Safety Analysis Of The Train Passing Through The Tower Of The Long-span Bridge In Cross Wind

In recent years, with the increase of the span of the long-span bridges, the width of the towers may be up to ten meters and even dozen ten meters along the direction of the span.When the long-span railway bridge is in the environment of the cross wind, the wind loads would be changed because of the block effect of the huge tower, as the train enters and exits the region of the tower. As a result, the dynamic responses of the train, the safety of trains and the comfort of passengers would be impacted by the mutation of the wind load. In addition, the bridge’s dynamic response would be affected by the change of the train’s response. So, the dynamic characteristics of the train when it passes through the area of pylon in the environment of the cross wind need to be studied and the influences of towers’wake effect on the dynamic responses of the train and bridge need to be explored.Based on the engineering background of Oujiang road-rail suspension bridge, the dynamic analysis model of the wind-vehicle-bridge system was established. And the method of rapid spectral analysis was used to simulate the wind. The buffeting wind loads on the bridge subsystem and steady-state wind loads were imposed to the vehicle subsystem to analyze the dynamic responses of the vehicle and bridge when the train enters and exits the region of the tower. This paper is consists of the following four parts:Firstly, the present research situation of the coupling vibration of vehicle-bridge system and the vibrations of long-span bridges caused by the wind and the action of wind on vehicles was reviewed. And the research necessity of the train passing through the region of the tower was explained.Secondly, the vehicle-bridge dynamic interaction model under wind loads was established and the vehicle equations of motion, the bridge equations of motion, and wind-vehicle-bridge equations of motion were obtained. And the wind loads imposed on the bridge and the train was described.Thirdly, the influences of the wake effect of the tower on the wind loads imposed on the train were described by theoretical analysis. The changes of the wind loads imposed on the body of the train were comprehensively analyzed under the cases of the width of the tower greater and less than the length of the train.Finally, based on the engineering background of Oujiang road-rail suspension bridge, the entire process of the train passing through the tower under the fluctuating wind was stimulated. Considering the relationship between the width of the tower and the length of the vehicle, the influences of wake effect of the towers on the vehicle and bridge’s dynamic responses were analyzed with different train speeds and different wind speeds.