The project comprises five shafts, with the diaphragm walls the deepest undertaken in the UK at 90m. A 7m-diameter 7km-long tunnel connects the shafts. The steel-fibre-reinforced concrete for the slipformed tunnel lining took 18 months to develop, resulting in a self- compacting concrete with a retention time of four hours encompassing up to 15 constituent materials. The innovative slipformed shaft construction also incorporated steel fibres to reduce substantially the quantity of standard reinforcement.

Richard Kershaw of Cemex UK Materials, concrete supplier to the project, said, “We are very honoured to receive such acclaim from this most prestigious of awards. Concrete was the only realistic material choice for this structure. CEMEX is proud to be part of this momentous scheme and be part of a legacy to London, which will help prevent 16 million tonnes of sewage entering the River Lee and Thames each year.”

The Society Awards judging panel said, “The Lee Tunnel was the most outstanding structure and therefore outright winner for its technical achievements in the use of concrete, its demanding placement conditions and innovative structural solutions. The statistics for concrete volume placed are impressive; the innovation required and final execution is exemplary. This project pushed the technical boundaries of what is possible with concrete.”

Over 400 members, guests and construction industry representatives attended The Concrete Society Awards Dinner held at the Grosvenor House Hotel, Park Lane, London on 17 November 2016. This event celebrates excellence in concrete and is the longest-running awards programme in the UK construction industry, now in its 48th year.