Viaduc de Millau

Project timeline 28 June28 June 1989: governmental approval of the middle route October19 October 1991: selection of the high solution, with the viaduct at 2500 m January10 January 1995: declaration of utilité publique (public usefulness), as needed to apply eminent domain or compulsory purchase.1995eminent domain 9 July9 July 1996: choice of the cable-stayed bridge type : decision to contract out both construction costs and future tolls to a private enterprise 16 October16 October 2001: work begins December14 December 2001: laying of the first stone2001 January 2002: laying pier foundations2002 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 February25 February–26 February 2003: laying of first pieces of roadway26 February2003 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 May28 May 2004: the pieces of roadway are several centimetres apart, their juncture to be accomplished within two weeks2004 2nd half of 2004: installation of the pylons and shrouds, removal of the temporary roadway supports 14 December14 December 2004: official inauguration December16 December 2004: opening of the viaduct, ahead of schedule January10 January 2005: initial planned opening date2005

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 June 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.28 June1989Larzac 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 designer Michel 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.designerMichel VirlogeuxFoster and PartnersDutchARCADIS

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 However, if the concession is very profitable, the French government can assume control of the bridge in 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.m³

Statistics 2,460 metre: total length of the roadwaylength 7: number of piers 77 m: height of Pier 7, the shortestheight 343 m: height of Pier 2, the tallest (245 m at the roadway's level) 87 m: height of a pylonpylon 154: number of shrouds 270 m: average height of the roadway 4.20 m: thickness of the roadway m: width of the roadway 85,000 m³: total volume of concrete usedm³volume 290,000 metric tons: total weight of the bridgemetric tons 10,000–25,000 vehicles: estimated daily traffic €4.90–6.50: typical automobile toll, as of 2005€as of km: horizontal radius of curvature of the road deck