Non lineer finite element analysis of concrete beams strenghthened with carbon fiber reinforced plastics

Retrofitting reinforced concrete structures with carbon fibre reinforced plastic has become main subject of many experimental studies. Stress and strain distribution over concrete-CFRP interface mostly governs the behaviour of this composite system. A finite element model, after being verified with experimental results, creates the possibility of making model simulation of experiments. In order to verify the finite element model, making use of the special element types of ANSYS program, a finite element model of experiment beams is constructed and load displacement behaviour is compared with the experiment resuls to check the extend of differences between experiment and analysis results. After obtaining a verification, the computer analysis of experiment beams is used together with computer simulations to obtain strain distribution in the CFRP-concrete interface and eventually effective CFRP length. A need for using special contact surface is pointed out. The effect of increasing CFRP bond lenght on strain distribution and maximum load is investigated and effective bond lenght obtained from these observations are found to be in good agreement with experimental findings.