| ABSTRACT:As a special type of bridge, railway rush-repair steel truss girder bridge plays an important role in logistic support and emergency rush repair. The study on the dynamic interaction of rush-repair girder and train has great theory value and engineering significance for insuring the structure safety of rush-repair truss girders and the running safety of trains on the bridge.The development at home and abroad of the rush-repair girder is introduced and the basic research methods on dynamic response of the vehicle-bridge system are introduced in this paper. A 3-D interaction model of a Type-87 railway rush-repair steel truss girder with running trains is established, which consists of a train subsystem and a bridge subsystem. By applying the modal superposition technique to the bridge and using the track irregularities as the self-excitations of the train-bridge system, the train-bridge-coupling system equilibrium is derived and the relevant computer program is developed.Taking the Type-87 through steel truss girder as the case study, the three-dimension finite element models are established and the natural vibration characteristics of the bridges are analysed. The whole histories of the train running on the bridge are simulated and the dynamic responses of the bridges and the running trains are caculated. Based on the analysis above, the influences of bridge span, train speed, track irregularity and formation of train on the responses of vechicles and bridges are analysed, and some useful conclusions are obtained.The running safety and stability of the train vehicles on the bridges are evaluated, based on which the train speed thresholds are proposed as a reference of design.
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