Millau Viaduct mid-1998. After undergoing wind tunnel tests, the shape of the road deck was altered, and detailed corrections were made to the design of the pylons. When the details were eventually finalised, the whole design was approved in late 1998. Once the Ministry of Public Works had taken the decision to offer the construction and operation of the viaduct as a grant of contract, an international call for tenders was issued in 1999. Five consortia tendered: Piers were built with Lafarge high performance cement. The pylons of the Millau Viaduct, which are the tallest elements (the tallest pylon – ) were
Millau Viaduct Vinci Group specialising in prestressing. It installed the cable stays and put them under tension, while the prestress division of Eiffage was responsible for prestressing the pillar heads. The steel road deck, and the hydraulic action of the road deck were designed by the Walloon engineering firm Greisch from Liège, Belgium, also an information and communication technologies (ICT) company of the Walloon Region. They carried out the general calculations and the resistance calculations for winds of up to . They also applied the launching technology. The sliding shutter technology for the bridge piers came from PERI. The bridge's construction cost