Buffeting Time-Domain And Stability Analysis For Long-Span Steel Truss Cable-Stayed Bridge Of Combined Highway And Railway

With the rapidly development of economy after entered the21th century, strong transportation network became more and more important in our country, and at this right moment, combined highway and railway bridge emerged. Most of the combined highway and railway bridges built nowadays are Cable-stayed bridge or Suspension bridge with steel truss girder. Usually, this kind of bridge has a very long span, which is a little flexible itself, so that, the analysis of wind resistance property of the bridge is essential. Besides, the live load emerges on the bridge of combined highway and railway is huge and complex, therefore the stability analysis of this kind of bridge becomes so necessary as well.In this thesis, the time-domain buffeting analysis and stability analysis during using stage of one combined highway and railway cable-stayed bridge with steel truss girder are done, simple discussion and safety judgment are also in progress from the analysis results. The main works are as follows:1. Introducing the research situation of this kind of bridge in nowadays and the main content in the thesis.2. Combining with the characteristics of natural wind, the three-dimensional wind field is simplified into three separated one-dimensional wind field, the wind fields of main girder and bridge towers and piers are simulated by Harmony Superposition Method.3. The finite element model is built by finite element analysis software-ANSYS, and natural vibration properties of building and using stage of this bridge are acquired.4. The buffeting force is transformed into time domain form, and aerodynamic admittance function is introduced, the analysis result of which can be compared with the function without being introduced.5. The time domain analysis for buffeting of using and building stage is conducted, the response of which with and without aerodynamic admittance function is compared. And the factors that affect the buffeting response are also discussed.6. The stability analysis is conducted under some kinds of combined live load during using stage of the bridge, and the effect of lateral wind loads to the stability analysis is discussed as well.