Onward to Millau
28 May 2009
|Thurs 28th May---Weather:-Sunny/24 degrees
Nice to Millau (416km) (5:00h)
So here we find ourselves this morning, driving down the Promenade des Anglais on our way out of Nice, something that dreams are made off. Herman has always said that he would not drive in Paris or Rome but the traffic that we have found ourselves in lately would be at least as bad as those places. The drive to Millau was made a little more interesting as it is part of the road that leads between Rome and Barcelona. Last night they had a football final in Rome and Manchester was pitted against Barcelona---Barcelona won! It seems that most of Barcelona had shipped themselves out by bus to Rome and they were all on their way home this morning. For them to have reached Nice already the busses must have been driving all night—Flags were flying and Horns were tooting. For a while we thought that Tom-Tom has set us on the wrong road and that soon we would be seeing the spectacular buildings of Barcelona but after about 300k we turned north and eventually we arrived in Millau.
The town of Millau is a charming little town; it has an ‘old centre’ where Herman and I have already gotten lost and it is situated in a bend of the Tarn River but the reason we are here is because of the bridge.
The Millau Viaduct is of special interest to us for we have watched the documentary on its construction on TV (twice). It is an engineering wonder of this century and it is another example of how clever some people can be. At 2.4km long, and 270m above the river at its highest point, the Millau viaduct spans a 2km valley in the Massif Central mountain range and forms the final link in the A75 highway from Paris to Barcelona. Despite its huge length, journey time over the structure is expected to be just one minute. The reason it was built was because of the traffic jams, especially around holiday time when that traffic was making life unliveable in the Tarn Valley because of the air pollution. When it opened in December 2004, the spectacular Millau Viaduct set new standards in both planning design and construction - without mentioning the record it set as the largest cable-stayed bridge in Europe. A point of interest that the company that built the Viaduct, the Eiffage Group, is also the company that built the Eiffel Tower
Here is some key data for anyone who is interested
Structural type:- Cable-stayed bridge multi-cable, fan arrangement
Function:- Highway bridge to carry the A75
Location:- Near Millau, Aveyron, France
Timescale:- Works started in October 2001 and was completed in December 2004
Cost:- €400 million
Earth moving:- 300,000m³
Number of workers on site:- 350-480
The interesting point for me is that they started building the bridge from both sides of the valley. The bridge crosses the Tarn valley at its lowest point, linking the causse du Larzac to the causse rouge. The bridge is within the perimeter of the Grands Causses regional natural park. Both sides start at different heights, the bridge also has a bend and a twist in the middle and they cantilevered the bridge out from both mountain tops. They made huge metal oblong boxes off site, carried them on huge trucks to the construction site, welded them together then pushed them out over the valley. You can imaging pushing something so heavy out into fresh air that it will sag and when it reaches a pier it would just push the pier over, the clever people invented hydraulic ramms that they installed on top of each pylon that lifted and pushed out at the same time but each set of hydraulics had to work simultaneously. That is how the bridge was pushed out at 600mm every 4 minutes. All went well until the tracks on one of the Hydraulic Ramms wore out and bad weather was coming in, if the Mistral winds that they suffer from in this area whipped around the unsecured bridge ends all would end up on the valley floor. The result was that they had to get the new set of hydraulics from a pylon that was not in use yet and on the work went. During all this time even the top engineer had his fingers crossed that the bridge would actually meet in the centre for if it was too much out of sync. all would be lost. When the two halves finally met where they were supposed to, they found that they were only one centimetre out and one of the things that aided in getting that result is that they had hung a GPS at the ends of both sections.