Research On Static And Dynamic Performance Of Railway Long-span Hybrid Girder Single-tower Cable-stayed Bridge And Optimization Of Steel-concrete Composite Segment

Researches on cable-stayed bridges in my country are mostly on double-tower cable-stayed bridges,but there are few studies on single-tower cable-stayed bridges,so it is of great significance to study the long-span hybrid girder single-tower cable-stayed bridge.Concurrently,railway bridges have high structural design requirements due to its load characteristics,so it is necessary to study the mechanical properties of steel-concrete composite segment which is the key components of the bridge.In this thesis,a(32.7+50+93.7+260+38.2)m long-span railway cable-planes hybrid girder single-tower cable-stayed bridge is taken as the research object.Firstly,the development status of single-tower cable-stayed bridges and hybrid girder cable-stayed bridges are generalized,and the development status and structural characteristics of hybrid girder single-tower cable-stayed bridge are introduced.Then,a space model is established by MIDAS/CIVIL software based on beam elements,so the author uses the model to simulate the construction stage of the bridge where the deformation and stress of the structure are analyzed.In the meantime,the author uses the whole bridge model to analyze the deformation and stress of the structure under loads acting alone and load combinations in the operation stage.In addition,the author analyzes the self-vibration characteristics of the bridge considering the pile-soil-superstructure dynamic interaction,then analyzes the deformation and stress performances of the structure by both the response spectrum method and the time history method under load combinations and gets relevant conclusions after contrasting results of the two methods.Finally,the author introduces the classification of the structural forms of the steel-concrete composite segment.And a meticulous model of the steel-concrete composite segment is established by ABAQUS software based on solid elements and shell elements,then the author analyzes the stress of the joint and transition as well as stiffness variation under the most unfavorable load combination and optimize the location of the prestressed wire bundles for the problem of excessive tensile stress in the outer layer of part of the concrete inclined base plant.