Navigating Underground Assets at 5 Strand

5 Strand is being redeveloped into a 14-storey, 690-key hotel for client Whitbread, on a highly constrained central London site near Trafalgar Square, above a complex network of operational and disused London Underground infrastructure.

Elliott Wood’s structural strategy enables the significantly enlarged hotel scheme while retaining the existing basement and reusing most of the substantial raft foundation that previously supported the nine-storey reinforced concrete frame.

Using archive information and targeted opening-up works, Elliott Wood verified the reinforcement arrangements and behaviour of the retained raft foundation. Post-tensioned floor slabs are also being used to achieve efficient structural depths while limiting additional loads on the foundations.

This approach reduces demolition, material use and embodied carbon while allowing additional floors to be accommodated above the retained structure.

Numerous London Underground and TfL assets sit beneath the site, including disused Underground tunnels, a pedestrian concourse and a highly sensitive escalator tunnel. Securing TfL approval was therefore key to the application.

Detailed ground movement analysis undertaken with GCG and TfL demonstrated that predicted tunnel movements and lining stresses would remain within acceptable limits.

The structural strategy brings together retention, detailed investigation and analysis to support a substantially enlarged hotel scheme above some of the site’s most sensitive existing infrastructure.