RC beam reinforced under first stage loads;4. Being friendly, simple and with visualized interface the program can be conveniently and easily operated;5. The program can give the picture of failed element, cracks picture at every step of load and load-deflection curves.