Higher, longer, wider: the art of building bridges

The Millau Viaduct is the latest example of one of mankind's noblest traditions: the creation of breathtaking structures to span hitherto unbridgeable divides. John Lichfield reports

The stunningly beautiful Millau Viaduct, opened by President Jacques Chirac yesterday, is a bridge to the future. Built in only three years, using construction and design techniques and materials which did not exist a decade ago, it is the highest and the heaviest bridge ever built.

Seen from a distance, and even from the foot of one of its colossal split, curving piers, it has a deceptive fragility.

The bridge, in the southern Massif Central, designed by the British architect Lord Foster, and constructed by French engineers, has pioneered techniques which will open the way to even bigger structures. The first may be a span across the straits of Messina from Calabria in southern Italy to Sicily.

Lord Foster and French engineers believe the Millau Viaduct - 2.4 km long (1.5 miles) and 270m (885 ft) above the river Tarn at its highest point, and several metres taller than the Eiffel Tower - will mark the beginning of a new era in mankind's 2,000-year-old love affair with bridge building.

Each age has seen the creation of new techniques which have made possible the bridging of seemingly unbridgeable chasms. One of the great bridges of ancient times - the Pont du Gard, near Nîmes - is only 70 miles away from Millau as the eagle flies. Its Roman builders pushed the discovery of the principle of the arch to daring new levels by piling three arched viaducts one on top of the other, to allow water to flow into the Roman city of Nîmes.

The discovery of steel and the bold, sweeping new application of the ancient principles of suspension bridges allowed the creation of the Menai road bridge and Tamar and Forth railway bridges in the 19th century and their bigger cousins at the Golden Gate in San Francisco and Sydney Harbour. Other famous bridges have been significant less for pushing back the frontiers of engineering than for the metaphorical divides they spanned. The world's great bridges have a value that is moral and aesthetic as much as mechanical.

In the Millau Viaduct, computer-design methods, global satellite positioning and high-tech steels and concretes have come together with an aesthetic overall plan conceived by an architect, not an engineer. The result is a bridge of enormous beauty, built in record time, for a relatively cheap €400m (£275m), entirely financed by private investment, which will be refunded by tolls over 75 years.

The gently curving deck of the bridge - on which the four-lane road rests - has been constructed from a new high grade of steel, rather than the more usual concrete.

The French construction company Eiffage devised a method for pre-constructing the 32m-wide road-deck in 2,000 pieces at its factory in Alsace. They were welded together on the hills on either side of the valley and then shoved out like giant planks over the abyss, 60cms at a time. Satellite positioning technology was used to ensure the curving road connected correctly.

Lord Foster says the choices that shaped the Millau bridge were practical but also aesthetic and even spiritual. "Infrastructure is fundamental to our civilisation. Public spaces, boulevards, bridges ... they connect people and shape our quality of life. But mankind also has more spiritual needs. Crossing a bridge should give you a sense of spiritual elevation. Looking at a bridge should be a moving experience."

President Chirac, while paying tribute to Lord Foster, yesterday saluted the Millau bridge as a tribute to a "modern France, a conquering France ... an entrepreneurial France, a France which succeeds" .

The Millau Viaduct will eventually be part of a new motorway route from Paris to the Languedoc coast and Barcelona. It will remove a bottle-neck around the town of Millau. But political arguments and bureaucratic delays mean the motorway links further south will not be completed until 2010 at the earliest.

Leading article, page 24

Golden Gate Bridge California

Not golden but "international orange", chief engineer Joseph B Strauss's 1937 Art Deco masterpiece defied the odds, the critics and the tides to link San Francisco to Marin County. Designed by Irving Morrow, it was acclaimed for its steel structure and its huge concrete anchorages. It took four years to build and used a safety net to catch falling workers during construction - innovative for the time.

Mostar Stari Most Bosnia

The destruction of the "stone crescent" infighting between Muslims and Croats in 1993 was one of the Balkan nightmare's darkest moments.

Commissioned in 1557, the bridge across the river Neretva was built in limestone to match the city's minarets. The first attempt collapsed but the second became one of the jewels of the Ottoman Empire. Reconstruction finished in July.

