Viaduc de Millau

1. Viaduc de Millau

4. Project timeline 28 June1989: governmental approval of the middle route 19 October1991: selection of the high solution, with the viaduct at 2500 m 10 January1995: declaration of utilité publique (public usefulness), as needed to apply eminent domain or compulsory purchase. 9 July1996: choice of the cable-stayed bridge type 1998: decision to contract out both construction costs and future tolls to a private enterprise 16 October2001: work begins 14 December2001: laying of the first stone January 2002: laying pier foundations March 2002: start of work on the pier support C8 June 2002: support C8 completed, start of work on piers July 2002: start of work on the foundations of temporary, height adjustable roadway supports August 2002: start of work on pier support C0 September 2002: assembly of roadway begins November 2002: first piers complete 25 February–26 February2003: laying of first pieces of roadway November 2003: completion of the last piers (Piers P2 at 221 m and P3 at 245 m are the highest piers in the world.) 28 May2004: the pieces of roadway are several centimetres apart, their juncture to be accomplished within two weeks 2nd half of 2004: installation of the pylons and shrouds, removal of the temporary roadway supports 14 December2004: official inauguration 16 December2004: opening of the viaduct, ahead of schedule 10 January2005: initial planned opening date

6. Preliminary studies • In initial studies, four options were examined: • bypass Millau to the east, requiring two large bridges over the Tarn and the Dourbie; • bypass Millau to the west (12 km longer), requiring four bridges; • follow the path of Route Nationale 9, providing good access to Millau but at the cost of technical difficulties and intrusion on the town; and • traverse the middle of the valley. • The fourth option was selected by the government on 28 June1989. It consisted of two possibilities: the high solution, and the low solution, requiring the construction of a 200 m bridge to cross the Tarn, then a viaduct of 2300 m extended by a tunnel on the Larzac side. After long construction studies, the low solution was abandoned because it would have intersected the water table, had negative effects on the town, cost more, and the driving distance would have been longer. • After the choice of the high viaduct's path, five teams of architects and researchers simultaneously worked on a technical solution. The original concept for the bridge was devised by French designerMichel Virlogeux. The architects of the bridge are the British firm Foster and Partners. They worked together with the Dutch engineering firm ARCADIS, responsible for the technical design of the bridge.

11. Costs and resources • The bridge's construction costs amount to €394 million, with a toll plaza 6 km north of the viaduct costing an additional €20 million. The builders, Eiffage, financed the construction in return for a concession to collect the tolls for 75 years, until 2080. However, if the concession is very profitable, the French government can assume control of the bridge in 2044. • The project required about 127,000 m³ of concrete, 19,000 metric tons of steel for the reinforced concrete, and 5,000 metric tons of pre-stressed concrete for the cables and shrouds. The builder claims that the bridge's lifetime will be at least 120 years.

12. Statistics • 2,460 metre: total length of the roadway • 7: number of piers • 77 m: height of Pier 7, the shortest • 343 m: height of Pier 2, the tallest (245 m at the roadway's level) • 87 m: height of a pylon • 154: number of shrouds • 270 m: average height of the roadway • 4.20 m: thickness of the roadway • 32.05 m: width of the roadway • 85,000 m³: total volume of concrete used • 290,000 metric tons: total weight of the bridge • 10,000–25,000 vehicles: estimated daily traffic • €4.90–6.50: typical automobile toll, as of 2005 • 20 km: horizontal radius of curvature of the road deck