Conway and Britannia tubular bridges: Stephenson's team

The paper reviews the significant achievements of Robert Stephenson and his team in the innovative design and construction of Conway and Britannia tubular bridges. The text is based on extensive extracts taken from contemporary accounts by two members of Stephenson's team, William Fairbairn and Edwin Clark. The paper describes the sequence of model tests (from initial small-scale tests, followed by one-sixth scale tests to tests on the first Conway tube) and the methods used to overcome the problems of buckling that were identified in the experimental work. The innovative method of floating and raising the tubes into their final location is also reported. In addition to strength and stiffness considerations, Stephenson's team also investigated the effects of temperature and wind loading and in these studies developed an accurate method of measuring deflections. It is suggested that the design and construction of Conway and Britannia Bridges could provide an excellent case study for undergraduate and postgraduate students studying structural behaviour and, in particular, the problems associated with buckling.