Coupled Vibration Analysis Of Train-Bridge System Of Elevated Light Railway

The train running on a bridge may creat the vibration of the bridge and vibration of the bridge may affect the running of the train, which will raise the problem of the coupled vibration of train-bridge system. With increasing of speed of trains and lightening and enlarging of bridge structures, the problem of the coupled vibration of the train-bridge system becomes more serious increasingly. Therefore, the studios on the causes to affect the couple vibration of the train-bridge system are paid more attention in the field engineering.In this thesis, the coupled vibration analysis of train-bridge system is emphsically studied considering the influence of the wheel hunting and irregularity of the track.First of all, the present status on the studies of the coupled vibration of train-bridge system is overviewed from the aspects of analytical models, exciting souces and solving methods, and the perspectives about the research in this field is indicated.A spatial model about the coupled vibration between the train and the bridge is built, and the equations of dynamic equilibrium of the coupled vibration of the train-bridge system are deduced through the compatibility conditions of displacement and under the excittaion of the wheel hunting and the irregularity of track.A MATLAB program for analyzing the coupled vibration of the train-bridge system is generated, and the dynamic responses of the elevated bridge are calculated under the excitation of the wheel hunting when the train is passing the bridge. The assessment on the safety of the bridge is carried out, and influence of the velocity of the train on the dynamic responses of the bridge is explored.Taking a four-span continuous rigid-framed prestressed concrete bridge in Tianjin light railway as the example, the dynamic responses of the bridge are investigated under the excitation of the wheel hunting and the irregularities of track. The results show that the dynamic responses of the bridge are increased but meet the indixes of safety. However, the irregularities of track should not be ignored in the coupled vibration analysis of the train-bridge system. Furtherly, the influence of the wavelength and wavedepth of the irregularities of track on the dynamic response of the bridge is analyzed, and the results show that the increasing of wavedepth may aggravate the dynamic responses of the bridge, but influence of the wavelength on the dynamic responses of the bridge is very complicated.