The station box for the new Canary Wharf Crossrail Station is being constructed within a tubular steel cofferdam. The tubular piles were installed by Giken on behalf of Expanded Ltd., and form a cofferdam in 10m of water in North Quay. The tubes are 900mm in diameter and 18m long.
Tony Gee was engaged to design the watertight interlock and to determine a safe push-in force for the tubes that prevented damage and loss of interlock.
The interlock and main tubes had to be designed to ensure acceptable stresses and strains during deflection of the retaining wall when the dock is dewatered and exaction begins.
The structural analyses of the tubes was undertaken using non-linear plane strain 2-D finite element package – LUSAS.