Innovative Drainage Solution for The OWO – Latest
Our development infrastructure team's innovative drainage solution for The OWO, a new landmark Raffles hotel, has been featured in New Civil Engineer' magazine.
In the ‘Innovative Thinking’ feature, Head of Development Infrastructure Paul Davis, explains how their subterranean drainage approach saved time, money and materials on the project.
The adaptive reuse of the former War Offices into a luxurious Raffles at The OWO necessitated the creation of four additional basement levels beneath the existing. This posed challenges due to the need to excavate deep into the London Clay strata. Without intervention, this would cause long-term hydrostatic pressure on the underside of the new basement box.
The team devised an innovative subterranean drainage solution, seeing the installation of a porous layer of no-fines concrete on the underside of the slab. Allowing groundwater to be continuously collected and drained to a sump and reducing hydrostatic pressure.
By using this approach, the team eliminated the need for 36 plunge tension piles - each 50 metres long and 900mm in diameter - which would have been necessary to counteract the hydrostatic uplift. As a result, the project benefited from significant cost and time efficiencies.