Fleming Award: ground improvement for a seismically qualified facility is the winner

The delivery of an innovative ground engineering solution for a defense related production facility, which met an extensive range of performance criteria in challenging ground conditions, has won this year’s British Geotechnical Association Fleming Award.

At the ceremony, held in person at the Institution of Civil Engineers on Tuesday evening (6 December), BAE Systems, Atkins, Bachy Soletanche and Morgan Sindall were named the winners by a panel of judges headed up by Gavin and Doherty Geosolutions director Yvonne Ainsworth.

The project to install a heavy duty reinforced concrete extension to the production facility was particularly challenging since half the site is over an infilled dock with the dock wall retained insitu. The other half is an extension built in Victorian fill. The extension required a thick reinforced concrete foundation raft, but analysis demonstrated excessive settlement and a liquefaction hazard.

The innovative ground engineering solution was a raft supported on a honeycomb grid of 1,700 secant piles. This replaced 10m of poor-quality backfill, eliminating liquefaction, safety and settlement risks. Trials were undertaken to ensure construction feasibility, tolerance compliance, acceptable ground settlement and reliability.

A pile pull-out test was completed to prove the secant interlock joint strength was sufficient to ensure a seismic elastic response in the pile block.

Atkins chief geotechnical engineer Andy Thomson said: “We were faced with the most onerous design criteria combined with the worst possible ground conditions. This required collaboration between BAE, ourselves (Atkins) and all the contractors involved, and major innovations throughout the project.”

Ainsworth said that all the presentations described “excellent and challenging projects”.

The winning team, however, stood out for its “well-structured presentation, which showed a collaborative client/contractor/consultant approach to deliver a project in complex geology".

“In their own words they said they were faced with the most onerous performance conditions in the most unfavorable ground conditions,” said Ainsworth.

During the deliberations, a short keynote lecture was given by Sergio Solera of Mott MacDonald on the design and construction of new tidal barrier and quay walls at the Port of Boston, UK.

The other finalists were:

• A heat exchange piled foundation solution at the Euston station welfare facility for High Speed 2 (HS2) - Keltbray, City, University of London, G-Core, Wentworth House Partnership, Mace-Dragados and HS2 Ltd
• HS2 Phase One, Contract C1 - Align integrated project team: HS2 Ltd, Bouygues Travaux Publics, Jacobs, Rendel-Ingerop and Keller

BAE Systems, Atkins, Bachy Soletanche and Morgan Sindall’s ground improvement work on the defence facility won the UK Project with a Geotechnical Value over £3M category at this year’s GE Awards.

The Fleming Competition is held annually to commemorate the life and work of piling engineer Ken Fleming. It aims to recognize excellence in the practical application of geotechnics in a project or as part of a project.