Study On Technology Of Construction Monitoring Of Cross River Continuous Girder Bridge Of Rail Transportation

Rail transportation will become the development direction of city public transportation,with its advantages of low carbon environmental protection,high speed,punctuality,safety and comfort,and large passenger capacity.The prestressed concrete continuous girder bridge with its unique advantages,is widely used in highway bridge,railway bridge,city overpass and rail transit.The prestressed concrete continuous beam bridge cantilever casting method is widely used because of its unique construction characteristics.However,the hanging basket cantilever construction process is complicated,and it needs to undergo the process of system transformation.In the construction process of the uncertain factors will have a great impact on the stress state and alignment on the bridge.If it is not controlled,it may cause difficulties in closing the bridge and may even cause the bridge to collapse during the construction process.So,in order to ensure the bridge construction quality and safety,the bridge construction control is an important part of the indispensable.In this paper,rail transit across the continuous girder bridge of Qingpai river as the research background,the hanging basket cantilever construction process for construction monitoring technology research.The main research contents are as follows:(1)To row across the finite element simulation analysis of construction process of the continuous girder bridge of Qingpai river,according to the actual construction of the bridge site of bridge material properties,construction error and boundary constraint conditions to modify calculating model.(2)The structure of the whole process of the bridge construction stage deformation,strain monitoring,with the implementation of the adaptive control method to guide the bridge.(3)Through numerical simulation and measured data of comparative analysis,control the model level and key section stress.The main research conclusions are as follows:(1)The implementation of bridge construction monitoring provides a comprehensive and timely monitoring and control work for the hanging basket cantilever construction process of the continuous girder bridge of Qingpai river.It provides a strong guarantee for the construction quality,the progress of the project and the safety of the structure.In the process of each cantilever beams,are carried out a rigorous inspection and provide accurate field measurement data,founding problems in a timely manner.It provides strong support for the smooth construction of the bridge.(2)In the cantilever construction process and the bridge stage,the measured stress variation of the roof and the bottom of the main girder has no obvious mutation.The change trend of the main girder is basically the same as the theoretical calculation result,and the control precision satisfies the requirements of the admission control deviation ± 1.5MPa.Structure of the final measured force is within the allowable range of the prestressed concrete bridge,and structural stress monitoring performance is good.The deformation state of the structure in the construction process and the bridge stage is basically the same as the theoretical calculation and design and monitoring requirements,including the deflection control,the structural joint clearance accuracy and the bridge linear index,and the structural deformation monitoring performance is good.(3)In the process of construction,the internal force and structural deformation of the main beam are well controlled.The whole construction process of the bridge is controlled,and the structure of various indicators is good.