Assessing re-radiated noise in a high-density urban office development in Central London

City of Westminster in Central London is a high-density urban area, hub for numerous government and commercial offices with major transport links. The proposed construction of a seven-storey office building is facing significant acoustic challenges as the site is located adjacent to a busy road and sits above three underground railway lines, being subjected to the risk of re-radiated noise due to train induced vibration. Additionally, the proposed use of cross-laminated timber (CLT) flooring presents challenges regarding vibration transmission. Vibration measurements have been undertaken within the site to assess compliance with perceptible vibration and re-radiated noise thresholds set by national and local standards. The results indicate that re-radiated noise is expected to cause significant disturbance to the building occupants. This study describes the methodology adopted to assess re-radiated noise using Kurzweil method and presents a basis for evaluating potential vibration mitigation strategies. Multiple vibration attenuation solutions have been assessed, including building isolation and localised box-in-box solutions for the most sensitive office spaces. All strategies have been collated and compared in terms of cost, attenuation performance and implementation risks to provide a comprehensive basis for decision making.