Last week French president Jacques Chirac officially opened the Millau Viaduct in southwest France - the spectacular, crucial link in the Paris to Barcelona motorway, writes Andrew Mead
Designed by Foster and Partners with engineer Michel Virlogeux, the 2.46km-long cable-stayed bridge has ‘the highest elevated roadway in the world’. Supported on seven concrete piers of varying height, its deck is 270m above the River Tarn. But while the viaduct is undeniably dramatic, it is surprisingly graceful too. It doesn’t so much dominate the gorge-andplateau landscape as integrate with it.
The French government selected the design in 1996 after an invited competition. It later awarded a 75-year operating concession on the viaduct to contractor Eiffage, which built and financed it at a total cost of .320 million (£220 million). Construction began in October 2001, and now Eiffage can start recouping its expenditure through tolls.
A 3 per cent slope from south to north encourages drainage, while a gentle curve as the bridge approaches the northern plateau helps wind resistance; winds here can be very strong. But both these factors work aesthetically too, accentuating the sense that the structure is tailored precisely to a specific site.
This marriage of the functional and aesthetic continues in the tapered concrete piers, which bifurcate towards the top to cope better with thermal movement in the steel deck (trapezoidal in section), while making the supports seem more slender. Further increasing that impression is the faceting of the lower reaches of the piers, which are strongly modelled when the sun shines, their bulk eroded by shadow.
It’s clear that the Millau Viaduct won’t just be a swifter route to somewhere but a destination in its own right. There is a visitor centre on the south bank, but the best views of all come from the old hairpin-curve roads that climb up on either side from the River Tarn. These will be great for sightseeing - at least for passengers.