PREDICTION AND SPATIAL DISTRIBUTION OF LOW-FREQUENCY NOISE RADIATED FROM THE MULTI-SPAN BRIDGE

A single-span bridge model was usually used in the bridge noise simulation in most of the existing literature, which ignores the noise radiated from adjacent spans. A prediction method is proposed to predict the multi-span bridge noise in this study. First, the vibrations of the multi-span bridge are calculated from the vehicle-track-bridge interaction analysis. Then, the modal acoustic transfer vectors (MATVs) of the multi-span bridge are obtained using the 2.5 dimensional (2.5D) boundary element method. Finally, the multi-span bridge noise can be derived combing the bridge vibration and the associated MATVs. The simulated sound pressures radiated from the U-shaped girder obtained from the multi-span bridge model and single-span model are compared with the measurements, and the research shows the multi-span bridge model should be used in the far field noise prediction. The investigation of the spatial distribution of the multi-span bridge noise shows the bridge noise almost distribute uniformly along the longitudinal direction. Thus, an arbitrary section perpendicular to the bridge can be chosen in the field test.