The Eiffel Tower is an iron lattice tower located in Paris. Built in 1889, it has become both a global icon of France and one of the most recognizable structures in the world. The tower is the tallest building in Paris and the most-visited paid monument in the world; millions of people ascend it every year. Named for its designer, engineer Gustave Eiffel, the tower was built as the entrance arch to the 1889 World's Fair.
The tower stands 324 metres (1,063 ft) tall, about the same height as an 81-storey building. The tower has become the most prominent symbol of both Paris and France, often in the establishing shot of films set in the city.
Making of Eiffel Tower
The 72 names on the Eiffel TowerGustave Eiffel engraved on the tower seventy-two names of French scientists, engineers and other notable people.
Design of the tower
MaterialThe pig iron structure of the Eiffel Tower weighs 7,300 tonnes while the entire structure, including non-metal components, is approximately 10,000 tonnes. As a demonstration of the economy of design, if the 7,300 tonnes of the metal structure were melted down it would fill the 125 metre square base to a depth of only 6 cm (2.36 in), assuming the density of the metal to be 7.8 tonnes per cubic metre. Depending on the ambient temperature, the top of the tower may shift away from the sun by up to 18 cm (7.1 in) because of thermal expansion of the metal on the side facing the sun.
Researchers have found that Eiffel used empirical and graphical methods accounting for the effects of wind rather than a specific mathematical formula. Careful examination of the tower shows a basically exponential shape; actually two different exponentials, the lower section overdesigned to ensure resistance to wind forces. Several mathematical explanations have been proposed over the years for the success of the design; the most recent is described as a nonlinear integral equation based on counterbalancing the wind pressure on any point on the tower with the tension between the construction elements at that point.As a demonstration of the tower's effectiveness in wind resistance, it sways only 6–7 cm (2–3 in) in the wind.
MaintenanceMaintenance of the tower includes applying 50 to 60 tonnes of paint every seven years to protect it from rust.
The Fives-Lille elevators from ground level to the first and second levels are operated by cables and pulleys driven by massive water-powered pistons.
The principle behind the elevators is similar to the operation of a block and tackle but in reverse. There are 14 similar sheaves mounted statically. Six wire ropes are rove back and forth between the sheaves such that each rope passes between the 2 sets of sheaves 7 times.
The original elevators from the second to the third floor were also of a water-powered hydraulic design supplied by Léon Edoux. A pair of 81 metre long hydraulic rams were mounted on the second level reaching nearly half way up to the third level. An elevator car was mounted on top of the rams. Ropes ran from the top of this car up to a sheave on the third level and back down to a second car.
The ten-ton cars held 65 passengers each or up to four tons.
The original elevators complete with their hydraulic mechanism were completely scrapped in 1982 after 97 years of service. They were replaced with two pairs of relatively standard rope hoisted cars which were able to operate all the year round.
Since the beginning of the 20th century, the tower has been used for radio transmission. Today, both radio and television stations broadcast their signals from the top of the Eiffel.