Bridge+Project

The Millau’s bridge.
It’s full name is Le Viaduc de Millau, and it is located in France, between the communes of Millau and Creissels, in the département of Aveyron. The bridge was built in order to help to cross the valley of the Tarn river.

Its design is deeply related to the search for an aesthetically structure, led to the choice of a multi- cable- stayed viaduct with slender piers and a very light deck, touching the valley at only seven points. The two persons envolved in its design were Michel Virlogeux who’s a French engineer and Norman Foster, a recognized British architect.

It is a cable stayed bridge, which means that it is a Bridge whose deck is supported at several points by stays and rests on one or more towers, and its deck and pylons are entirely of metal, exactly steels of grade S355 and S460. The Millau’s bridge has a total length of 2,460 m, width 32 m, and its longest span is 342 m.

In the technological aspects, we got to say that the electrical installations of the viaduct are impressive, there are 30 km of high-current cables, 20 km of fiber optics, 10 km of low-current cables which are situated on the deck, on the pylons and on the masts. In the instrumentation field, the viaduct is state of the art. The pylons, deck, masts and stays are equipped of sensors, these are designed to detect the slightest movement in the viaduct and measure its resistance. Twelve fiber optic extensometers were installed in the base of pylon P2, these sensors detect movements on the order of a micrometer. 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. Additionally, two piezoelectric sensors gather traffic data: weight of vehicles, average speed, density of the flow of traffic, etc. This system can distinguish between fourteen different types of vehicle.

//__**Advantages: **__//
 * 1) The Millau Viaduct is equipped with safety barriers built to withstand truck impacts.
 * 2) The Viaduct’s trajectory respects the area’s major natural sites and the exceptional landscapes of the confluence of the Dourbie and Tarn valleys
 * 3) The factory pre-production of certain parts of the deck reduced the volume of material that had to be worked on-site.
 * 4) Thanks to the “viaduct effect”, the mayor of Millau approved more than 100 building permits in 18 months for the construction of three hotels plus other businesses and industries. Millau has seen an economic boom since the bridge opened.
 * 5) The two industrial zones in La Cavalerie to the south, and Sévérac-le-Château to the north, have both expanded greatly, accommodating new enterprises both local and national.
 * 6) Is an excellent example of a sustainable solution for a transport problem in a situation where economic and ecological interests appeared to be virtually irreconcilable.

 //__**· Disadvantages:**__//  The Millau Viaduct really doesn’t present major disadvantages but before its construction numerous organizations opposed the project, including the WWF, France Nature Environnement, the national federation of motorway users, and Environmental Action an they put forward several arguments.
 * 1) The westernmost route would be better, longer by three kilometers but a third of the cost with its three more conventional structures.
 * 2) The project would never break even; toll income would never amortize the initial investment and the contractor would have to be supported by subsidies.
 * 3) <span style="color: #800080; font-family: Tahoma,Geneva,sans-serif;">The technical difficulties were too great and the bridge would be dangerous and unsustainable; the pylons, sitting on the shale of the Tarn Valley, would not support the structure adequately.
 * 4) <span style="color: #800080; font-family: Tahoma,Geneva,sans-serif;">The viaduct represented a detour, reducing the number of visitors passing through Millau and slowing its economy

media type="custom" key="5415659"