A COFFERDAM at the site of a new Holiday Inn in west London will not only support the basement but protect it from flooding if the nearby River Brent bursts its banks.
Main contractor Bowmer & Kirkland originally intended using a slurry cut-off wall at the site for the five-storey building in the centre of Brentford.
This was needed to support the basement for the £8M design and build project which includes an underground car park.
Instead, subcontractor Aarsleff Piling suggested using a steel sheet pile wall which, as well as encapsulating the site, will protect it if the river floods during very high spring tides.
The 340 piles are being driven through 3m of made ground which lies on alluvial gravel deposits, and 6-7.5m into the underlying London Clay. But because the piles range in length from 9-11m, they will stand above the retained material.
A Banut 700 fixed leader hydraulic piling rig with full noise shrouded 5t drop hammer is driving the 340 piles needed for the 203m excavation perimeter.