The observational method – engineering’s best kept secret

The observational method has been used to deliver some of the world’s most challenging projects safely and cost effectively. And yet, very few people know about it. Our engineers are working to change that.

From the Channel Tunnel in the 1980s to Boston’s ‘Big Dig’ highway programme in the 90s, raising Wembley’s iconic arch in 2004, excavation of deep shafts on the Elizabeth Line and current earthworks on HS2, this powerful methodology has been used to minimise risk and maximise efficiency in underground construction. In some cases it has been the only way to safely deliver complex underground works or rescue projects from difficulty.

Used in raising Wembley’s iconic arch in 2004, the observational method has been used to minimise risk and maximise efficiency in underground construction.

In our latest heritage podcast with Engineering Matters, our award-winning geotechnical engineers describe how they pioneered the method on some of the world’s biggest projects.

“Its outstanding success in the 1980s, when applied to the Channel Tunnel, paved the way for a whole series of very successful applications on major infrastructure projects over subsequent decades,” recalled Alan Powderham, former Mott MacDonald director of transportation, when interviewed for the podcast.

Later applications included the raising of Wembley Stadium’s iconic arch. Twenty years on from that spectacular achievement, geotechnics practice lead Tony O’Brien explains why the observational method was key to managing the massive and complex loadings on foundations for the arch itself and the multiple jacks and turning struts used to raise it into position.

Its outstanding success in the 1980s, when applied to the Channel Tunnel, paved the way for a whole series of very successful applications on major infrastructure projects over subsequent decades.

Listen now to find out more and hear from more of our experts including geotechnical director Rob Talby, technical principal Hock Liong Liew, and graduate civil engineer Sophie Smith. We also talk to HS2 Phase 2 engineering director and former Mott MacDonald engineer Alistair Hitchcock.