Assessing And Reinforceing Of Maintaining Of Old Arch Bridge

With the development of transportation,bridge,as a junction,play a more and more important role and has already become the vital nexus of economical development.Especially in the 70s when we built many arch bridges,these old bridges,under the effects of external physics and chemical factors,concrete construction may occur aging and cracking phenomenon,which will reduce bridge's strength,rigidity and stability.All these will influence normal use of structure and will lead Collapse if seriously.For these reasons,it is an urgent task to do safety profile and maintenauce about bridges.In this paper,based on detail analysis on bridge construture and correlation theory of mechanics,combining the actual bridge,we study the assessment and reinforcement of bridges.Within detail investigation of many existent bridges,under dynamic environment,technical conditions which are different from that of design conditions and also their using conditions are so different that lead to safety hazards. Select 15 more serious disease bridges to do technology evaluation.On the base of evaluation,Against the background of Nanhe Bridge,analyze the Disease,its reasions,bridges' conditionsand reinforcement technology.Results show that with an additional larger internal force caused by departure of arch axis and the line of dead load,could lead to large stress of main ring or cross-section.So in the future long-span arch bridge design we should include the effects of bias flexural momentAgainst the background of Nanhe Bridge,have the tests of static load and dynamic load for a real bridge,and then identify the role of a bridge structure under the load and the performance capability,offer useful conclusions,in order to provide a basis for bridg maintenance's decision-making.On the basis of the use of the existing research results,make reasonable analysis of all the structures of Nanhe Bridge,determine a model approximates to the facts.Detect and investigate the original structural materials,and then determine the elastic modulus reduction factor of concrete and initial internal force caused by shrinkage and creep.Use GQJS software to establish Nanhe finite element analysis model,compare internal forces before and after reinforcement,provide three reinforcing plan in connection with bridge defects,choose the best one through comparing and selecting process,and then offer a certain practical reference for other bridges.