Thursday, September 29, 2016

Eiffel Tower Paris

                 Eiffel Tower Paris




 THE EIFFEL TOWER is a wrought iron lattice tower on the Champ de Mars in Paris, France. It is named after the engineer Gustave Eiffel, whose company designed and built the tower.

Constructed from 1887-89 as the entrance to the 1889 World's Fair, it was initially criticized by some of France's leading artists and intellectuals for its design, but it has become a global cultural icon of France and one of the most recognisable structures in the world. The Eiffel Tower is the most-visited paid monument in the world; 6.91 million people ascended it in 2015.

The tower is 324 metres (1,063 ft) tall, about the same height as an 81-storey building, and the tallest structure in Paris. Its base is square, measuring 125 metres (410 ft) on each side. During its construction, the Eiffel Tower surpassed the Washington Monument to become the tallest man-made structure in the world, a title it held for 41 years until the Chrysler Building in New York City was finished in 1930. Due to the addition of a broadcasting aerial at the top of the tower in 1957, it is now taller than the Chrysler Building by 5.2 metres (17 ft). Excluding transmitters, the Eiffel Tower is the second-tallest structure in France after the Millau Viaduct.

The tower has three levels for visitors, with restaurants on the first and second levels. The top level's upper platform is 276 m (906 ft) above the ground – the highest observation deck accessible to the public in the European Union. Tickets can be purchased to ascend by stairs or lift (elevator) to the first and second levels. The climb from ground level to the first level is over 300 steps, as is the climb from the first level to the second. Although there is a staircase to the top level, it is usually only accessible by lift.

Material Used For Designing the Tower


The puddled iron (wrought iron) of the Eiffel Tower weighs 7,300 tons, and the addition of lifts, shops and antennae have brought the total weight to approximately 10,100 tons. As a demonstration of the economy of design, if the 7,300 tons of metal in the structure were melted down, it would fill the square base, 125 metres (410 ft) on each side, to a depth of only 6.25 cm (2.46 in) assuming the density of the metal to be 7.8 tons per cubic metre. Additionally, a cubic box surrounding the tower (324 m x 125 m x 125 m) would contain 6,200 tons of air, weighing almost as much as the iron itself. Depending on the ambient temperature, the top of the tower may shift away from the sun by up to 18 cm (7 in) due to thermal expansion of the metal on the side facing the sun.

Wind Consideration For Designing The Tower

When it was built, many were shocked by the tower's daring form. Eiffel was accused of trying to create something artistic with no regard to the principles of engineering. However, Eiffel and his team – experienced bridge builders – 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 sure it could withstand them. In an interview with the newspaper Le Temps published on 14 February 1887, Eiffel said:

" Is it not true that the very conditions which give strength also conform to the hidden rules of harmony? … Now to what phenomenon did I have to 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. "

He used graphical methods to determine the strength of the tower and empirical evidence to account for the effects of wind, rather than a mathematical formula. Close examination of the tower reveals a basically exponential shape. All parts of the tower were over-designed to ensure maximum resistance to wind forces. The top half was even assumed to have no gaps in the latticework. In the years since it was completed, engineers have put forward various mathematical hypotheses in an attempt to explain the success of the design. The most recent, devised in 2004 after letters sent by Eiffel to the French Society of Civil Engineers in 1885 were translated into English, is described as a non-linear integral equation based on counteracting the wind pressure on any point of the tower with the tension between the construction elements at that point.


The Eiffel Tower sways by up to 9 centimetres (3.5 in) in the wind.

Accommodations


When originally built, the first level contained three restaurants—one French, one Russian and one Flemish—and an "Anglo-American Bar". After the exposition closed, the Flemish restaurant was converted to a 250-seat theatre. A promenade 2.6-metre (8 ft 6 in) wide ran around the outside of the first level. At the top, there were laboratories for various experiments, and a small apartment reserved for Gustave Eiffel to entertain guests, which is now open to the public, complete with period decorations and lifelike mannequins of Eiffel and some of his notable guests.

In May 2016, an apartment was created on the first level to accommodate four competition winners during the UEFA Euro 2016 football tournament in Paris in June. The apartment has a kitchen, two bedrooms, a lounge, and views of Paris landmarks including the Seine, the Sacre Coeur, and the Arc de Triomphe.

Passenger Lifts

The arrangement of the lifts has been changed several times during the tower's history. Given the elasticity of the cables and the time taken to align the cars with the landings, each lift, in normal service, takes an average of 8 minutes and 50 seconds to do the round trip, spending an average of 1 minute and 15 seconds at each level. The average journey time between levels is 1 minute. The original hydraulic mechanism is on public display in a small museum at the base of the east and west legs. Because the mechanism requires frequent lubrication and maintenance, public access is often restricted. The rope mechanism of the north tower can be seen as visitors exit the lift.

                       Tourism

Transport
The nearest Paris Métro station is Bir-Hakeim and the nearest RER station is Champ de Mars-Tour Eiffel. The tower itself is located at the intersection of the quai Branly and the Pont d'Iéna.

Popularity

More than 250 million people have visited the tower since it was completed in 1889. In 2015, there were 6.91 million visitors. The tower is the most-visited paid monument in the world. An average of 25,000 people ascend the tower every day which can result in long queues. Tickets can be purchased online to avoid the long queues.

Restaurants

The tower has two restaurants: Le 58 Tour Eiffel on the first level, and Le Jules Verne, a gourmet restaurant with its own lift on the second level. This restaurant has one star in the Michelin Red Guide. It is run by the multi-Michelin star chef Alain Ducasse and owes its name to the famous science-fiction writer Jules Verne.

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