Thursday, July 31, 2008

Eiffel Tower

The Eiffel Tower is an iron tower built on the Champ de Mars beside the Seine River in Paris. The tower has become a global icon of France and is one of the most recognizable structures in the world.

Introduction>>
Named after its designer, engineer Gustave Eiffel, the Eiffel Tower is the tallest building in Paris and one of the most recognized structures in the world. More than 200,000,000 have visited the tower since its construction in 1889, including 6,719,200 in 2006, making it the most visited paid monument in the world. Including the 24 m (79 ft) antenna, the structure is 325 m (1,063 ft) high (since 2000), which is equivalent to about 81 levels in a conventional building.

Eiffel Tower October 2007
When the tower was completed in 1889 it was the world's tallest tower — a title it retained until 1930 when New York City's Chrysler Building (319 m — 1,047 ft tall) was completed. The tower is now the fifth-tallest structure in France and the tallest structure in Paris, with the second-tallest being the Tour Montparnasse (210 m — 689 ft), although that will soon be surpassed by Tour AXA (225.11 m — 738.36 ft).

Eiffel Tower from the neighborhood.
The metal structure of the Eiffel Tower weighs 7,300 tonnes while the entire structure including non-metal components is approximately 10,000 tonnes. Depending on the ambient temperature, the top of the tower may shift away from the sun by up to 18 cm (7 in) because of thermal expansion of the metal on the side facing the sun. The tower also sways 6–7 cm (2–3 in) in the wind. As demonstration of the economy of design, if the 7300 tonnes of the metal structure were melted down it would fill the 125 meter square base to a depth of only 6 cm (2.36 in), assuming a density of the metal to be 7.8 tonnes per cubic meter. The tower has a mass less than the mass of the air contained in a cylinder of the same dimensions, that is 324 meters high and 88.3 meters in radius. The weight of the tower is 10,100 tonnes compared to 10,265 tonnes of air.
The first and second levels are accessible by stairways and lifts. A ticket booth at the south tower base sells tickets to access the stairs which begin at that location. At the first platform the stairs continue up from the east tower and the third level summit is only accessible by lift. From the first or second platform the stairs are open for anyone to ascend or descend regardless of whether they have purchased a lift ticket or stair ticket. The actual count of stairs includes 9 steps to the ticket booth at the base, 328 steps to the first level, 340 steps to the second level and 18 steps to the lift platform on the second level. When exiting the lift at the third level there are 15 more steps to ascend to the upper observation platform. The step count is printed periodically on the side of the stairs to give an indication of progress of ascent. The majority of the ascent allows for an unhindered view of the area directly beneath and around the tower although some short stretches of the stairway are enclosed.
Maintenance of the tower includes applying 50 to 60 tonnes of paint every seven years to protect it from rust. In order to maintain a uniform appearance to an observer on the ground, three separate colors of paint are used on the tower, with the darkest on the bottom and the lightest at the top. On occasion the colour of the paint is changed; the tower is currently painted a shade of brownish-grey. On the first floor there are interactive consoles hosting a poll for the colour to use for a future session of painting. The co-architects of the Eiffel Tower are Emile Nouguier, Maurice Koechlin and Stephen Sauvestre.

Shape of the tower>>
Looking up at the Eiffel Tower.At the time the tower was built many people were shocked by its daring shape. Eiffel was criticised for the design and accused of trying to create something artistic, or inartistic according to the viewer, without regard to engineering. Eiffel and his engineers, as renowned bridge builders however, understood the importance of wind forces and knew that if they were going to build the tallest structure in the world they had to be certain it would withstand the wind. In an interview reported in the newspaper Le Temps, Eiffel said:
“now to what phenomenon did I give primary concern in designing the Tower? It was wind resistance. Well then! I hold that the curvature of the monument's four outer edges, which is as mathematical calculation dictated it should be will give a great impression of strength and beauty, for it will reveal to the eyes of the observer the boldness of the design as a whole.The shape of the tower was therefore determined by mathematical calculation involving wind resistance. Several theories of this mathematical calculation have been proposed over the years, the most recent is a nonlinear integral differential equation based on counterbalancing the wind pressure on any point on the tower with the tension between the construction elements at that point. That shape is exponential. A careful plot of the tower curvature however, reveals two different exponentials, the lower section having a stronger resistance to wind forces.

