Noise radiation from steel bridge structure-Old Årsta bridge Stockholm

The 1929 Old Årsta bridge of central Stockholm (Sweden), owned and operated by the Swedish Transport Administration, is a monumental structure of architectural value and infrastructural importance to the city. Following recent renovation work, an increase of train noise was observed. Hence, it was decided to mitigate the noise. A multi-step project was defined to this end. The present paper presents the findings of the pre-study, the purpose of which was to investigate the noise radiation from the bridge steel structure, and the partial contributions from deck, girders, wheel/rail contact etc.. This involved vibro-acoustic modelling by Statistical Energy Analysis, laboratory testing of various Constrained Layer Damping (CLD) configurations at different temperatures, as well as similar CLD tests on a mock-up, noise and vibration measurements on the actual bridge, and acoustical beamforming measurements.