World's Tallest Bridge

When it opened on 17 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.

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 road has two lanes in each direction and cost €400 million. This will be recouped by the builder, Eiffage, under a 75-year concession.

Bridge design

Two major challenges were identified in building the structure: crossing the River Tarn, and spanning the huge gap from one plateau to the other. The solution proposed is unique, using seven pylons instead of the typical two or three. It is several metres taller than that other famous French landmark, the Eiffel Tower.

Famous British architect Norman Foster was in charge of the viaduct's appearance. It has been designed to look as delicate and transparent as possible. Each of its sections spans 342m and its columns range in height from 75m to 235m over the river Tarn. It uses the minimum amount of material, which made it less costly to construct: the deck, the masts rising above the road deck and the multi-span cables are all in steel.

Seven Piers

The seven piers of the Millau Viaduct are sunk in shafts of reinforced concrete in a pyramidal shape, being divided in an overturned V, and the shrouds are anchored and distributed in semi harps. The program utilised hundreds of high-pressure hydraulic cylinders and pumps to push-launch the deck spans in place and a PC-synchronised lifting system to lift the auxiliary piers. Enerpac was awarded the major contract to supply the hydraulic system for lifting and pushing the bridge spans and piers for the bridge.

Intriguingly, the Millau Viaduct is not straight. A straight road could induce a sensation of floating for drivers, which a slight curve remedies. The curve is 20km in range. Moreover, the road has a light incline of 3% to improve the visibility and reassure the driver.

Bridge Construction

Construction began in October 2001, and by November the following year, the highest pier had already reached 100m in height. Launching the deck started in February 2003, and was completed by May 2004.

Unusually, the deck is constructed from a new high-grade steel as opposed to concrete. This helped the deck to be pre-constructed in 2,000 pieces at Eiffage's Alsace factory and GPS-aligned, 60cm at a time.

The Millau Viaduct is supported by multi-span cables placed in the middle. To accommodate the expansion and contraction of the concrete deck, there is 1m of empty space at its extremities and each column is split into two thinner, more flexible columns below the roadway, forming an A-frame above the deck level.

Construction work used approx. 127,000m³ of concrete, 19,000t of steel-reinforced concrete and 5,000t of pre-constraint steel (cables and shrouds). The project needed 205,000t of concrete, of which 50,000m³ will be reinforced concrete. In total, the viaduct weighs 290,000t.

A 3m-wide emergency lane provides increased security. It will, in particular, prevent drivers from seeing the valley from the viaduct.

As the bridge will be exposed to winds of up to 151km/hr, side screens are used to reduce the effects of the wind by 50%. The speed of the wind at the level of the road therefore reflects the speed of the wind found at ground level around Larzac and Sauveterre.

Toll Station

An 18-lane toll station 6km north of the Millau Viaduct is housed under a structure made of a special concrete patented by the group Eiffage. The toll plaza includes a CCTV connection to the viaduct and the highway. It also accommodates technical and administrative services.

The Palm And The World Islands In Dubai

The Palms Islands and the World Islands are the largest artificial islands in the world. Both developments are located in Dubai and are visible from space.

[Ed. Note: Here is my next post on Dubai: Teaching in Dubai.]

These two megastructures aren’t as grandiose as the megastructures in science-fiction, but they are being built in real life, which is even more impressive. I think of them as partial megastructures or megastructural, because at the end of the day, they are artificial islands. But then again, this is a first step into building real megastructures, so maybe they are the precursors to those structures in fiction. Technically, since they are visible from space, they are impressive.

What I find interesting is that these developments are built for the ultra rich. The World Islands retail at 15-45 million USD each. However, most have been bought by real estate developers to use in different ways, from ultra exclusive resorts I recently watched. There is one called OQYANA, trying to draw a parallel to Oceania, since it is located on the Australia and New Zealand World Islands. The name actually comes from the Arabic word for Oceanic (متعلق بالمحيط).

Richard Branson, Vijay Singh, Tommy Lee, Michael Schumacher, Rod Stewart and David Beckham have all been unofficially linked with purchases, but the main investors are all corporate.

In my mind, the World Island will always remain the giant floating world turtle in American Indian myths.

