THE VIBRATION AND NOISE CHARACTERISTICS OF A STEEL VIADUCT IN AN URBAN AREA AND A PROPOSAL FOR VIBRAT ION AND NOISE CONTROL

The object of this study is to find measures for reducing the noise generated when heavy vehicles run across the expansion joints of a steel viaduct in one urban area. For this study, both the vibration acceleration of the viaduct and the radiated noise are measured. Some strong relations between radiated noise and the vibration of the viaduct of girder members at some frequencies are identified. Taking into account the characteristics of the vibration and radiated noise, and the conditions of the viaduct site, the use of magnetic constrained-layer dampers are proposed for controlling the radiated noise. Some vibration tests and acoustic tests were performed on six kinds of magnetic constrained-layer dampers in order to find out the most effective way to reduce radiated noise. This paper describes the characteristics of the vibration at main gider members and those of the radiated noise. Magnetic constrained-layer dampers are proposed for reducing the radiated noise. It also takes into account the raffic noise around the viaduct.