Finite element simulation prior to reconstruction of a steel railway bridge to reduce structure-born noise

As part of the reconstruction of a railway bridge across the river Danube, numerical simulations were carried out during the planning stages of the project in order to investigate factors which play an important role in the radiation of structure-borne noise. The parameter studies centred around two possible construction techniques for the new bridge: an orthotropic steel deck with ballasted track, versus a composite bridge with a pre-stressed concrete deck plate and an embedded rail system. The aim was to find the optimum solution in terms of structural vibration and thus reduce resonance effects which are perceived more strongly than for tracks at-grade, as the vibration of bridge components adds to the rolling noise. Seeing as rail tracks are increasingly built in densely populated areas, this problem has become a core issue during environmental impact assessments. The results acquired from the material and structural modelling described herein were successfully implemented in the Tulln railway bridge in Lower Austria, alongside other noise-reducing measures such as sound barriers and rail grinding.