The Palm Islands in Dubai are the three largest artificial islands in the world. They are being constructed by Nakheel Properties, a property developer in the United Arab Emirates, who hired the Dutch dredging and marine contractor Van Oord, one of the world’s specialists in land reclamation. The islands are The Palm Jumeirah, The Palm Jebel Ali and The Palm Deira.

The islands were commissioned by Sheikh Mohammed bin Rashid Al Maktoum in order to increase Dubai’s tourism. Each settlement will be in the shape of a palm tree, topped with a crescent, and will have a large number of residential, leisure and entertainment centers. The Palm Islands are located off the coast of The United Arab Emirates in the Persian Gulf and will add 520 km of beaches to the city of Dubai.

The first two islands will comprise approximately 100 million cubic meters of rock and sand. Palm Deira will be composed of approximately 1 billion cubic meters of rock and sand. All materials will be quarried in the UAE. Between the three islands there will be over 100 luxury hotels, exclusive residential beach side villas and apartments, marinas, water theme parks, restaurants, shopping malls, sports facilities and health spas.

The creation of The Palm Jumeirah began in June 2001. Shortly after, The Palm Jebel Ali was announced and reclamation work began. In 2004, The Palm Deira, which will be almost as large in size as Paris, was announced. Palm Jumeirah is currently open for development. Construction will be completed over the next 10-15 years.

The World

The World is a man-made archipelago of 300 islands in the shape of a world map currently being built off the coast of Dubai, United Arab Emirates. The World is one of a series of artificial island projects in Dubai, along with the Palm Islands, and like the other islands The World is being built primarily using sand dredged from the sea. The World is the brainchild of Sheikh Mohammed bin Rashid Al Maktoum, ruler of Dubai.

Each island ranges from 23,000 m² to 84,000 m² (250,000–900,000 square feet or 5.7–21 acres) in size, with 50–100 m of water between each island. The development will cover an area of 9 km in length and 6 km in width, surrounded by an oval breakwater. The only means of transport between the islands will be by boat and helicopter. Prices for the islands will range from $15-45 million (USD). The average price for an island will be around $25 million (USD). Dredging started in 2004 and as of March of 2007 The World is around 90% complete.

According to the National Geographic Channel (The Best of Megastructures) the overall price for the World is $14 Billion US Dollars.

It is owned and is being constructed by Nakheel Properties (Nakheel Corp.)

It will be located 4.1 km off the shore of Jumeirah, close to Palm Jumeirah, between Burj Al Arab and Port Rashid of Dubai, United Arab Emirates.

The World is sometimes mistakenly referred to as The Palm World. It is also known as the Globe Islands.

3D Megastructures in Google Earth

ZNO blog has added some superb 3D models of several of the world’s megastructures, both existing and proposed; including the Burj Dubai, the Shard, London Bridge, UK, and the Millau Viaduct in France:

Supertalls and Megastructures

As society and technology continues to advance on an exponential scale, it is no wonder that structures are being classified into categories extreme as "supertalls" and "megastructures". These two categories are reserved for the world's largest, tallest, and most grand structures. The terms "Supertall" and "Megastructure" are jargon coined by skyscraper enthusiasts around the world with generally agreed upon terms. Supertalls and megastructures are often so celebrated because of the economics involved in making such structures possible

Supertall

Although an official definition does not exist, a supertall is generally a completed structure that is at least 300 meters or 1000 feet tall. If a building is being proposed, it must be at least 1 kilometer tall to be classified as a supertall.

The term supertall may be applied to any structure, including buildings, free standing towers, guyed masts, and bridge pillars.

There are about 1,150 supertalls worldwide, most of which are guyed masts in the United States.

Megastructures

Megastructures are usually only visions or science fiction due to their enormous proportions. A megastructure should have at least one dimension that is several hundred kilometers. Popularized in the 1960's, megastructures also including the concept of an encased city within a single building, often referred to as a hyperstructure.

There are only a few structures built that are considered megastructures:

• Great Wall of China
• Rice Terraces of the Philippine Cordilleras.

Roads or railways are not usually considered megastructures because of their relative simplicity.