Michel Virlogeux: strength, utility, beauty

Probably nothing captures the spirit of bridge engineering as much as the famous Vitruvian triad: firmitas, utilitas, venustas (strength, utility, beauty). How to harmoniously combine all these aspects in order to create a perfect structure?

Michel Virlogeux: I think the order should be different. Personally, I would start with utilitas, or utility. Then I would move on to firmitas and venustas, that is, resistance and durability, and beauty. Utility and durability are extremely important also in the aspect of managing public money transferred for construction. You have to be reasonable about the cost of construction. This is the art of engineering. And when it comes to beauty... I will repeat it once again – the structure of a bridge must be adapted to the place where it is to be located. This is actually the most important issue.

The design must be harmonised with the site, be adequate. For example, when a bridge is built in Brittany, where granite rock can be found practically everywhere, the design must be and look strong, and in the case of the Normandy Bridge, located over a flatplain and a wide estuary, it must appear as a toned-down structure. It must give the impression of piece and be rather slender.

Your view on the work of architects designing bridge structures is well known (“To design a bridge is to master forces, and this is not the job of the architect”). Why do you think it is so important that the design of the bridge is left to an engineer?