Author: E. Newman-Sanders (Atkins), R. Smiley (Atkins)
2 July 2018
First published: 2 July 2018
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E. Newman-Sanders (Atkins), R. Smiley (Atkins)
A joint team from Crossrail Ltd, Atkins, Arup, Allies & Morrison, and Laing O'Rourke collaborated to develop the striking station design, creating a beacon for both the Elizabeth line and the local community. Faced with many constraints, a ‘kit of parts’ strategy was developed for Custom House’s construction, including prefabricated and standardised components.
This approach – where much of the station was built off site – minimised workon site, drove down programme times and costs, and reduced the impact on the local community. The approach also led to Custom House’s excellent health and safety record – one of the best of any Elizabeth line station to date.
The new Elizabeth line station at Tottenham Court Road, delivered by the Crossrail programme, has been an
exercise in interface management as well as a feat of engineering.
This paper describes the design carried out by the Arup Atkins Joint Venture (AAJV) under contract C134, principally of the Western Ticket Hall box. Nestled in Soho, this was developed within a dense urban grid and the constraints of a residential oversite development above.
The team worked closely with London Underground Ltd's engineers at the Eastern Entrance, which was delivered as part of London Underground’s own station upgrade works.
The tunnel for the eastbound Elizabeth line passes through the Western Ticket Hall box, which also provided construction access for the sprayed concrete-lined platform and concourse tunnels. Access dates to the site meant that there was insufficient time to complete construction of the box before the arrival of the tunnel boring machine (TBM). Consequently, the need to complete the excavation became critical and the team adopted a bottom-up construction sequence for one of the deepest open shafts ever excavated in central London. The box, formed of elements of diaphragm walls and raft, was constructed before the TBM arrived, and the remaining internal elements completed afterwards.
Canary Wharf was the first station on the Elizabeth line to be constructed, and the first to be let as a design-and-build contract, with developer Canary Wharf Group. Innovative design and construction techniques enabled the station box to be completed four months ahead of the development programme. Construction of the Crossrail Place retail and leisure oversite development (OSD) proceeded concurrently with that of station. The OSD included a number of features aimed at increasing future flexibility for the developer and tenants. A timber gridshell roof completes the development, partially covering a large roof garden that is open to the public. The OSD opened in May 2015, nearly four years ahead of the planned station opening.
Tottenham Court Road Elizabeth line station is a new station located in the heart of London, adjacent to Oxford Street, being delivered as part of the Crossrail programme. The station is expected to accommodate more than 200 000 passengers every day when it becomes operational in December 2018. The station is of paramount importance due to its strategic location, interchange with the London Underground and future link to Crossrail 2.
Tottenham Court Road consists of two entrances on the east (Goslett Yard Box) and west (Western Ticket Hall) sides of Soho Square, each of which has a ventilation tower equipped to ventilate the 250m long new platforms and running tunnels located 25m below ground. The ventilation towers are two of the largest overground structures on the entire Crossrail project, and presented a vast array of challenges due to their locations as well as their technical complexity.
Following the award of the contract to Laing O’Rourke, discussions were held about changing the design of the superstructures to precast concrete. However, due to the design process that would have been required to alter the concept, and lead time for bespoke precast elements, there was not sufficient time to alter the construction methodology. Therefore, a traditional in situ concrete approach was used. In fact, due to the precise planning and coordination of this approach, it resulted in a more economical solution than the precast option.