Integral Joint Fatigue Analysis Of Long-span Railway Steel Truss Bridges Based On Coupling Vibration Of Vehicle-Bridge Systems

Higher requirement on train run-ability was put forward with the development of high-speed railway, thus more attention was paid on the vehicle-bridge coupling vibration. Although the application of long span steel bridge in the high-speed railway is gradually increasing, along with the fatigue damage phenomenon appears in the orthotropic bridge deck and welding integral node in succession, the fatigue performance of railway steel bridges was taken seriously by more and more scholars, fatigue has become an important research topic in the field of steel bridge. In this study, two research topics of railway bridges were linked to present a method which can do fatigue research base on analysis for vehicle-bridge coupling vibration. What’s more, relative influence factors for this method were explored.First of all, the full bridge model was established based on finite element software ANSYS, though the simulation of train loads cross the bridge under static function, the moment envelope diagram of80integral node in this bridge was calculated to determine fatigue wearing integral node.Then, vehicle-bridge coupling vibration analysis for CRH2was finished to get force time history at ends for each member bars located in the most dangerous integral node, which was accomplished by use of the finite element scientific software BANSYS.After that, local finite element model of integral node was established, by loading the force time history calculated through vehicle-bridge coupling vibration analysis on local model, stress time history on checking point was calculated by transient analysis in finite element software ANSYS. Furthermore, the stress spectrum on checking point was obtained and the maximum degree of damage was calculated according to Miner linear cumulative damage law.At last, vehicle-bridge coupling vibration was analyzed under different loading mode, different train lengths and different track irregularity, at the same time, the maximum degree of damage for the structure was computed under the corresponding condition. In this way, reliability of the method proposed in this article was proved, what’s more, influence factors which should be taken into consideration when do fatigue study basis on vehicle-bridge coupling vibration analysis were explored.