Structural Analysis Of Long-span Double-deck And Four-line Railway Cable-stayed Bridge With Steel Truss And Optimization On Its Transverse Restraint System

In this thesis,the long-span double-deck and four-line railway steel truss girder cable-stayed bridge is taken as the engineering background,and the finite element model of the whole bridge is established by using the finite element software MIDAS CIVIL.The static and dynamic analysis of the bridge is carried out in detail,and the transverse restraint system of the bridge is studied and optimized in order to provide reference for related design.Firstly,the development and characteristics of steel truss girder cable-stayed bridge are introduced,and the research status of transverse restraint system of cable-stayed bridge are summarized.Aiming at the design scheme of(62.5+125+425+175+75)m double-deck and four-line railway steel truss girder cable-stayed bridge,the simulation methods of each component are described in detail,and the finite element model of the whole bridge based on beam element is established.In the aspect of static analysis,firstly,according to the construction steps,the calculation conditions of construction stages are divided,and the stress and deformation of main components in each construction stage are analyzed and calculated.Then the stress and deformation of the bridge under dead load,moving load,temperature load,train braking force,lateral rolling force and wind load are analyzed.In the aspect of dynamic analysis,the natural vibration characteristics of the bridge are calculated,and the seismic response of the structure is calculated by response spectrum method and time history analysis method respectively.After that,the transverse restraint system of cable-stayed bridge is explored and analyzed.According to the lateral restraint modes between the main girder and pier of the bridge,the static effect and dynamic responses of cable-stayed bridge under full restraint system,lateral sliding system,abutment lateral restraint system only and auxiliary pier lateral restraint system are discussed respectively,and the reasonable lateral restraint system of the bridge is selected by comparing the calculation results.Finally,the scheme is optimized on this basis,and the fluid viscous dampers are used in the transverse restraint system.The damping parameters are optimized through nonlinear time history analysis,and a set of reasonable damping parameters suitable for the bridge are determined.