A calculating method on roadside ground noise from the reverberation between the surface and the bridge bottom along a surface and viaduct combined road

摘要

Along a road that includes both ground-level sections and viaduct sections combined, the noise at homes on the ground will be impacted not only by the noise from vehicles moving on the surface, but also by the reverberation between the ground (sometimes far) below the viaduct bottom and the bridge bottom itself. In this situation, just installing noise barriers along the edges of the elevated sections will have very limited effectiveness because of the reverberation, which is not significantly reduced by the barriers. A theoretical method to calculate the roadside noise contributed by the reverberant noise field in an open space is suggested on the basis of virtual or image walls, traffic flow theory, and wave acoustics. Our purpose is to determine how the related parameters operate and affect the noise level on the ground beneath the bridge in order to optimize the noise control measures.