Study On Construction Control Optimization And Monitoring Evaluation Of Long Span Continuous Girder Bridge Of Railway

With the continuous increase of bridge span,the construction difficulty gradually increased,and many new problems occurred during the construction and operation of the bridge.Through field monitoring and data analysis method,the bridge monitoring work can get the actual stress and deformation at each construction stage,find out the deviation between actual state and ideal design state,and rectify the deviation in time to ensure the smooth forming of the bridge.However,most bridge monitoring work lacks comprehensive evaluation of construction monitoring effect after completion of bridge.Therefore,this article wants to establish a set of evaluation system for bridge construction monitoring,through the analysis and evaluation of this bridge construction monitoring work,summarizes the innovation and deficiency,accumulate valuable experience for construction monitoring and control of the same type of bridge.Based on Chaobai river extra-large bridge(60+4×106+60m)long-span prestressed concrete continuous girder bridge as engineering background,by calculating the weight index and degree of success,this paper compared the site construction monitoring data and finite element model analysis data,carried out monitoring evaluation from three aspects such as bridge linear,girder stress and construction period,used curve correlation analysis and relevance method to calculate the grading index and evaluate the monitoring results.The main research work is as follows:(1)Using Midas/civil software to establish bridge finite element model,considering the prestressing effect,creep and shrinkage effect of concrete and actual boundary conditions of the bridge,calculating the theoretical prestressing camber,deflection and stress of each construction stage,preliminary studying the stress distribution and linear variation law of the large span prestressed concrete continuous girder bridge.(2)During the construction period of a long-span continuous girder bridge,through embedding strain gauge and observing beam deformation,this paper monitored the linearity and stress of the bridge on every structure stage,preliminary studied stress distribution law and linear variation law of the bridge in actual construction.(3)On the basis of the model optimization,the effect of the closure sequence of the long span continuous beam bridge on the stress and the alignment of the main beam is analyzed,and the optimization scheme which is different from the design proposal but the internal force satisfies the relevant specifications is put forward,and the bridge stress and the cumulative displacement of the bridge are further contrasted.(4)The post-monitoring evaluation system for railway long-span continuous girder bridge is established.With the main beam stress,beam alignment and construction duration as the main evaluation index,the correlation degree analysis method and the success degree method are applied to the monitoring and post-evaluation of the actual project.At the same time,it provides the necessary technical support for the construction monitoring and effect evaluation of the railway long span continuous girder bridge in the future.