Influence of Train Load Position on Sound Radiation Characteristics of Viaduct Box Bridge

In high-speed railway, the slab and the box bridge are the important noise-radiated components. Because the stiffness of the bridge is not well distributed along bridge longitudinal direction, when a train passes through the elevated bridge, the wheel load position has a certain influence on the box bridge structure's noise emission. In order to probe the influence of wheel load position on structure acoustic radiation characteristics of the box bridge, modal acoustic transfer vector method (MATV) is used. The results show that the shell element does better than solid element in simulation of bridge noise emission. The method of modal acoustic transfer vector can better combine with box bridge modal, so the bridge's own sound characteristics can more accurately be reflected. The acoustic field under the bridge changes randomly with different frequency. With the distance increase 15m in the range of 15~45m horizontally, the noise radiation pressure level of the box bridge averagely decreases 8dB; but then in the range of 45~50m, it becomes high. For a single box bridge, the sound pressure of double lines is higher 6dB than that of single one at 0~280Hz. In different loading modes, the noise emission caused by the box bridge is very different.