Research On Construction Control Technology Of Walking Type Jacking Of Steel Tied Arch Bridge

Steel tied arch bridges are widely used in crossing urban main roads,urban rivers,expressways,railways and other projects because of their strong crossing ability,beautiful shape,practical durability and light weight.Because of the demand of river navigation and road traffic,it will affect the normal operation and cause the traffic inconvenience.In order to solve this problem,the step pushing method came into being.Walking type jacking method can be used to push the bridge to the corresponding position with three-way jack without affecting the navigation and traffic.It has the advantages of short construction period,high technical content and high degree of mechanized and automatic construction.In this paper,the construction mechanics and key construction monitoring technology in the process of step-by-step jacking are analyzed and studied based on the engineering background of Nanjing Yexiu second road bridge crossing Qinhuai River steel tied arch bridge.The main research contents and achievements of this paper are as follows:(1)Mechanical analysis and monitoring theory of the whole construction process.There is a big difference between the structural stress system and the use state in the construction process.Therefore,it is necessary to establish the mechanical analysis theory in the whole construction process.Iterative method,incremental method and hybrid method are used to consider the influence of nonlinear factors in the whole process of construction and increase the accuracy of simulation analysis.At the same time,combined with the method of forward analysis,reverse analysis and stress-free analysis,the construction process is simulated to determine the optimal construction scheme to ensure that the bridge meets the design requirements after forming.(2)Research on the key technology of step pushing construction of steel tied arch bridge.According to the characteristics of steel tied arch bridge,the jacking construction scheme isdetermined.Combined with the simulation analysis results of MIDAS civil on the construction process,the key performance indexes of jacking construction are studied.Considering the nonlinear factors such as the assembly error of bridge assembly stage and the uneven settlement of temporary buttress,the calculation model is modified.This paper studies the influence of different wind strut connection and suspender tension on the jacking construction and final alignment of the bridge.(3)Research on construction monitoring technology of walking type launching of steel tied arch bridge.Combined with the simulation analysis results of the whole construction process,the monitoring indicators of the whole construction process are determined.The intelligent monitoring system is used to monitor and forewarn the whole process of the fixed jacking construction of the bridge in real time.At the same time,the calculation model is constantly modified according to the monitoring results to ensure the accuracy of the model results.This paper studies the construction control technology of walking type jacking method of steel tied arch bridge,which has better application in the actual project,and has guiding significance for the follow-up research and engineering application.