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The Eiffel Tower, located at Paris, France, is one of the tallest towers in the world. Inaugurated on 31st March 1889 for the Universal French Exhibition in order to mark the French Revolution, the Eiffel Tower stands today as a civil engineering icon that is recognized and glorified around the world. With a length of 324 meters, the Eiffel Tower stood as the world’s tallest structure until 1930 when the Chrysler Building in New York City claimed the record.
The Eiffel Tower is completely a steel structure, weighing approximately ten thousand tones. The whole structure has been divided into three levels – first, second and third. The distance between ground and first and first and second is the almost the same and both these levels can be accessed both by stairways and elevators; however, the third level and the tower above it can be accessed only by elevators.
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The construction of the Eiffel Tower took place in between 1887 to 1889, during which around 300 workers worked simultaneously to join approximately 18,000 pieces of puddle iron. The construction team officially consisted of contractor Gustana Eiffel and Cie, engineers Maurice Koechlin and Emile Nouguier, and architect Stephen Sauvestre. The Eiffel Tower is now 120 years old and consists of 2.5 million rivets. It also has a flagpole at the top.
The construction and designing of the tower were done keeping in mind the available equipment at that time. In order to construct such a highly tall tower, it was essential to implant four bases which were eighty meters apart from each other and meticulously placed in order to raise the four pillars at a slant and prop them up. The Eiffel Tower is made up of a base, which resembles a bar stool resting on four main pillars, joined and extended with a lighter platform at a lower level.
The other important aspect of the Eiffel Tower is the tower which is firmly attached at the top of the structure. An expert team of rivet workers used an exclusive method of construction, which involved joining the metal pieces by rivets. The process included each rivet to be first heated and then molded by using a hammer.
The uprights were placed on the concrete foundation that was placed few meters below the ground level. All the corner edges of the uprights were positioned to rest on each of their supporting blocks, which resulted in a pressure of three to four kg/square centimeters on each one of them. On the side which faces the river Seine, the constructers used caissons (watertight chambers used for construction under water) and forced compressed air in order to carry out work below the water level.
Twelve temporary wooden platforms, each having a height of thirty meters and four larger platforms of forty meters each were used for the construction process. Moreover, small-sized steam cranes were also placed on the tower for lifting the heavy metal bars. The use of hydraulic jacks allowed the workers to position the metal girders to the estimated level of one millimeter. On 7th December 1887 the workers started the task of joining the main beams up to the first level. These pieces were pushed up by steam cranes which could climb on their own using the tower runners, which were later to be used for the building’s lifts. In all, it took five months to construct the foundation and 21 months to join the metal bars. Because of the kind of means available, the duration taken to make the structure was quite incredible.
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The French company Roux Combaluzier Lepape provid ed the original machines for the west piers, using hydraulic chains and rollers. Otis provided elevators which helped the visitors climb the second floor in a spacious cabin. During 1989, a four ton service elevator was installed to prohibit the main elevators from being used extensively. This structure was renovated again in 1995 with new cabins and computer expertise from Schneider Creusot Loire.
The upper cabin is a huge space that can accommodate 110 passengers (maximum weight of eight tons). The cabin is rested midway between the 2nd and 3rd levels on the pistons of 2 hydraulic jacks set up in vertical position. The only demerit of this machinery system was the volume of the liquid and the usage of proportional antifreeze additives. However, the problem was improved late on by installation of two electrical sets of two counterbalanced cabins.
The Eiffel Tower is one of those few monuments which constantly undergo changes whether it is with reference to the colour or lighting effects, the pavilion, or the staircases. Owing to its continuous developments, it is not a surprise that it has made a record of 243,376,000 number of visitors as of December 31, 2008 and was also formerly made a part of the Seven Wonders of the World.