Events>>
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Lightning strikes the Eiffel Tower on 3 June 1902, at 9:20 P.M
The Eiffel Tower served as an advertising space for Citroën from 1925 to 1934.On September 10, 1889, Thomas Edison visited the tower. He signed the guestbook with the following message To M Eiffel the Engineer the brave builder of so gigantic and original specimen of modern Engineering from one who has the greatest respect and admiration for all Engineers including the Great Engineer the Bon Dieu, Thomas Edison.
Father Theodor Wulf in 1910 took observations of radiant energy radiating at the top and bottom of the tower, discovering at the top more than was expected, and thereby detecting what are today known as cosmic rays.On February 4, 1912, Austrian tailor Franz Reichelt died after jumping 60 metres from the first deck of Eiffel tower with his home-made parachute.
In 1925, the con artist Victor Lustig "sold" the tower for scrap metal.
In 1930, the tower lost the title of the world's tallest structure when the Chrysler Building was completed in New York City.
From 1925 to 1934, illuminated signs for Citroën adorned three of the tower's four sides, making it the tallest advertising space in the world at the time.
Upon the Nazi occupation of Paris in 1940, the lift cables were cut by the French so that Adolf Hitler would have to climb the steps to the summit. The parts to repair them were allegedly impossible to obtain because of the war. In 1940 German soldiers had to climb to the top to hoist the swastika, but the flag was so large it blew away just a few hours later, and it was replaced by a smaller one. When visiting Paris, Hitler chose to stay on the ground. It was said that Hitler conquered France, but did not conquer the Eiffel Tower. A Frenchman scaled the tower during the German occupation to hang the French flag. In August 1944, when the Allies were nearing Paris, Hitler ordered General Dietrich von Choltitz, the military governor of Paris, to demolish the tower along with the rest of the city. Von Choltitz disobeyed the order. The lifts of the Tower were working normally within hours of the Liberation of Paris.
On January 3, 1956, a fire damaged the top of the tower.
In 1957, the present radio antenna was added to the top.
In the 1980s, an old restaurant and its supporting iron scaffolding midway up the tower was dismantled; it was purchased and reconstructed on St. Charles Avenue in New Orleans, Louisiana, by entrepreneurs John Onorio and Daniel Bonnot, originally as the Tour Eiffel Restaurant, known more recently as the Red Room. The restaurant was re-assembled from 11,000 pieces that crossed the Atlantic in a 40-foot (12 m) cargo container.
On March 31, 1984, Robert Moriarty flew a Beechcraft Bonanza through the arches of the tower.
In 1985's James Bond action/adventure film A View to a Kill, Sir Roger Moore as James Bond chases May Day played by actress Grace Jones up the Eiffel Tower. She parachutes from the structure to escape. The video of the film's theme tune, performed by the group Duran Duran, also included several scenes of the band staged on the tower intercut with clips from the film. A full 20 years earlier, the Bond film Thunderball (1965) featured an establishing shot of the tower as the villainous Largo, played by Adolfo Celi, parks outside the headquarters of SPECTRE in Paris.
On July 14 1995, Bastille Day, French synthesiser musician Jean Michel Jarre performed Concert For Tolerance at the tower in aid of UNESCO. The free concert was attended by an estimated 1.5 million people, filling the Champ-de-Mars. The concert featured lighting and projection effects on the tower, and a huge firework display throughout. Exactly 3 years later, he returned to the same spot for a more dance music orientated show, Electronic Night.
On New Year's Eve 2000, the Eiffel Tower played host to Paris' Millennium Celebration. Fireworks exploded from the whole length of the tower in a spectacular display. An exhibition above a cafeteria on the first floor commemorates this event.
In 2000, flashing lights and four high-power searchlights were installed on the tower. Since then the light show has become a nightly event. The searchlights on top of the tower make it a beacon in Paris' night sky.
The tower received its 200,000,000th guest of all-time in 2002.
At 19:20 on July 22, 2003, a fire occurred at the top of the tower in the broadcasting equipment room. The entire tower was evacuated; the fire was extinguished after 40 minutes, and there were no reports of injuries.
Since 2004, the Eiffel Tower has hosted an ice skating rink on the first floor during the winter period.
At the start of the French Presidency of the European Union in the second half of 2008, the twelve golden stars of the European Flag were mounted on the base, and whole tower bathed in blue light.