Construction Monitoring Technology Of Pushing And Dragging Of Long-unit And Large-span Arch-shaped Steel Truss On High-speed Railway

Arched steel girder bridge is a new type of bridge structure developed on the basis of ordinary steel girder bridge and arch bridge,which has the advantages of self-weight weight,high strength and high stiffness,and has been gradually applied to the construction of high-speed railway bridge.When the large-span long-span arched steel girder bridge is constructed by the top-push-and-drag method,due to the continuous transformation of the structure system,the force and deformation of different conditions vary,so the study of this type of bridge in the process of top-pushing and dragging construction of the force and deformation change law,to ensure the construction safety of the structure and the bridge state after the bridge plays an important role.In this paper,with the Beijing-Zhang high-speed railway official hall reservoir special bridge as the engineering background,carried out 8 x 108 m large cross long arched steel girder bridge top push and drag construction monitoring technology research,the main results of the thesis are as follows:(1)Combined with the characteristics of the bridge structure and the actual situation of the project,from the numerous construction methods of the steel girder bridge,three kinds of construction methods are more in line with the Beijing-Zhang high-speed railway official hall reservoir bridge construction method,and from the supporting facilities,auxiliary tools,rod transport,environmental impact,economy,implementation difficulty and construction efficiency,etc.to compare and analyze the three construction methods,and finally determine the use of single-sided non-sectional top-pull technology for bridge construction,and finally for the top-to-bottom construction process.(2)A finite element model of large-span long-span arched steel girder bridge and considering the construction phase was established,and the strength,stiffness and stability analysis were carried out on the whole process of pushing and dragging the 8 x 108 m long-span long-span arched steel girder bridge.The whole bridge structure is relatively strong in the base of the guide beam and the main oblique rod during the construction process,while the deformation of the front end of the guide beam and the main girder span is relatively large,but the strain and deformation extreme values in the construction phase are less than the permissible limit.When the end of the structure is in the maximum cantilever state,the steel girder tail maximum suspension,the guide beam and the structure tail canbeak at the same time and the structure in the middle of the maximum span of the three lower states are most prone to structural instability,but in all states the structural stability coefficient is higher,to meet the safety needs of the construction work process.(3)Using the combination method of theoretical analysis and site monitoring,we carry out the research on the monitoring technology of the construction of the bridge's top push and pull,put forward the contents of measuring point arrangement and stress and deformation monitoring,developed the data analysis and processing method,and made an in-depth comparative analysis of the numerical simulation analysis results and the on-site measured values to ensure that the structural stress,deformation and so on meet the requirements of the specifications during the construction process.