JSD 80th Celebration and the ISE Presidential Visit. For those at UCT’s Chem Engi Seminar Room privileged to listen to ISE President Ian Firth on Engineered Elegance – the Art of Bridge Design, this was a real treat. He started by quoting Marcus Vitruvius, the famous Ancient Roman architect, who believed that an architect should focus on three central themes when preparing a design for a building: firmitas (strength), utilitas (functionality), and venustas (beauty). The bridge designer must deal with strength and stability, buildability and maintainability, economy and much more, but should not neglect the venustas, with scale and proportion, light and shade and the contextual being of great moment.
One of the earliest examples he noted of the latter was the Great Belt East Bridge in Denmark, where the architect had in his office a multitude of models of the towers, with different numbers of cross-members at different levels, where he’d come to realize how important such things could be. He also liked the anchorages of the catenaries, seeing them as beautiful examples of form following function (tremendous forces to be coped with without overturning or over-stressing the foundation or being overly bulky). Interesting: the deck is only laterally supported at the towers, not in the vertical.
Mr Firth admitted to being influenced by Calatrava but said that Calatrava was not always practical, claiming that the Alamillo Bridge, for example, was not to be easily maintained. He works with architects, but only a very select few. Inevitably, Millau Viaduct had to come up – he seemed to have divided loyalties on this, recognizing the Engineer (Michel Virlogeux) whose idea it was, but equally impressed by British architect Norman Foster’s role.
Other beautiful bridges included the Sunniberg, Salginatobel and the Gateshead Millenium, with his own Swansea Sail Bridge not looking too shoddy.
Mr Firth showed a clip of the Millenium Bridge (near the Tate Modern) on the day it was opened and closed, with the people first staggering around because of the wobble and then trying to synchronise their efforts.
His firm, Flint & Neill, subsidiary of COWI International, was called in by Arup (who designed it) to fix what Arup claimed was an unknown effect at the time (not true). He’d been on the Boomslang in Kirstenbosch and confessed to having tried to get it to misbehave. (No comment from Engineer Henry Fagan, in the audience)
