Permanent Cofferdam for basement construction
PU22-1mm in 10.0m lengths
Made ground, overlaying sand and gravel, overlaying London clay.
The project at Ewer Street, Southwark, London, involved building a new eight storey student accommodation block.
Elliott Thomas appointed Fussey Piling on the £140k project, to design and install a permanent cofferdam, including framing, to enable the excavation and construction of the basement.
The ground conditions encountered were made ground to a depth of approximately 0.5m, overlaying sand and gravel to approximate 6.5m, overlaying the London clay. Therefore, to ensure that the piles entered the ground smoothly, the ground was pre-augered before instillation, using the auger motor mounted on the RTG16T.
The sections used were 10.0m PU22-1mm piles, steel grade 355GP in a cofferdam 23.0m x 15.8m internal.
The site bordered a network rail viaduct which had the Jubilee Line running underneath and so vibration had to be kept to an absolute minimum. To this end, Fussey used a ‘silent and vibration-free’ technique to install the piles, utilizing the WP150, with one of their Sennebogen crawler Cranes.