Features

• The Millau Viaduct is supported by seven concrete pylons,each range in height from 77 to 246 m, and taper in their longitudinal section from 24.5 m at the base to 11 m at the deck. Each pylon is composed of 16 framework sections, each weighing 2,230 tons. These sections were assembled on site from pieces of 60 tons, 4 m wide and 17 m long, made in factories in Lauterbourg and Fos-sur-Mer by Eiffage.

• The seven masts, each 88.92 m high and weighing around 700 tonnes, are set on top of the pylons. Between each of them, eleven stays (metal cables) are anchored, providing support for the road deck.

• The metallic deck, which appears very light despite its total mass of around 36,000 metric tonnes, is 2,460 m long and 32 m wide. It comprises eight spans. The six central spans measure 342 m, and the two outer spans are 204 m.

• To allow for deformations of the metal deck under traffic, a special surface of modified bitumen was installed by research teams from Appia. The surface is somewhat flexible to adapt to deformations in the steel deck without cracking, but it must nevertheless have sufficient strength to withstand motorway conditions (fatigue, density, texture, adherence, anti-rutting, etc.). The "ideal formula" was found only after ten years of research.

• The pylons, deck, masts and stays are equipped with a multitude of sensors. These are designed to detect the slightest movement in the viaduct and measure its resistance to wear-and-tear over time. Anemometers, accelerometers, inclinometers, temperature sensors are all used for the instrumentation network.