Static And Dynamic Analysis Research On Four-Tracks Heavy-Load Railway Steel Truss Beam Cable-Stayed Bridge

With the accelerating pace of national high-speed rail network’s construction, cable-stayed bridges prove to be a reasonable choice to cross the river and valley. As a kind of flexible structure, how to satisfy heavy railway load to ensure the security and stability during operation phase turns to be an increasingly important research topic.Taking a domestic four-tracks high-speed railway heavy-load cable-stayed bridge as background, it is the first four-tracks large span wide truss railway cable-stayed bridge which adopts two main trusses interiorly. Static and dynamic analysis are carried out combined with the design, paper mainly researches on mechanical characteristics, structure’s stress and deformation conditions under static live load, natural vibration characteristics, seismic response and stability under static wind load and rail live load. The study includes the following aspects:(1) Based on calculation software Midas Civil 2012 a full-bridge three-dimensional finite element model composed of beam elements, cable elements and plate elements is established, calculating and analyzing stress and deformation during construction stages, taking the effect of shrinkage and creep factor into consideration;(2) Calculate and analyze the pylon, steel truss and cable’s stress status under live load, wind load, temperature load, foundation settlement and different load combinations during operational phase, puts forward advices to optimize the components’stress state.(3) The subspace iteration method is used to calculate the structure’s natural vibration characteristics, the response spectrum and time history method are applied to analyze the response of bridge under earthquake.(4) Elastic stability are calculated and analyzed during construction stages and the operational phase, the conclusions show that the stability of the bridge structure can meet the requirements.