Mechanism, annoyance and control of noises generated from modular expansion joint in highway bridges

本研究的目的是探讨公路桥梁模块化伸缩缝中车辆通过时产生的环境噪声的机理、烦恼及控制。研究结果总结如下：1。对模块化伸缩缝的噪声产生机理及控制进行了实验研究。当汽车从关节模型上碾过时，测量了关节模型的噪声和振动。结合节理模型的声学和动力特性测试，认为节理顶部的噪声可能是由密封橡胶元件形成的间隙内气压的突然变化引起的，底部的噪声可能是由中间梁振动的声辐射引起的。并对所提出的噪声控制措施的效果进行了实验研究。对非组合工字钢梁桥和组合式伸缩缝PC箱梁桥进行了现场噪声和振动测量。在每种情况下，当不同类型的车辆以不同的速度通过连接处时，在桥上和桥下的几个点测量噪声。阐明了噪声在现场传播的非平稳特性以及桥梁、车辆和节点类型对噪声传播的影响。通过对声压a滤波谱及其非平稳特性的研究，讨论了环境噪声问题的可能来源。通过室内心理声学实验对模块化接头现场实测噪声的干扰进行了研究，确定了干扰噪声成分。

The objective of this research is to investigate the mechanism, annoyance and control of environmental noises generated by vehicle passage through modular type expansion joint in highway bridges. The research results are summarized as follows.1. The mechanism and control of noise generation for modular expansion joints were investigated in experiments on a full-scale model of the joint. Noise and vibration of the joint model were measured when a car was running over the model. It was concluded, based on this measurement together with tests of the acoustic and dynamic characteristics of the joint model, that the noise from the top of the joint could be attributed to a sudden change in the air pressure in the gaps formed by the sealing rubber elements, and the noise from the bottom was probably caused by sound radiation from vibration of the middle beams. Effects of some proposed noise control measures were also investigated experimentally.2. Field measurements of noise and vibration were conducted in a non-composite I-shaped steel-girder bridge and in a PC box girder bridge with modular expansion joints. In each case, the noise was measured at several points above and below the bridge when different type of vehicles passed over the joint with different speeds. The non-stationary characteristics of noise propagation in the field and effects of bridge, vehicle, and joint types were clarified. Possible sources of environmental noise problem were also discussed by studying the A-filtered spectra of sound pressures and their non-stationary characteristics.3. The annoyance of field-measured noises of modular type joint was also investigated by psychoacoustic experiment in a laboratory in order to identify the annoying noise components.