The Eiffel Tower

(/ˈaɪfəl ˈtaʊər/ EYE-fəl TOWR; French: Tour Eiffel, pronounced: [tuʁ‿ɛfɛl] About this sound listen) 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.

History

Origin

The design of the Eiffel Tower was the product of Maurice Koechlin and Émile Nouguier, two senior engineers working for the Compagnie des Établissements Eiffel, after discussion about a suitable centrepiece for the proposed 1889 Exposition Universelle, a world's fair to celebrate the centennial of the French Revolution. Eiffel openly acknowledged that inspiration for a tower came from the Latting Observatory built in New York City in 1853. In May 1884, working at home, Koechlin made a sketch of their idea, described by him as "a great pylon, consisting of four lattice girders standing apart at the base and coming together at the top, joined together by metal trusses at regular intervals". Eiffel initially showed little enthusiasm, but he did approve further study, and the two engineers then asked Stephen Sauvestre, the head of company's architectural department, to contribute to the design. Sauvestre added decorative arches to the base of the tower, a glass pavilion to the first level, and other embellishments.

The new version gained Eiffel's support: he bought the rights to the patent on the design which Koechlin, Nougier, and Sauvestre had taken out, and the design was exhibited at the Exhibition of Decorative Arts in the autumn of 1884 under the company name. On 30 March 1885, Eiffel presented his plans to the Société des Ingénieurs Civils; after discussing the technical problems and emphasising the practical uses of the tower, he finished his talk by saying the tower would symbolise.

Not only the art of the modern engineer, but also the century of Industry and Science in which we are living, and for which the way was prepared by the great scientific movement of the eighteenth century and by the Revolution of 1789, to which this monument will be built as an expression of France's gratitude.

Little progress was made until 1886, when Jules Grévy was re-elected as president of France and Édouard Lockroy was appointed as minister for trade. A budget for the exposition was passed and, on 1 May, Lockroy announced an alteration to the terms of the open competition being held for a centrepiece to the exposition, which effectively made the selection of Eiffel's design a foregone conclusion, as entries had to include a study for a 300 m (980 ft) four-sided metal tower on the Champ de Mars. On 12 May, a commission was set up to examine Eiffel's scheme and its rivals, which, a month later, decided that all the proposals except Eiffel's were either impractical or lacking in details.

After some debate about the exact location of the tower, a contract was signed on 8 January 1887. This was signed by Eiffel acting in his own capacity rather than as the representative of his company, and granted him 1.5 million francs toward the construction costs: less than a quarter of the estimated 6.5 million francs. Eiffel was to receive all income from the commercial exploitation of the tower during the exhibition and for the next 20 years. He later established a separate company to manage the tower, putting up half the necessary capital himself.

Construction

Work on the foundations started on 28 January 1887. Those for the east and south legs were straightforward, with each leg resting on four 2 m (6.6 ft) concrete slabs, one for each of the principal girders of each leg. The west and north legs, being closer to the river Seine, were more complicated: each slab needed two piles installed by using compressed-air caissons 15 m (49 ft) long and 6 m (20 ft) in diameter driven to a depth of 22 m (72 ft) to support the concrete slabs, which were 6 m (20 ft) thick. Each of these slabs supported a block of limestone with an inclined top to bear a supporting shoe for the ironwork.

Each shoe was anchored to the stonework by a pair of bolts 10 cm (4 in) in diameter and 7.5 m (25 ft) long. The foundations were completed on 30 June, and the erection of the ironwork began. The visible work on-site was complemented by the enormous amount of exacting preparatory work that took place behind the scenes: the drawing office produced 1,700 general drawings and 3,629 detailed drawings of the 18,038 different parts needed. The task of drawing the components was complicated by the complex angles involved in the design and the degree of precision required: the position of rivet holes was specified to within 0.1 mm (0.0039 in) and angles worked out to one second of arc. The finished components, some already riveted together into sub-assemblies, arrived on horse-drawn carts from a factory in the nearby Parisian suburb of Levallois-Perret and were first bolted together, with the bolts being replaced with rivets as construction progressed. No drilling or shaping was done on site: if any part did not fit, it was sent back to the factory for alteration. In all, 18,038 pieces were joined together using 2.5 million rivets.

At first the legs were constructed as cantilevers, but about halfway to the first level, construction was paused in order to create a substantial timber scaffold. This renewed concerns about the structural integrity of the tower, and sensational headlines such as "Eiffel Suicide!" and "Gustave Eiffel Has Gone Mad: He Has Been Confined in an Asylum" appeared in the tabloid press. At this stage, a small "creeper" crane designed to move up the tower was installed in each leg. They made use of the guides for the lifts which were to be fitted in the four legs. The critical stage of joining the legs at the first level was completed by the end of March 1888. Although the metalwork had been prepared with the utmost attention to detail, provision had been made to carry out small adjustments in order to precisely align the legs; hydraulic jacks were fitted to the shoes at the base of each leg, capable of exerting a force of 800 tonnes, and the legs were intentionally constructed at a slightly steeper angle than necessary, being supported by sandboxes on the scaffold. Although construction involved 300 on-site employees, only one person died thanks to Eiffel's stringent safety precautions and the use of movable gangways, guardrails and screens.

Lifts

Equipping the tower with adequate and safe passenger lifts was a major concern of the government commission overseeing the Exposition. Although some visitors could be expected to climb to the first level, or even the second, lifts clearly had to be the main means of ascent.

