Stability Analysis And Reliability Analysis Of High Pier And Long Span Continuous Rigid Frame Bridge During Construction Period

With the large-scale construction of highways bridges and other transportation facilities in western China,high-pier and large-span continuous rigid-frame bridges have been adopted on a large scale.And with the increase of the span of continuous rigid frame bridges and the height of bridge piers,the structural stability of the construction period has received more and more attention.The paper takes the high-pier and large-span continuous rigid-frame super large bridge in Luzhou,Sichuan Province as the engineering background,and analyzes the stability and reliability of the bridge during the construction period.The specific work of the article is as follows:1.The development of rigid-frame bridges at home and abroad was briefly introduced,and the research status of the stability of high-pier and long-span continuous rigid-frame bridges at home and abroad was reviewed.The history of the development of structural reliability was briefly described,and the differences in two types of stability problems?structural stability evaluation indexes and criteria and stability of safety factor were introduced.2.The finite element software was used to establish the calculation model of the extra large continuous rigid frame bridge,and the linear elastic stability safety coefficient of the highest bare pier stage,the maximum cantilever stage and the closing stage during the construction period was calculated,and the stability of the bridge during the construction period was met.In the largest cantilever stage,the value of the stability safety factor is the smallest,that is,the stability is the lowest.The influence of various influencing factors(concrete strength,concrete bulk density,pier wall thickness,etc.)on stability was analyzed,and factors that are more sensitive to the influence of stability were obtained.3.The geometric nonlinearity of the bridge structure is described.The basic principles?solving methods and convergence criteria of the geometric nonlinear analysis are introduced.The finite element software was used to analyze the geometric nonlinearity of the bridge during the maximum cantilever phase.The geometric nonlinearity of the bridge has a certain influence on the stability.4.The stability of the maximum cantilever stage of the bridge is analyzed,and the reliability analysis model and function are established.The response surface method is briefly introduced and the reliability index calculation process is described.Using MATLAB software,based on response surface method,the reliability index and failure probability of the structural stability safety factor in the maximum cantilever stage during construction are obtained.Finally,the parameter sensitivity analysis of the stability of the maximum cantilever stage is performed.It is concluded that the variability of the elastic modulus of the pier has the greatest influence on the reliability index,and the variability of the concrete bulk density has the second highest impact on the reliability index,while the influence of the variability of temporary load and wind load and basket load is negligible.