Abstract：A 3-D rail-sleeper-ballast-beam FE model is established for the Sesia Bridge in Italy. The natural vibration characteristics of the bridge are analyzed by numerical study and field measurements. The coupled equations of motion are deduced for the vehicle-bridge system by assuming that the wheel-track interaction obeys the wheel-track corresponding assumption both in lateral and vertical directions. Taking the track irregularity samples based on German low disturb track spectra as excitation, the dynamic responses of the Sesia Bridge and the Italian high-speed ETR500Y train vehicles on the bridge are analyzed. The resonant train speeds are discussed and the running safety and stability of the train vehicles are evaluated. Some results are compared with the measured ones and a good agreement is found, thus the efficiency and validity of the established bridge model and proposed method are verified. Numerical results show that the Sesia Bridge is very stiff: as the train runs at the speed of 288km/h, the ratio of dynamic deflection to bridge span is only 1/17510. The vertical displacement of the bridge appears a peak value at the train speed of 340 km/h, indicating that bridge resonance may occur. The dynamic indices of the vehicle on the bridge are small, thus can well satisfy the high-speed train passage.
2013, Vol. 32 
