Shielding Effect of U-shaped Girder Bridge on Wheel-rail Noise

摘要

The predominant noise source of a train operating below 120 km/h is wheel-rail noise. Decades of outstanding research has demonstrated that wheel-rail noise can be substantially attenuated by using of noise barriers. Bridge engineers tend to design a through type bridge, for instance, U-shaped girder bridge, for railway lines passing through residual areas. The webs of the U-shaped girder function as low-rise noise barriers, which is believed to be able to reduce wheel-rail noise; whereas, mechanism of this shielding effect and its quantitative analysis remain unsolved. This paper aims to numerically determine its effectiveness. Two-dimensional models based on boundary element method (BEM) was built to perform the numerical simulations, in which detailed cross-sections of an U-shaped girder and a box-shaped girder as well as track structure were considered. The equivalent noise source of the wheel-rail noise was obtained from measured results. The quantitative analysis of the shielding effect was calculated based on the BEM models. Three parameters of a U-shaped girder, i.e., flange length, web height and web angle, were modified to investigate their influences. Some valuable results in theory and engineering were finally obtained.