Collaboration in an emergency: repairing London's M4 Boston Manor viaduct

Three months before the opening of the London 2012 Olympic Games, over 100 cracks were found in the electroslag welding of the massive 1 km long Boston Manor viaduct in west London. The 1960s structure carries the M4 motorway into London from Heathrow airport and formed a vital part of the Olympic route network, so repairs were needed urgently. This paper describes how the various stakeholders formed a unified team to direct and execute the painstaking £8 million repair project within just 16 weeks, and how they benefited from the Lean technique of collaborative planning.