Evaluating bridge-borne noise contribution degree for a railway steel–concrete composite box girder

A train running across a bridge usually produces higher noise than on the ground. This increase in noise varies considerably from one bridge to another, but the noise contribution of different bridges is unclear. A hybrid finite element– boundary element–statistical energy analysis method is used to investigate the vibroacoustic characteristics of a steel–concrete composite (SCC) bridge induced by running trains. The numerical procedure is verified by using a scaled SCC bridge measured in the laboratory. The mechanism of vibration transmission and vibroacoustic comparisons between a 40-m span SCC bridge and a traditional all-concrete bridge are investigated, and the results show that higher vibration levels (12–20 dBA for different components) and sound levels (12 dBA on average) arise with the former. At a train speed of 300 km/h, the structural noise contribution of the SCC bridge to the total noise emission from the train pass-by is 67% in the near field. When the train speed reaches 385 km/h, the structural noise contribution can still reach 27%. The contribution of the deck and bottom plate to the structural noise was the highest, accounting for approximately 37%.