Acoustic-Vibration Characteristics of Steel-Spring-Floating-Slab-Track on Urban Rail Transit Bridge

With the rapid development of urbanization in China and the continuous improvement of people's living standards, urban traffic congestion and people's travel efficiency have become urgent problems to be solved. Urban rail transit has many advantages, such as high capacity and efficiency, low energy consumption, fast and convenient, safety and comfort, etc., which has become the most effective measure to solve the above problems, and also an important way to realize the adjustment of urban spatial layout and balanced urban development. The main characteristic of urban rail transit development in China is that it starts late but develops rapidly. At present, urban rail transit lines had been built in many cities, among which the urban rail transit network in major cities has basically realized the whole coverage of urban areas. According to the construction mode, urban rail transit can be divided into three types which are underground line, ground line, and elevated line. The environmental vibration problem caused by underground line operation has been highly attention. The ground buildings' vibration in sensitive areas such as hospitals, museums, heritage buildings, scientific research institutes, and libraries is a hot research topic, but the vibration and noise in vehicle are often ignored. The noise on the ground line and the elevated line will have a great impact on the lives of the residents along the line. Together with the environmental vibration, both impacts will affect the lives of the surrounding residents. At present, the research on urban rail transit mainly focuses on the design and development of track damping and its related performance that the aim is reducing the environmental vibration. In addition, the research of bridge acoustic-vibration characteristics on elevated lines is often studied. However, when a train passes the elevated bridge that lay the track, the track will become the sound source by its vibration and the noise can be radiated as well. Combined with the acoustic radiation of the bridge, the whole acoustic radiation of the elevated line will be aggravated. At present, there are few research of the acoustic-vibration characteristics of the track structure on the bridge. Therefore, the steel-spring-floating-slab-track (SSFST) with good performance of vibration damping in China is taken as research object in the paper. The vehicle-SSFST-box girder bridge coupling dynamic model and the acoustic boundary element model of SSFST are established and adopt the numerical simulation method to detailed study the acoustic-vibration characteristics of SSFST on the bridge. The research results can provide theoretical foundation for the noise reduction design of SSFST.