Geotechnical
Specialists
Bachy Soletanche goes piling by the dock at London’s Crossharbour site
Leading geotechnical specialist, Bachy Soletanche Limited has
recently completed its first stage of piling works at
Crossharbour, the high-profile development based in London City
centre – constructing a secant wall around the perimeter of the
site. The former London arena site is based in the heart of the
Canary Wharf and Docklands business district and is one of the
largest ongoing construction sites in London City centre.
The prestigious waterfront location is planned to provide a
myriad of facilities comprising 1047 residential apartments,
285,846 sq ft of offices, a four star hotel and a combined
40,846 sq ft of retail, restaurants and leisure facilities.
Barry Osborn, contracts manager at Bachy Soletanche Limited,
commented:
“Currently the site leaves a redundant space on the Millwall
Inside Dock, however construction works are well underway as
Bachy Soletanche has recently completed the secant wall piling
works.”
“We were awarded the initial piling work for the secant wall
in October last year and within four months the approximately
577lm long wall is now complete and ready for excavation” He
added.
The initial secant wall contract comprises of approximately 970
secant piles, and due to the ground profile and the client
requirement of a strict 1:200 tolerance two processes are being
utilised to construct the wall.
Barry Osborn explains:
“The use of two different processes is required for the
construction of the female and male piles
as the design requires complete accuracy. This is mainly due to
the waterfront location of the site ensuring that the wall is
completely watertight before excavation.”
The female piles were drilled to a depth of 14metres and
constructed prior to the male piles using a bespoke piling
method designed by Bachy Soletanche.
Barry Osborn commented:
“Once the female piles were installed the 485 male piles were
ready to construct. These used a longer length casing at
17metres, had a stronger concrete mix and a different
installation method to the female piles.”
The 750mm diameter male piles, with a 14metre depth were
drilled using 17metre casings with the same length auger string.
These piles were drilled utilising a cased continuous flight
auger method (CSP), which was the preferred method due to the
structure of the ground which at 14metres had a clay layer -
forming a natural seal for the toe of the wall.
With the secant walls complete, Bachy Soletanche will remain on
site as the geotechnical firm was awarded the main works
contract for the bearing piles and the capping of the secant
wall.Barry Osborn concluded:
“The original on-site time scale at Crossharbour was four
months but then we were awarded the main works contract,
extending the programme by another two months.”
“This caused a cross over for both the secant wall contract and
the bearing piles contract, which resulted in the need for
careful co-ordination to ensure the project ran smoothly.
However, now the secant wall is complete we can concentrate on
the bearing piles which are due to be completed in April”
Email:
alex@manifestcomms.co.uk