Rolling noise and structure-borne noise radiating from the bridge are two major sources of noise in light rapid transit (LRT) bridges. To control the noise radiation from LRT bridges, an efficient numerical method for noise prediction is needed. In this study, a combined three-dimensional dynamic model and 2.5-dimensional acoustic model were used to investigate noise reduction in a rail and in a U-shaped girder bridge. The effects of three noise mitigation measures on noise control were then compared: installation of a noise barrier, use of a rail pad with a lower stiffness, and use of a floating ladder track. The corresponding noise reduction was investigated using the numerical method. A field test was conducted to validate the noise reduction effects. It was found that the noise barrier was more effective in reducing the rail noise, and the soft rail pad is more effective to control the bridge noise. The floating ladder track can significantly reduce bridge vibration, but the excessive vibration of the ladder track itself became another major noise source. The findings should guide the selection of appropriate mitigation measures for noise reduction in LRT bridges.

桥梁发出的滚动噪声和结构噪声是轻快行道（LRT）桥梁的两个主要噪声源。为了控制LRT桥的噪声辐射，需要一种有效的数值预测方法来进行噪声预测。在这项研究中，使用组合的三维动态模型和2.5维声学模型来研究铁路和U形梁桥的降噪。然后比较了三种降噪措施对噪声控制的影响：安装隔音屏障，使用具有较低刚度的滑轨垫以及使用浮动梯形轨道。使用数值方法研究了相应的降噪。进行了现场测试以验证降噪效果。结果发现，隔音屏障在降低轨道噪音方面更为有效，软轨垫更有效地控制了桥梁的噪音。浮动的梯形轨道可以显着减少桥梁振动，但是梯形轨道本身的过度振动成为另一个主要的噪声源。研究结果应指导选择适当的缓解措施以减少轻轨桥梁的噪声。