The use of dynamic dampers on the rail to reduce the noise of steel railway bridges

Even if all steel railway bridges are different, most of them produce more noise than ballasted track. If located in populated areas, steel bridges may generate annoyance for the population. Specific noise reduction solutions must be developed. A research programme has been started to deal with this problem. The vibroacoustic study of a reference steel bridge has been carried out over the whole frequency range from 5 to 5000 Hz using the finite element method (FEM) in the low-frequency range and statistical energy analysis (SEA) at higher frequencies. At higher frequencies, the rail appears to be the main acoustic source. This result is confirmed by an experimental characterization. The spatial decay rates of the rail vibration are very low, due to the rail fastening system. Then, noise reduction solutions dedicated to the rail are considered, especially dynamic dampers which have been specified. Two products have been selected and tested on the reference bridge. The experimental results are discussed.