Constructing lifts to reach the first level was relatively straightforward: the legs were wide enough at the bottom and so nearly straight that they could contain a straight track, and a contract was given to the French company Roux, Combaluzier & Lepape for two lifts to be fitted in the east and west legs. Roux, Combaluzier & Lepape used a pair of endless chains with rigid, articulated links to which the car was attached. Lead weights on some links of the upper or return sections of the chains counterbalanced most of the car's weight. The car was pushed up from below, not pulled up from above: to prevent the chain buckling, it was enclosed in a conduit. At the bottom of the run, the chains passed around 3.9 m (12 ft 10 in) diameter sprockets. Smaller sprockets at the top guided the chains.

Installing lifts to the second level was more of a challenge because a straight track was impossible. No French company wanted to undertake the work. The European branch of Otis Brothers & Company submitted a proposal but this was rejected: the fair's charter ruled out the use of any foreign material in the construction of the tower. The deadline for bids was extended but still no French companies put themselves forward, and eventually the contract was given to Otis in July 1887. Otis were confident they would eventually be given the contract and had already started creating designs.

The car was divided into two superimposed compartments, each holding 25 passengers, with the lift operator occupying an exterior platform on the first level. Motive power was provided by an inclined hydraulic ram 12.67 m (41 ft 7 in) long and 96.5 cm (38.0 in) in diameter in the tower leg with a stroke of 10.83 m (35 ft 6 in): this moved a carriage carrying six sheaves. Five fixed sheaves were mounted higher up the leg, producing an arrangement similar to a block and tackle but acting in reverse, multiplying the stroke of the piston rather than the force generated. The hydraulic pressure in the driving cylinder was produced by a large open reservoir on the second level. After being exhausted from the cylinder, the water was pumped back up to the reservoir by two pumps in the machinery room at the base of the south leg. This reservoir also provided power to the lifts to the first level.

The original lifts for the journey between the second and third levels were supplied by Léon Edoux. A pair of 81 m (266 ft) hydraulic rams were mounted on the second level, reaching nearly halfway up to the third level. One lift car was mounted on top of these rams: cables ran from the top of this car up to sheaves on the third level and back down to a second car. Each car only travelled half the distance between the second and third levels and passengers were required to change lifts halfway by means of a short gangway. The 10-ton cars each held 65 passengers.

Design

Material

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 considerations

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.

Accommodation

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.

Engraved names

Gustave Eiffel engraved on the tower the names of 72 French scientists, engineers and mathematicians in recognition of their contributions to the building of the tower. Eiffel chose this "invocation of science" because of his concern over the artists' protest. At the beginning of the 20th century, the engravings were painted over, but they were restored in 1986–87 by the Société Nouvelle d'exploitation de la Tour Eiffel, a company operating the tower.

Aesthetics

The tower is painted in three shades: lighter at the top, getting progressively darker towards the bottom to perfectly complement the Parisian sky. It was originally reddish brown; this changed in 1968 to a bronze colour known as "Eiffel Tower Brown".

The only non-structural elements are the four decorative grill-work arches, added in Sauvestre's sketches, which served to make the tower look more substantial and to make a more impressive entrance to the exposition.

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 seven storeys, only a small number of tall buildings have a clear view of the tower.

Maintenance

Maintenance of the tower includes applying 60 tons of paint every seven years to prevent it from rusting. The tower has been completely repainted at least 19 times since it was built. Lead paint was still being used as recently as 2001 when the practice was stopped out of concern for the environment.

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.

Replicas

As one of the most iconic landmarks in the world, the Eiffel Tower has been the inspiration for the creation of many replicas and similar towers. An early example is Blackpool Tower in England. The mayor of Blackpool, Sir John Bickerstaffe, was so impressed on seeing the Eiffel Tower at the 1889 exposition that he commissioned a similar tower to be built in his town. It opened in 1894 and is 158.1 metres (518 ft) tall. Tokyo Tower in Japan, built as a communications tower in 1958, was also inspired by the Eiffel Tower.

There are various scale models of the tower in the United States, including a half-scale version at the Paris Las Vegas, Nevada, one in Paris, Texas built in 1993, and two 1:3 scale models at Kings Island, Ohio, and Kings Dominion, Virginia, amusement parks opened in 1972 and 1975 respectively. Two 1:3 scale models can be found in China, one in Durango, Mexico that was donated by the local French community, and several across Europe.

In 2011, the TV show Pricing the Priceless on the National Geographic Channel speculated that a full-size replica of the tower would cost approximately US$480 million to build.

Illumination copyright

The tower and its image have long been in the public domain. In June 1990, however, a French court ruled that a special lighting display on the tower in 1989 to mark the tower's 100th anniversary was an "original visual creation" protected by copyright. The Court of Cassation, France's judicial court of last resort, upheld the ruling in March 1992. The Société d'Exploitation de la Tour Eiffel (SETE) now considers any illumination of the tower to be a separate work of art that falls under copyright. As a result, the SNTE alleges that it is illegal to publish contemporary photographs of the lit tower at night without permission in France and some other countries for commercial use.

The imposition of copyright has been controversial. The Director of Documentation for what was then called the Société Nouvelle d'exploitation de la Tour Eiffel (SNTE), Stéphane Dieu, commented in 2005: "It is really just a way to manage commercial use of the image, so that it isn't used in ways [of which] we don't approve". SNTE made over €1 million from copyright fees in 2002. However, it could also be used to restrict the publication of tourist photographs of the tower at night, as well as hindering non-profit and semi-commercial publication of images of the illuminated tower.

French doctrine and jurisprudence allows pictures incorporating a copyrighted work as long as their presence is incidental or accessory to the subject being represented, a reasoning akin to the de minimis rule. Therefore, SETE may be unable to claim copyright on photographs of Paris which happen to include the lit tower.

Source: WIKIPEDIA