There is a risk of local instability of the steel beams when using the installation process of steel beams first and then concrete slabs for the plate-truss composite deck steel truss continuous beam bridge.Taking the Hefei-Wuhan high speed railway Jinzhai Shihe Extra Large Bridge(72+3×132+72)m plate-truss composite deck steel truss continuous beam as the research object,this paper studied the local instability problem that exists when the ribbed steel bottom plate and concrete bottom plate in the compression zone are not fully combined during the construction process.A finite element method was used to establish a whole bridge structural model,simulate the influence of lifting beam at support point on the local stability of the steel bottom plate between the trusses,and conduct static analysis and linear buckling analysis on the construction stage of the lifting and falling beam at support point to obtain the stress state and local instability mode of the bridge during the lifting process.Optimization and comparative analysis of key structural parameters based on local instability,proposing optimization measures such as thickening the steel bottom plate between trusses,increasing the size of stiffeners,and reducing the spacing between lower crossbeams.The results show that increasing the thickness of the plate and the size of the stiffeners does not significantly improve the buckling stability of the truss bottom plate and is not economical.Reducing the spacing between the lower crossbeams can significantly improve the local stability of the steel bottom plate in the compression zone,with optimal economic efficiency.
plate-truss composite beamlifting and falling beam at support pointfinite element methodlocal stabilitybuckling analysis
维普
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