Groundborne Railway Noise and Vibration in Buildings: Results of a Structural and Acoustic Parametric Study

Two parametric studies have been conducted in order to examine the influence of a number of building and room parameters on the groundborne noise and vibration levels in a room. The studies have each utilised a three-dimensional finite element (FE) approach, validated with site measurements. It was found that changing the floor thickness had a limited effect on floor vibration, whereas changing the floor area was found to be more important, due to shifting the floor mode frequencies. Structural damping was shown to be important, and should therefore be specified carefully when modelling building vibration. The FE model of a typical domestic room demonstrated that there is significant variation in groundborne noise at different room positions due to the influence of acoustic modes. It is therefore recommended that the low frequency procedure detailed in ISO 16283-1 be adopted for specifying and measuring groundborne noise in such rooms. The parametric study showed that the room reverberation time, room size and presence of furniture each have a moderate effect on the sound pressure level. Whilst the installation of wall linings was predicted to provide only a marginal improvement in sound pressure level, this effect is dependent on the relative contributions of the wall, ceiling and floor surfaces. Results from the parametric studies are being used to inform semi-empirical prediction formulae for groundborne noise and vibration.