Study On The Technologies And Flexural Behavior Of The RC Beams Strengthened With Prestressing Presoaked Cfrp Laminates

The method of using carbon fiber composite material to strengthen the structure has already been widely applied, but the technique of using prestressed carbon fiber to strengthen the structure has not been extensively used in entitative project. In this thesis, the current research in this filed were firstly analyzed in both domestic and oversea areas. Then an innovative technique and equipment that produces prestressing presoaked CFRP laminates were proposed, and the idea of strengthening construction by using prestressing presoaked CFRP laminates was developed. Furthermore, the flexural behavior and the effect of using prestressing presoaked CFRP laminates to strengthen RC beam were analyzed by three-point bending experiments and FEM simulation. The main results are as follows:Firstly, considering the character of carbon fiber composite material, An innovative technique and equipment that produces prestressing presoaked CFRP laminates were developed. The stretching and anchoring appliance of prestressing presoaked CFRP laminates were also developed (National Patent No: 200910104360). The FEM results prove that its strength could satisfy the working requirements. Through technology test, the appliance exert prestress on presoaked CFRP laminate as required, and the anchoring applice play its function completely.Secondly, through the bending experiment and theory analysis of RC beam, which is strengthened with prestressing presoaked CFRP laminates, The change of flexural behavior of rear beam strengthened with prestressing presoaked CFRP laminates was inspected. The phenomenon of each stage between loading and destruction were observed. Analyse the strengthen RC beam's ultimate loading, deflection and crack graphics change extent under different prestress. The result shows that there is a close relationship between the ultimate loading of prestressing presoaked CFRP-strengthened RC beam and the extent of prestress. Therefore, the more prestress it has, the stronger ultimate loading it will have. Compared with RC beam without strengthened, the cracking loading, yield loading, ultimate loading is increased by 9.39%-85.71%, 10.83%-42.36%, 7.75%-33.17%. Compared with RC beam strengthened with normal presoaked CFRP laminates, the cracking loading, yield loading, ultimate loading is increased by 16.42%-69.78%, 10.65%-28.45%, 7.87%-23.60%. According the observed destructional forms, analyzes the destructional mechanism of prestressing presoaked CFRP laminates strengthened RC beam.Thirdly, Implements numerical simulation on the flexural behavior of RC beam strengthened with prestressing presoaked CFRP laminates through FEM software ANSYS. The calculated effective prestress value is pretty close to theoretical outcome, and preferably fit with RC beam's ultimate load-deflection curve. This illustrates that the method of numerical simulation in this thesis is correct, and it could be used in project design calculation and for the strength of model experience.Finally, the method of strengthening concrete beam bridge with prestressing presoaked CFRP Laminates was probed.