STUDY ON THE VIBRATION-ISOLATION EFFECTS OF ELASTIC BEARINGS ON TRAIN-INDUCED VIBRATION OF RAILWAY BRIDGE

To explore the effect of elastic bearings on vibration of the pier induced by a train running through at high speeds, spring-damper elements with 12 degrees of freedom were established to simulate bearings, which were then added to a train-track-bridge coupled vibration model. A typical simply-supported box-girder bridge with a span of 32 m was studied. Based on the train-track-bridge-bearing coupled vibration model with bearing elements, numerical simulation was carried out. The results show that the wheel unloading rate and the vertical acceleration of the vehicle are only marginally influenced by the stiffness of bearings. With the stiffness of bearings decreasing, the static component of the response of the bridge increases gradually, while the dynamic component decreases initially and then increases. For elastic bearings, the vibration attenuation in the whole frequency range is mainly determined by the vibration absorption effects in the dominant frequency band at 20Hz~80Hz. Because the natural frequency of the elastic bearings system is within the frequency band at 10Hz~20Hz, vibration in the intermediate and high frequency bands can be absorbed, while the vibration of its natural frequency band can be amplified. Therefore the elastic bearings can have prominent vibration isolation performance in the middle and high frequency bands.