Born out of frustration from the annual bottleneck caused by Parisians traveling south on the Autoroute 75 to the Mediterranean each summer, the French government requested in 1993 a proposal for the Millau Viaduct, which would be a high bypass between plateaus at the top of a gorge. It opened in 2004 and immediately went into the Guinness books: a) the highest road deck in Europe; b) the longest launch of a bridge deck; c) the tallest piers in the world; and, d) the highest bridge tower in the world. The Viaduct even surpassed the Eiffel Tower as France’s tallest structure.
But it was the beauty, its elegant and artistic design, that caught the eye and heart, of the public. The architect had scribbled the words “light & lightness” at the top of his sketches for the bridge and those key concepts can be found throughout its design. The team at Foster + Partners Architects were guided by their desire to reduce the structure and its visual elements to their minimal essentials. Mr. Foster “wanted the structure to look as delicate as possible, almost floating. I wanted motorists to feel as if they were flying their cars.”
The foundations were massive and buried deeply into the ground so that the piers would appear to pierce the ground “like blades of grass” with no apparent support system. Each pier was formed as a hexagon with its multiple facets reflecting at different angles which minimized its visual size and mass to the eye, plus the piers were tapered as they rose to reduce their weight and minimize their visual impact. Far above the buildings below, the piers were split to provide two vertical grooves which would support each roadbed allowing them to flex with the structure absorbing the movement of the roadways. This design created a structural spine which allowed the designers to attach the bridge’s cables to a single center row, rather than the more common double set of cables on each side of the roadbed. The roadbed was built on a 12 mile curve enabling drivers at either end to see all seven piers as the approach the viaduct.
The bridge solved a decades old problem in a graceful, gentle and tranquil manner.