'Comparatively straightforward' appears a somewhat surprising comment from the contractor charged with installing £40M worth of foundations for Heathrow Airport's new fifth passenger terminal. And the company, Bachy Soletanche, now working flat out on one of Europe's largest geotechnical contracts, is employing eight piling rigs and a 100-strong site team to provide virtually its full arsenal of foundation techniques including bored, contiguous and under-ream piles, plus ground anchors, stone columns, slurry and diaphragm walls.
But the key word is 'comparative'; for the geotechnical specialist's project manager Rob Jackson is comparing the strictly technical task of pile and wall formation with his team's real challenges - the logistics of providing such a range of foundations on a congested, multi activity site and all within the terms of a new style framework contract which counters no outturn cost or time overrun.
"Pile installation into underlying London Clay is not technically demanding " he says. "But sinking 16 piles every day on a confined site where storage of literally anything is strongly discouraged, turns delivery of the right materials to the right place at the right time into a major logistics exercise."
Client BAA's £3.7Bn scheme centres on a main 384m long eight storey core terminal. This will ultimately be supported by two satellite buildings, though only the first is being built during the initial phase due for completion in 2008.
Numerous cut and cover service ducts and pedestrian subways will link the buildings. Beneath the lot, major new tunnels are needed to feed extensions of the Heathrow Express and Piccadilly Line Underground direct to the futuristically designed terminal.