Tottenham Court Road Station
Just beside the aptly named Centre Point tower, Tottenham Court Road station has served an area as renowned for its theatres as for its offerings in the wider retail spectrum for over a hundred years. The arrival of the Crossrail 2 link has heralded major and complex extension works funded by London Underground.
Over 150,000 people currently use the station every day, and this is set to increase significantly with the arrival of Crossrail in 2018. Given these vast numbers, construction was carefully sequenced to minimise impact not only on the tube trains, which needed to run unimpeded throughout the process, but also on the busy interchange directly above the site. Works include expansion of the existing ticket hall and a new entrance to the station from Oxford Street with an 8-10 storey office building bearing onto this.
For the 55 m extension of the ticket hall, we used 4D modelling to inform our propping design, which would support the underground box and its 840 bored piles while excavation took place. We also had to replace a section of the roof, removing around 1.5 m of overburden before lifting out the existing structure. Since the removal of load would result in heave due to a decrease in pressure on the remaining clay, detailed calculations and monitoring of the ground movement was required.
Using 3D modelling to study the effects on its surroundings, we also overcame complexities to design a foundation solution for the new station entrance. Due to the existing network of tunnels and services, a concrete raft was specified, founded at several different levels; we connected basement and ground structures using reinforced concrete shear walls. A single column in the entrance area supports transfer structures under the superstructure of the office building above.
Extension of this central London station, heralding the arrival of Crossrail 2
Hawkins \ Brown
£ 500 million