The Refined Study On The Stability And Local Mechanical Behavior For Three-truss Steel Girder In The Incremental Launching Construction

With the rapid development of economy,steel truss bridges develop rapidly in the bridge construction.Rigid suspension stiffened steel truss bridge is a new style,with some merits,such as beautiful configuration,big gravitational rigidity and good stabilization,etc.Taken the Ji'nan highway and railway bridge in the Yellow River as background,the paper based on the Rigid suspension stiffened steel truss bridge by launching construction regard as the research object,studied the stability and local mechanical behavior of the incremental launching construction on the basis of the numerical simulation of the whole construction process by Midas/Civil finite element software.The main works are follows:(1)Using the Midas/Civil to establish the structure computation model of the steel truss girder and scaffold,implement the stability analysis in the dangerous conditions during the construction process,the stable safety coefficient and unstable mode on dangerous conditions are obtained,meanwhile,caculate the stability coefficient of resisting capsizingof the main bridge.(2)Using the Midas/Fea to establish the solid model of the truss node,and analyze the Stress condition under the 3 kinds of unfavorable load conditions.(3)Through the establishment complete model of the bridge and scaffoldr,the paper analysed the situation of three truss construction of unequal height in the incremental launching construction.(4)Through the analysis of the main bridge model,the paper obtained the tensile force of each suspender by unknown load factor method.(5)Using the Abaqus to establish the slider,the steel strand and slide model to analyse the phenomenon of leapfrogging by simulating the process of movement of the slider.