Noise-radiation analysis of box-shaped rail bridges considering multi-span effects

[[abstract]]Low-frequency structure-borne noise radiation from train-induced vibration of railway bridges is of concern to assess environmental impacts induced by urban metro system. To carry out the bridge-radiated noise analysis in assessing environmental impacts, the bridge vibration is regarded as an acoustic source of noise radiation so that the finite element (FE) bridge model combined with the acoustic boundary element (BE) method of spatial noise radiation is adopted in performing acoustical computations. For verification, an in-situ experimental noise measurement of rail box-shaped bridge on the selected metro line of Nanchang Metro is used to evaluate the feasibility of the present hybrid FE-BE approach. In addition, the method of panel acoustic contribution analysis is proposed to assess the noise levels radiated from a single/multi-span box-shaped bridges, respectively. With the present investigations, the multi-span bridges may result in larger structure-borne radiated sound pressure levels at far-fields than a single-span. Such a multi-span effect on bridge-radiated noise should be accounted for environmental noise evaluation along urban metro lines.[[notice]]補正完