Potential benefits and pitfalls of the observational method were shared at an evening meeting of the British Geotechnical Association’s Early Career Group last week.
Retired Mott MacDonald transportation division director Alan Powderham delivered his Vienna Terzaghi Lecture on the subject including four case studies to outline the practical application of the approach.
After outlining the main attributes of the technique and how it may be used to provide a vehicle for risk management, value enhancement and safety in design and construction, Powderham went on to explain the limitations.
According to Powderham, the observational method cannot be used in adverse contractual or commercial environments nor where sudden/brittle failure may occur.
Powderham used the application at Heathrow to explain how it can be used to overcome programme issues and the use in Boston to review the benefits for constrained sites with complex ground conditions.
Event attendee Mott MacDonald assistant geotechnical engineer Frederick Levy said: “It was demonstrably shown throughout that with the appropriate application of instrumentation, engineering judgement and close collaboration between client, contractors and designers, the method can to lead enhanced certainty for clients and make safety a driver for innovation.”