State of Technology: The Highest Bridge in the World

Millau Bridge- Highest Bridge in the World

The Millau bridge over the River Tarn in the Massif Central mountains is more than 300m (984ft) high - taller even than the Eiffel Tower. With its concrete and steel pillars soaring high above the morning fog in the Tarn Valley, the construction makes a spectacular sight.

Info

Official name Le Viaduc de Millau

Crosses Valley of the River Tarn

Locale Millau-Creissels, France

Architect Michel Virlogeux

Design Cable-stayed bridge

Total length 2460 m

Width 32.05 m

Height 343 m (max pylon above ground)

Longest span 342 m

Number of spans 204 m, 6×342 m, 204 m

Clearance below 270 m (890 ft)

Construction begin 16 October, 2001

Construction cost € 394,000,000

Opened 16 December, 2004

Inaugurated 14 December 2001[1]

Coordinates 44°04′46″N 03°01′20″E

A complicated system of hydraulic rams was used to slide the vast bridge deck into place. It was provided by Enerpac Hydraulic Systems - the company which also "lifted" Golden Gate Bridge off its foundation for better cushioning against earthquakes. Here is a diagram of pushing the bridge's deck:

From both sides of the valley the metal sections of the bridge are assembled, lifted slightly and then in an elaborate manoeuvre pushed into place on each of the seven supporting pillars. The architect, Norman Foster, said the bridge was designed to have the "delicacy of a butterfly"

Statistics

2,460 m (8,071 ft): total length of the roadway

7: number of piers

77 m (253 ft): height of Pier 7, the shortest

343 m (1,125 ft): height of Pier 2, the tallest (245 m/804 ft at the roadway's level)

87 m (285 ft): height of a mast

154: number of shrouds

270 m (886 ft): average height of the roadway

4.20 m (13 ft 9 in): thickness of the roadway

32.05 m (105 ft 2 in): width of the roadway

85,000 m3 (111,000 cu yd): total volume of concrete used

290,000 metric tons (320,000 short tons): total weight of the bridge

10,000–25,000 vehicles: estimated daily traffic

€6.00–7.50: typical automobile toll, as of December 2009

20 km (12 mi): horizontal radius of curvature of the road deck

540 workers spent years working on just erecting the towers before they could begin assembling the roadway.

Often the bridge is over the clouds which hover in the valley below. Construction workers on the ground could not see what the people on top of the towers were doing beacuse of the great height and frequent cloud cover.

Darkness did not slow down the construction as workers labored at times around the clock to get the important roadway open.

Unfinished, the first sections stop at a few hundred feet out. Eventually the two sides met in the middle and were connected. Now that the bridge is complete a driver can save 100 kilometers and 4 hours of driving time by sailing over the valley below.