NOISE AND VIBRATION FROM LUDGATE RAILWAY WORKS

This paper describes the investigation and measures for the control of possible noise and vibration from the new railway between St Pauls and Blackfriars on the Thameslink Line through central London. The study of noise and vibration was concentrated at a specific office block, where a possibly serious impact was anticipated and where users had expressed concern. It aimed to measure: (1) absolute floor vibration levels, due to existing trains and other environmental impacts; (2) attenuation with distance up the building; and (3) amplification due to floor response. The block was a reinforced concrete structure, with cast on-site concrete floors and raised office flooring. The new railway was constructed in a concrete box at ground level, so that there was unlikely to be an airborne noise problem. A maximum of 300mm concrete was specified for the box construction, and it was decided to use all-welded rails. It was predicted that low-frequency vibration from the new trains was unlikely to be perceptible, but resilient under-sleeper pads were placed along the track near the office block, to minimise structure-borne noise. The railway has now been operational for some time, with no adverse comments from occupants of the block. For the covering abstract see IRRD 867830.