Study On Scheme Comparison And Optimization Of Concrete Curved Box Girder Bridges Reinforcement

With the development of transportation in our country, existing bridges bears more and more traffic, especially the concrete bridges taking on diseases and damage of different degree. It is not reasonable and realistic to tear down and rebuild the damaged bridges. So it is of great significance to carry out the work of old bridge reinforcement deeply.This paper first reviews the old bridge strengthening research status at home and abroad and introduces the old the common deterioration problems of concrete bridge and its cause. Moreover, the common reinforcement methods and calculation principle are summarized. Secondly, combined with load test results before and after reinforcement of a fire damaged bridge to verify the feasibility of finite element analysis method. Finally, using finite element method, the pasted different thickness steel plate, different layers of carbon fiber sheet(CFS) on properties of the structure stress influence are analyzed on the basis of the selected a curved box girder bridge as reinforcement object.The study finds that, pasting steel plate or CFRP on box girder plate can significantly improve cross section bending resistance, and are more obvious with the limitation on crack effect. But that method is weak for the girder down warping inhibitory effect. Pasting steel plate on box girder web can substantially increase the shear bearing capacity, and the effect is more obvious. It is more reasonable pasting 8 mm thick steel plate or 1 layer of carbon fiber sheet(CFS) on bottom for the researched bridge in the established reinforcement target, and it is more economy choosing web 45 oblique pasting 8 mm thick steel plate.In this paper, combining with engineering examples and using the simplified calculation of finite element method, the different materials on the properties of stress influence on the curved box girder bridge are analyzed, and the optimum amount of materials under the target of the security reserve are analyzed which have a certain reference significance on the old bridge reinforcement engineering practice.