Re-useable casing plays a key part

Re-usable pile casings have held a key role in one of Britain's biggest piling contracts, at the M11 link road in east London.

The casings were used by Cementation Piling & Foundations to help build a retaining wall along a 2.4km long stretch of dual carriageway for the M11 to A12 link at Leytonstone. The second phase works for the project called for 5,000 permanent piles costing œ20 million.

Nearly 30 temporary pile casings were sunk up to 9m deep to hold back unstable ground in advance to rotary boring. The casings were rolled from 8mm thick plates into 1.875m diameter units and can be extrated for re-use.

Manufacturer T.H.E Section Bending Co. formed "keyhole" slots at the top of each casing to extract the units for re-use once permanent concrete and steelwork had been put in place. The company is understood to have worked around-the-clock for two weeks to meet the piling contractor's special order.