Analysis Of Train Running Performance And Stiffness Influence Parameters Research Of Long-span Multi-tower Suspension Bridge

With the development of railway transportation, long-span multi-tower suspension bridge has become a hot point. To cross the wide water areas, the multi-tower suspension bridge was especially recommended by the bridge engineers. The vehicle-bridge coupled vibration problem under the impact of moving load is more prominent for the long-span bridge structure is relatively flexible, thus the stiffness requirement of such bridge structure is also increasing. In order to meet the safety of the train and the comfort requirements of passengers, it is necessary to do some analysis and research about the dynamic response of vehicle and multi-tower suspension bridge coupled system. The determination of the stiffness parameters is an important part of long-span suspension bridge design. The change of the major stiffness parameters has an important impact on the overall structure dynamic characteristics and the train running performance. At present, standard about the stiffness limit provisions is mostly for small and medium span bridges, which are not suitable for long-span bridges. Thus, it is a little difficult to guide the design of such long-span bridges for there are fewer engineering examples for reference.The work of this paper is one of the main content of the National Natural Science Foundation project of "wind tunnel test research of aerodynamic characteristics and anti-capsizing performance of high-speed railway vehicle-bridge system (51178471)". Combined with a three-tower rail-cum-road suspension bridge, the major work and results are as follows:(1) The finite element analysis model of OuJiang three-tower rail-cum-road suspension bridge is established, and its dynamic features were calculated and analyzed. The results show that the natural frequency of this bridge is low due to its low rigidity. The problem of lateral rigidity and vertical rigidity are both prominent. (2) The vehicle-bridge dynamic response and the train running performance are analyzed. The results show that both the lateral and vertical rigidity can meet the safety requirements of train running. All the dynamic responses of the vehicle and bridge can meet the smooth and comfort index of the vehicle and stiffness limit of the bridge when the CRH2train passed within the design speed.(3) A detailed research on the effects of stiffness parameters such as beam width, girder height, stiffness of main cable and pylon tower are made under multiple loading conditions. The discipline of the calculation results was summarized. The results show that increase of the width of girder can significantly increase lateral vibration frequency and reduce the transverse vibration response of the bridge. The increase of the height of girder, the stiffness of the middle tower and the stiffness of the main cable can significantly increase the vertical stiffness of the bridge and reduce the vertical vibration response of the bridge, which is beneficial to train running. The increase of these stiffness parameters can improve the train running performance, but the sensitivity will reduce when they increase to a certain extent.