As contractors start mobilizing to drive Crossrail’s twin tunnels, work on the railroad’s $795-million station at the Canary Wharf commercial district in east London is powering ahead. The six-floor-deep station is the largest of Crossrail’s nine.
Top-down construction is forming the station along the River Thames. The structure will extend 25 meters below the water level. Construction within a watertight cofferdam is scheduled to greet tunnel-boring machines in summer 2012.
Canary Wharf Group plc., the project owner, in December 2008 agreed with the government to design and build the station for a fixed price. Canary Wharf Group also committed around $240 million to the station’s funding; the group’s construction unit, Canary Wharf Contractors Ltd., is handling design and construction. London-based Foster + Partners is the architect for the four-floor retail component.
Piling for the large cofferdam to enclose the station at the River Thames dockside site started in May 2009. More than 290 1.2-meter-dia steel-tube piles were driven, through which 38-m-long concrete piles were bored.
Dewatering started last February at the 256-m-long, roughly 40-m-wide cofferdam, reaching some 10 m below the water level.
The cofferdam’s concrete base will form the roof of the station ticketing hall. Workers have begun excavating below the concrete, allowing a second slab to be built later some 5 m below.
The process will be repeated to form the railroad track slab. Work is within budget and scheduled for a 2015 completion, says a Canary Wharf spokesman.