Allahverdi Khan Bridge Iran

Known as the Pearl of Islam, Shah Abbas the Great's crossing of the river Zayandeh established Isfahan, the heart of the Safavid empire, as one of the most important cities in the world in 1602. At 295m long, with 33 lower arches it became an early tourist marvel. The bridge was for animals and carts, paths were for pedestrians and arcaded galleries allowed citizens to congregate and contemplate.

Clifton Suspension Bridge Bristol

Isambard Kingdom Brunel's construction across the Avon Gorge was delayed by faltering finance and the completion of its 214m span took more than 30 years. The project was rescued after Brunel's death in 1859 by his colleagues at the Institution of Civil Engineers, using reclaimed chains from his demolished Hungerford Bridge. Clifton Bridge was finished in 1864.

Akashi Kaikyo Bridge Japan

While still under construction, it withstood the earthquake in 1995 that claimed the lives of 5,000 people in Kobe and left 27,000 injured. Its six-lane highway links Maiko in Kobe to Awaji Island. It has the longest central section of any suspension bridge in the world, but its builders - the Honshu-Shikoku Office of Bridge Construction - fought shy of building a 2km span for superstitious reasons.

Millau Viaduct France

At 343m (1,125 ft), it is taller than the Eiffel Tower; its span of 1.5 miles makes it longer then the Champs Elysées. Lord Foster's £276m viaduct over the Tarn Valley at Millau is designed to end the motorway logjam between Paris and the Spanish border.

Opening to traffic at midnight on Friday, the bridge is expected to carry 10,000 vehicles per day, peaking at 25,000 in the summer. It will form part of the A75 motorway in the Massif Central linking Clermont-Ferrand and Béziers.

Built and funded by Eiffage - the group responsible for the Eiffel Tower - and with a British architect, the bridge is being hailed as the heir to such Anglo-French triumphs as Concorde and the Channel tunnel. It became a tourist attraction almost as soon as work began. Motorists will pay a £3.50 toll.

Pont du Gard France

The purpose of this bridge-aqueduct, begun in pre-Christian times by order of the Roman consul Marcus Vipsanius Agrippa, son-in-law of the emperor Augustus, was to bring water from the river Eure to the city of Nîmes. It measures 275m (900ft) long and 49m (160ft) high. The three-tiered structure has undergone many renovations since its completion during the reign of Trajan (AD98-AD117). Stones removed in the Middle Ages were replaced in 1743 when a bridge was built next to the first tier. Since 1855, the aqueduct's walls and vaults have been consolidated and it was added to the Unesco World Heritage List in 1985. More than 1,250,000 tourists visit it each year.

Iron Bridge Shropshire

The world's first cast-iron bridge replaced the ferry across the river Severn near thriving Coalbrookdale during the Industrial Revolution. Designed by architect Thomas Pritchard,it took 17 weeks to bolt together in 1779. The ironmaster Abraham Darby III provided financial backing and his investment gave its name to the industrial town, Ironbridge, and generated many imitations.

Oresund Denmark/Sweden

This 10-mile road and rail link, the longest single span to carry both modes of transport, was completed in 2000, bringing Denmark and Sweden physically together for the first time since the Ice Age. Designed by George Rothne, it is the second longest suspension bridge in the world and its 203m pylons are the tallest structures in Sweden. The link passes over the artificial island of Pepparholm.

Forth Rail Bridge Firth of Forth

William Morris thought it was "the supremest specimen of all ugliness". Yet when John Fowler and Benjamin Baker's creation was completed in 1889, its 55,000 tons of steel set records, as did the height, length and depth of its cantilevers. It was built in the wake of the Tay Bridge collapse, which killed 75, and was designed to withstand wind loads 5.5 times that which destroyed the Tay.

Bosphorus Bridge Turkey

Attempts to build a permanent structure linking the Occident to the Orient defeated even Leonardo da Vinci, whose plan for a bridge from Constantinople to Pera was never realised. But the German engineering firm Hochtief AG and the British firm Freeman, Fox and Partners made it a reality in 1973. Tolls on the 1,074-ft structure financed a second bridge in 1988 and a third is planned.

Skye Bridge Kyle of Lochalsh

Opened in 1995, this bridge was resented by many islanders and rendered the ferry obsolete. Opponents call Scotland's first private finance initiative the most expensive and unjust toll bridge in Europe and a campaign of non-payment grew, although winter weather had often stopped the ferry. The Scottish Executive plans to buy back the concession for tolls; £5.70 for a car, £11.40 for a caravan.