Research On Monitoring And Construction Technology Of Cantilever Bridge In Hangzhou Bay Bridge Connection Project

In recent years,with the rapid development of China's bridge,the requirement for driving comfort is higher.Among bridges,prestressed concrete continuous bridge has been developed rapidly because of salient features of large structural rigidity,small deformation,less expansion joints,simple construction method,obvious force characteristics and smooth driving,and it plays an important role in bridge construction project.Prestressed concrete continuous girder bridges are usually constructed by cantilever casting method,and it is a complicated process that needs to overcome many factors during the construction process.If the construction method is not controlled properly,the actual state of the bridge structure will deviate from the expected state.Therefore,it is necessary to carry out construction monitoring on the bridge,comparing with the actual construction situation on the site basing on structural analysis,achieving the line shape and stress target required by the bridge designer eventually.This paper takes the construction of cantilever beam bridge of Hangzhou Bay wiring project as the research background to study the construction monitoring technology of the bridge.Firstly,the monitoring scheme suitable for the bridge is put forward on the basis of generalizing and summarizing the cantilever pouring construction monitoring theory.In the calculation of the box girder theoretical elevation,the calculation method of the vertical model elevation in the cantilever construction stage is established by considering the bridge structure mode,load variation and related influencing factors,and the calculated theoretical and measured values are compared and analyzed at the same time.The finite element calculation software Midas/Civil is used to model and analyze the cantilever bridge 7# block,the maximum cantilever stage and the bridge stage,and the calculation results are analyzed and studied.In the simulation analysis,the beam weight,prestress,bridge load,concrete shrinkage and creep,structural system transformation and boundary conditions are considered.Secondly,the hanging basket has different effects on the bridge in different bridge construction section.Based on the analysis of the structure and stress characteristics of the hanging basket,a suitable calculation model of planar equivalent rod structure is constructed,and the calculation results are compared and analyzed.In addition,the influence of hanging basket on cantilever bridge is analyzed by calculating the overturn resistance of the hanging basket structure.The modeling calculation can reflect the actual stress characteristics of the hanging basket structure,realizing the simple calculation,high efficiency and standardization of the hanging basket structure,and is beneficial to the deepening application of the prestressed concrete continuous beam cantilever construction software technology.Finally,a detailed theoretical analysis is made to the continuous beam cantilever construction in the mid-span closing stage.According to the study of the process flow of the bridge closing section and the calculation of temporary consolidation bearingcapacity when the mid-span hanging basket is removed,the impact on the bridge construction when removing the basket can be obtained through calculation,so as to correct the deviation generated during the construction process in time,ensuring the safety of the bridge structure during the construction process effectively and providing theoretical support for the smooth closure of the bridge.