Sensitivity Analysis Of Typical Damage Of Sanguxian Viaduct

With the rapid development of highway building and the improvement of the material performance as well as construction technology in bridge,the Long-span pre-stressed concrete continuous box-girder bridge(continuous beam,continuous Rigid,Rigid-Continuous Composite Bridge) has been widely used because of its excellent performance and easy maintenance features.But because of limitation of understanding large-span continuous box-girder bridge,and with the growth of operating period,some diseases such as structural cracking,cross-excessive deflection appeared to some extent in a number of large. span continuous girder bridge,which damage the appearance of the bridge,and influence the bridge structure safety and durability.So the cracking and cross-excessive deflection of bridge become an urgent subject which restricts the development of the large-span continuous box-girder bridges.The article depends on the topic "the cause of the using pre-stressed concrete continuous box-girder bridge's research in the cold area",takes structural cracking cross-excessive deflection appeared to Sanguxian viaduct(Rigid-Continuous Composite Bridge) as the research background,unifies the bridge examination,and carries on the sensitive analysis to the influencing factors of its diseases.The main works are as follows:To begin with,typical diseases(Cross-deflection,roof,floor,and web Plate cracks etc.)of the Sanguxian viaduct(Rigid-Continuous Composite Bridge) are described,and on the basis of reference materials and stress characteristics,the sensitivity factors of diseases are identified.Then according to the structural characteristics of Sanguxian viaduct,choose the appropriate structure theory,and use MADIS/Civil Dr.Bridge3.1 to create the analysis model of Sanguxian viaduct for studying internal forces and deformation of the Sanguxian viaduct.What's more,the analysis of sensitivity factor of Sanguxian viaduct disease is processed by the method of simulation,which mainly includes:sensitivity analysis of the box-girder cracking and the cross- deflection.The main reasons for Sanguxian viaduct disease are developed through sensitivity analysis.Finally,based on the sensitivity analysis,create the injury model of the structure,and then explore the strengthening technical measures for the Sanguxian viaduct.Through the stuctrue analysis,although the structure original design satisfies the code requirement,but the partial cross sections' safety margin is low.The congenital safety margin and the stress fluctuations which caused by various sensitive parameters combine to the antipulls limit value of the concretes,and create the structure dehiscence.Each influencing factor comparatively speaking,the longitudinal loss of pre-stressed and the overload are big to the ledger wall dehiscence;the vertical pre-stressed is big to the web plate dehiscence;the structure dehiscence causes the dropping of various sections' rigidity.The reduction of the structure's rigidity is the primary cause of the cross down-warping oversized.The validity of the longitudinal pre-stressed and the overload is also the important cause.