Dynamic Response of Long Span Cable-stayed Bridge subjected to Earthquake and Moving Train

For a long-span railway bridge with running-through train, the earthquake will cause extra deflection and vibration of the structure and give influences on runnability of the train,thus the dynamic interaction between train and bridge with earthquake effect will differ from that without earthquake effect.

In order to study this problem, an earthquake-vehicle-bridge dynamic interaction model of train and long span cable-stayed bridge under earthquake load is established in this paper. For this model, earthquake inertia force of both train and bridge are considered and the geometry nonlinear effects of bridge is included. Seismic responses of the train-bridge system are analyzed using dynamic timehistory analytic method. For cars and locomotives, a model of 27 degree of freedom with two stage suspension is used. By taking a cable-stayed bridge alternative of Tianxinzhou Yangtze-River Bridge with 504m main span and four railway lines as an example, dynamic response of this vehicle/bridge system under earthquake load are analyzed with two kind of train running through the bridge, one is a freight train of one locomotive plus 20 freight cars at 80km/h velocity,the other. is a passenger train of one locomotive plus 18 passenger cars at 200km/h velocity. And the seismic time-history curve is selected according to the principle which the earthquake will occur very possibly and the structure can normally be used under such an earthquake. Finally the dynamic performances of this bridge alternative under earthquake and moving train effects is evaluated.