Train-induced vibration and noise radiation of a prestressed concrete box-girder

The simply supported prestressed concrete (PC) box-girder is the most common type of bridge used in high-speed railway (HSR) and urban rail transit systems in China. Train-induced bridge vibration has been the subject of a number of investigations based on train-track-bridge coupling vibration theory, but the associated bridge-borne noise has received little attention. This paper presents a numerical simulation technique for high-frequency bridge vibration and the associated bridge-borne noise, which is then applied to a simply supported PC box-girder used in the Chengdu-Dujiangyan intercity railway. In an integrated finite element method-boundary element method (FEM-BEM) approach, the transient train-induced bridge vibration responses are first solved using a finite element method, and the steady responses of the sound pressure are then solved in the frequency domain using a boundary element method. The dynamic response of the bridge is taken to be the sound source, and the time-frequency transformation is performed by a Fast Fourier Transform (FFT). The predicted results for vibration and noise are in good agreement with data from field measurements. The results show that the dominant frequency range for both vibration and noise for the PC box-girder is 40-100 Hz and that there are significant tonal noise characteristics at 50 Hz. There are two noise “hot spots” beside the bridge, with complex directional properties. Finally, the effects of ground reflection and train speed on bridge-borne noise are discussed, based on the proposed acoustic computational procedure.