Vibration and sound radiation of Rail Transit viaduct

The Train-Track-Bridge coupling vibration theory and Boundary Element Method were employed to establish a calculation method for the noise radiated by vibrating bridge. A simply supported concrete U-beam serviced in Chongqing Rail Transit Line 1 in China was selected as a case study. According to the analysis, the vibration of U-beam under moving train mainly located in the frequency range of not more than 250 Hz, which is appropriate to calculate with the Boundary Element Method. The bridge structure noise is low frequency noise. Due to the ground reflection of sound waves, the maximum sound pressure area beneath the bridge is the overlapping area of bridge radiation and ground reflection. With the increases of distance from the bridge centre line, the sound pressure level gradually decreases, which descends about 5 dB for each additional distance of 9 m.