Study On The Practical Design Method Of Flexural Performance Of RC Bridge Strengthened With Prestressed CFRP Plate

With the booming of economic construction, the transportation requirements of our country has been enhancing. While many highway bridges and railway bridges are being constructed, mounts of old bridges couldn’t meet the requirements and limits of modern transportation because of being out of repair for a long time, hence, it increases the burden of bridge maintenance and reinforcement. Thus, it is necessary to develop a new bridge reinforcing technique with good reinforcement effect, low-cost, and convenient installation. The prestressed carbon fiber plate reinforcement is a new reinforcing technique in recent years, it can not only improve bearing capacity of reinforcing structure,decrease the structure deformation,enhance strength and stiffness of structure, but also reach full potential of expressing the characteristic of carbon fiber plate which has high tensile strength. It also has prominent reinforcement effect with excellent durability, and is easy to construct.Many domestic and overseas scholars have done a plenty of research about the concrete girder bridge reinforced by prestressed CFRP plate, and have much research data. But the design theories and design principles of RC beam strengthened with prestressed CFRP plate are still lacking. Both the corresponding practical design forum of prestressed carbon fiber plate reinforcement technique and method of reinforcing design with RC beam strengthened with prestressed CFRP plate are scarce.Aiming at the lack of research production, the works of this paper are as following:First of all, this paper has collected the domestic and overseas experimental data about reinforced concrete bridge strengthened with prestressed CFRP plate, and conducted finite element simulation of reinforced concrete bridge strengthened with prestressed CFRP plate. Based on analyzing factor that would influence the effect of reinforcing, this text has found key influencing factors: the ratio of the tensile steel bar of original beam, the strength of concrete, the dosage of carbon fiber plate, the level of prestressing force, etc. With the basing of numerical simulation, the factor analysis of the RC beam strengthened with prestressed CFRP plate is completed.Second, in consideration of domestic and international experimental beam data and the results of numerical simulated factor analysis, this text has analyzed the design theory about bending bearing capacity of RC beam strengthened with prestressed CFRP plate. The failure mode of reinforced concrete bridge strengthened with prestressed CFRP plate is analyzed in this thesis, and the corresponding forum of bending bearing capacity is also constructed. This text has deduced the forum of CFRP plate strain increment under live loading, and obtained experimental forum of prestressed CFRP plate strain under ultimate condition by utilizing existing data to fit calculation. A calculation method was proposed for the stress increment under live loads with the parameter of comprehensive reinforcement index Combining the analysis of forcing process of concrete bridge strengthened with prestressed CFRP plate and the stiffness changes, this paper has deduced the forum of deformation.Finally, based on theory analysis and counting process of forum, this thesis has summarized practical design method of RC beam strengthened with prestressed CFRP plate, and given out basic process of reinforcing design as well as bearing capacity check calculation of RC beam strengthened with prestressed CFRP plate. Furthermore, the practical design method has been applied to reinforcing designing example of the real bridge, and verified the applicability and availability of practical design method of RC beam strengthened with prestressed CFRP plate.