Millau Viaduct 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. Twelve fibre optic extensometers were installed in the base of pylon P2. Being the tallest of all, it is therefore under the most intense stress. These sensors detect movements on the order of a micrometre. Other extensometers, electrical this time, are distributed on top of P2 and P7. This apparatus is capable of taking up to 100 readings per second. In high winds, they continuously monitor the reactions of the Viaduct to extreme conditions. Accelerometers
A75 autoroute Massif Central is, in itself, a formidable achievement. Much of the motorway runs at an altitude in excess of 800 m (2600 ft) with 50 km in excess of 1000 m (3250 ft). The single most impressive feature is undoubtedly the Millau Viaduct, which carries the road over the Tarn. It was constructed under a government contract with the Eiffage group, effective for 75 years. Eiffage collects tolls at agreed rates making this the only tolled part of the A75. Other impressive features include: Viaducts and bridges Passes Tunnels In May 2007, construction started on the final section of the