Information
Location Paris, France
Status Complete
Constructed 1887 – 1889
Use Observation tower
Radio broadcasting tower
Height
Antenna/Spire 324 metres (1,063 ft)
Roof 300.65 metres (986 ft)
Companies
Architect Gustave Eiffel
Structural
Engineer Gustave Eiffel
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.[1] More than 200,000,000 have visited the tower since its construction in 1889,[2] including 6,719,200 in 2006,[3] making it the most visited paid monument in the world.[4][5] 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.
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.[6] 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).
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.[3] 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,[7] 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.[8] 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.[9]
History
The structure was built between 1887 and 1889 as the entrance arch for the Exposition Universelle, a World's Fair marking the centennial celebration of the French Revolution. Eiffel originally planned to build the tower in Barcelona, for the Universal Exposition of 1888, but those responsible at the Barcelona city hall thought it was a strange and expensive construction, which did not fit into the design of the city. After the refusal of the Consistory of Barcelona, Eiffel submitted his draft to those responsible for the Universal Exhibition in Paris, where he would build his tower a year later, in 1889. The tower was inaugurated on March 31, 1889, and opened on 6 May. Three hundred workers joined together 18,038 pieces of puddled iron (a very pure form of structural iron), using two and a half million rivets, in a structural design by Maurice Koechlin. The risk of accident was great, for unlike modern skyscrapers the tower is an open frame without any intermediate floors except the two platforms. However, because Eiffel took safety precautions, including the use of movable stagings, guard-rails and screens, only one man died.
The tower was met with much criticism from the public when it was built, with many calling it an eyesore. Newspapers of the day were filled with angry letters from the arts community of Paris. One is quoted extensively in William Watson's US Government Printing Office publication of 1892 Paris Universal Exposition: Civil Engineering, Public Works, and Architecture. “And during twenty years we shall see, stretching over the entire city, still thrilling with the genius of so many centuries, we shall see stretching out like a black blot the odious shadow of the odious column built up of riveted iron plates.”[10] Signers of this letter included Messonier, Gounod, Garnier, Gerome, Bougeureau, and Dumas.
Novelist Guy de Maupassant — who claimed to hate the tower — supposedly ate lunch in the Tower's restaurant every day. When asked why, he answered that it was the one place in Paris where you couldn't see the Tower. Today, it is widely considered to be a striking piece of structural art.
One of the great Hollywood movie clichés is that the view from a Parisian window always includes the tower. In reality, since zoning restrictions limit the height of most buildings in Paris to 7 stories, only a very few of the taller buildings have a clear view of the tower..
Eiffel had a permit for the tower to stand for 20 years, meaning it would have had to be dismantled in 1909, when its ownership would revert to the City of Paris. The City had planned to tear it down (part of the original contest rules for designing a tower was that it could be easily demolished) but as the tower proved valuable for communication purposes, it was allowed to remain after the expiration of the permit. The military used it to dispatch Parisian taxis to the front line during the First Battle of the Marne, and it therefore became a victory statue of that battle.
Shape of the 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 r
enowned 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.
Installations
Since the beginning of the 20th century, the tower has been used for radio transmission. Until the 1950s, an occasionally modified set of antenna wires ran from the summit to anchors on the Avenue de Suffren and Champ de Mars. They were connected to long-wave transmitters in small bunkers; in 1909, a permanent underground radio centre was built near the south pillar and still exists today.[citation needed] On November 20, 1913, the Paris Observatory, using the Eiffel Tower as an antenna, exchanged sustained wireless signals with the United States Naval Observatory which used an antenna in Arlington, Virginia. The object of the transmissions was to measure the difference in longitude between Paris and Washington, D.C.[14]
The tower has two restaurants: Altitude 95, on the first floor (95 m, 311 ft, above sea level); and the Jules Verne, an expensive gastronomical restaurant on the second floor, with a private lift. This restaurant has one star in the Michelin Red Guide. In January 2007, a new multi-Michelin star chef Alain Ducasse was brought in to run Jules Verne.[15]
The uppermost observation deck, with a height of 275 metres, is the highest area of an architectural structure in the European Union open for the public.[citation needed]
The passenger lifts from ground level to the first level are operated by cables and pulleys driven by massive water-powered pistons. As they ascend the inclined arc of the legs, the elevator cabins tilt slightly, but with a slight jolt every few seconds, in order to keep the floor nearly level.[citation needed] The elevator works are on display and open to the public in a small museum located in one of the four tower bases.
