Key Technologies In Construction Process Of Long Span Continuous Girder Bridge On Passenger Dedicated Line

With the rapid development of China’s passenger dedicated lines,bridges have been more widely used in railway construction.During the construction of the passenger dedicated line,a large-span continuous beam bridge was constructed to bridge obstacles such as buildings,valleys and rivers.Due to the high requirements of the smoothness and stability of the passenger dedicated line,the line and stress control of the continuous beam bridge must be more accurate during the construction of the continuous beam bridge on the passenger dedicated line.At present,continuous girder bridges are often constructed using the cantilever method.The construction method has many construction procedures,it is difficult to construct,and the system conversion is complicated.Therefore,there are some uncertain factors in the entire construction process that affect the line shape and stress of the main girder structure,and thus affect continuous Beam bridge strength,stiffness,stability.Therefore,it is very necessary to carry out a detailed study on the key technical problems that occur in the construction of long-span continuous girder bridges on passenger dedicated lines.This article takes the four-span continuous beam bridge of(80+2 × 120+80)m in Xi’an-Chengdu Passenger Dedicated Line as engineering background to study the key technical problems in the construction process of continuous beam bridge.The specific research content is as follows:1.For the characteristics of high degree of linear smoothness of long-span continuous beam bridges on passenger dedicated lines,Introduced the development of passenger dedicated lines and continuous beam bridges,Characteristics of Continuous Beam Bridge on Passenger Dedicated Line,Continuous beam bridge construction technology,Key Technical Problems in Continuous Beam Construction at Home and Abroad.2.Three types of temporary consolidation models were established using finite element software Midas Civil,and three kinds of temporary consolidation simulation methods were studied for internal forces and deformations.Through the theoretical values of the models and field measurements,a more reasonable method for the temporary consolidation simulation during the construction of the“T”structure was determined.3.The finite element software Midas Civil was used to establish the simulation model of the main beam structure construction process,the different closing sequences were studied.By comparing the cumulative displacement difference of the main beam structure during the construction phase,the displacement during the completion phase,and the stress of the upper and lower edges,and combining the conditions of the construction site,a more reasonable closing scheme was determined.4.The effect of the difference in the age of the cantilever on the stress and deformation of the continuous beam was simulated by the finite element software Midas Civil.When the construction of the maximum cantilever sections of the two side piers “T” is completed,the“T”-shaped cantilever section of the pier during construction,analysis of the Special Closing Order of the Delayed Construction of Cantilever Section of Middle Pier “ T ” Structure,comparing the displacement of the maximum cantilever segment,the state of the bridged state,and the stress of the upper and lower edges of the bridge in the original design closing order and special closing order,it is concluded that there is a large change in the displacement at both ends of the closing opening,a large change in the displacement at the completion phase and a small change in the lower and upper edges of the bridge.When the difference in the age of the cantilever is inevitable,the displacement of the main beam structure will change,and measures to control the deformation of the continuous beam in the construction process are proposed.5.Based on the finite element model,the sensitivity analysis of the structural design parameters in the construction process of the continuous girder bridge was carried out using the control variable method,and the parameters that had a greater impact on the main girder structure were studied in order to control it in the construction process.