Research On Spatial Alignment Of Long And Large Bridge Section

In recent years,with the continuous deepening of the construction of our national railway industry,the long and large bridge has gradually become an important part of our national railway network.Especially on high-speed railways,in order to meet the requirements of line smoothness and stability,ensure the safety and comfort of passengers,and reduce the impact of the railway on the existing environment along the line,dozens of kilometers of viaducts are often built.However,in the professional field of line selection,there is still a huge gap in the research of long and large bridge spatial alignment,and there is a lack of systematic research on the alignment of horizontal and vertical sections.Based on the research of this paper,a preliminary system is formed for the spatial alignment law of long bridges.At the same time,for long-span bridges,a longitudinal section design method that adapts to the longitudinal deformation of the bridge is proposed,which can play a certain role in the future longitudinal section design of long bridges.guiding role.The research contents and main conclusions of this paper are as follows:(1)The paper classifies the environment of long and large railway bridges in our country by literature method,and classifies the environment of long and large railway bridges into five categories,through the expert investigation and consultation,29 environmental factors were extracted,and the concept and basic situation were described.(2)For the long bridges in five environments,the importance of environmental influence factors was evaluated respectively,and after supplementation by experts,obtained the route selection strategy of long and large railway bridges in different environments and the law of plane alignment adapting to the environment.(3)The paper sums up the linear composition of the longitudinal section design of long and large bridge and the factors considered in each part,and draws the conclusion that two factors should be considered in the linear design: the pre-camber and the initial longitudinal section,both of them consider the factors that affect the longitudinal profile of long bridges.(4)For continuous girder bridges,arch bridges,and cable-stayed bridges,the maximum deflection corresponding to bridges with different spans are analyzed from a large number of engineering examples and finite element models,and analyzed the mathematical relationship between span and deflection.And for the longitudinal section design considering the longitudinal deformation of railway bridges,suggestions for longitudinal section design and parameter suggestions are put forward for each bridge type.