UnderstandPresentation of the Viaduct Millau Viaduct: a structure, a heritage An exceptional structure in every way The Millau Viaduct rises majestically above the Tarn valley. Brought into service in December 2004, the structure receives hundreds of thousands of visitors every year: tourists, architecture enthusiasts, journalists as well as motorists. Opening up the Massif Central and attracting a flood of visitors was only one step – be it a giant's one – away. Back to the advent of a unique project. Viaduct vs bridge No difference in engineering structure is implied by the words "bridge" and "viaduct"; both enable a supported route to span an obstacle. A bridge simply links two sides whilst a viaduct links two very high points. Architecture and aesthetics By its modernity and sheer size, the viaduct is guaranteed to impress. The collaboration between Michel Virlogeux, chief engineer, and Lord Norman Foster, architect, was a success: the Millau Viaduct was hailed as a major architectural structure of the 21st century. The dream needed to be made a reality, and Eiffage rose to and met the challenge. A multi-stayed civil engineering structure reminiscent of a yacht The stays, monumental cables that ensure the deck maintains its horizontal position, are a strong part of the viaduct's identity. Following a call for tenders from the French government, the multi-stayed solution was selected in 1996 from four alternatives: a bridge of uniform thickness, a bridge of variable thickness, a viaduct with sub-bended spans and a structure with a single central arch. The aesthetics of the structure appealed to the government departments. Despite the unusual size and decidedly modern architecture, the Millau Viaduct blends perfectly into the surrounding landscape. It provides a link between two worlds: the Grands Causses and that of contemporary art. A monumental project, masterfully executed Strictness, precision and professionalism were the order of the day for each stage of construction. It should be noted that the selected project broke many records! Armed with concrete, steel and determined workers, Eiffage carried out the project. The history of the Viaduct: from planning to construction Sketch by Norman Foster The viaduct may have been built in 3 years, but preparation for the project took 14. The first discussions on the crossing of the Tarn near Millau took place in 1987. As the final section of the A75 motorway, the Millau Viaduct is without a doubt the biggest technical and institutional challenge ever faced by this motorway. Creation of the structure The A75 and the Millau Viaduct are the fruit of significant planning. Opening up the Massif Central was a major concern in the second half of the 20th century. From this issue was born the association "La Méridienne", which contributes, even today, to enhancing and revitalising the surrounding regions. Design A new call for tenders was launched by the French government for the concession of the viaduct. The combination of concrete and steel, recommended by Eiffage, was decided on in 2001. The Compagnie Eiffage du Viaduc de Millau was put in charge of both the construction and operation of the viaduct. Construction: Three years for a monumental project The first stone was laid on 14 December 2001. The adventure was underway for construction workers! After only a few weeks, the first piers of the viaduct began to rise up, until the world record for the highest pier was achieved, at 245 m. The concreting was completed on schedule in December 2003. Two open construction sites were in operation simultaneously to prepare the deck. On 25 February 2003, an initial deck section measuring 171 m was launched into the void. 17 more followed suit meaning that on 28 May 2004, at 2:12 p.m. precisely, the northern and southern ends of the deck could be joined. An operation carried out 270 metres above the Tarn. Mission accomplished! Then everything came together... installation of the pylons began 24 hours after the deck was joined, followed by installation of the 154 stays to support the deck. In three months, everything was finished. In late September, the deck was surfaced. After the road had been prepared for vehicles, safety assemblies and lighting installed, and the finishing touches put on the toll gate, on 14 December the structure was inaugurated by the President of the Republic. 16 Decembrer 2004: the viaduct was brought into service.