The Eiffel Tower: How was it built?
The Eiffel Tower was the brainchild of French structural engineer Alexandre Gustave Eiffel, who proposed a 324m (986ft) tower for the capital’s Champ de Mars, costing the city $1.5 million, for its World’s Fair.
Work began in July 1887 and took just under two years to complete. To begin with the framework was pre-assembled in a factory and in total over 300 workers joined 18,000 pieces of puddle iron to produce parts of the frame. When the parts were ready they were transported to the Champ de Mars where welders secured each segment in place. As the tower grew, moveable platforms were propped into place on the intermediary levels, not only to enable the workforce to weld the latticework together but for their own safety.
The tower features exposed latticework and consists of two main parts; a 2.54-acre base which compromises a platform sitting upon four individual legs known as pylons or bents, and a tower created as the pylons incline towards each other, rising upwards past a second platform which then merges into one long column.
The shape of the tower was engineered using a mathematical calculation involving wind resistance. Eiffel reasoned that the tower had to counterbalance the wind pressure applied on any point by spreading the tension between the construction elements at that point. Therefore the tower’s curvature revealed two exponentials: a lower base section that delivers stronger resistance to wind forces, meaning the tower will only sway at a maximum of 6-7cm in the wind.
How the Eiffel Tower was built
1st floor (57m)
Work started on 26 January 1887, withthe foundations alone taking five months to build. Scaffolding was erected and the ‘feet’ were positioned with hydraulic jacks.
2nd floor (115m)
Floor two was assembled using cranes that took the same route as the elevators. All of the parts were riveted into position on site.
3rd floor (276m)
Carpenters set to work laying the third floor – with no fatal accidents during construction.
31 March 1889
On the tower’s inauguration Gustave Eiffel climbed to the top to plant the French flag.
The Eiffel Tower took just two years for 300 workers to complete and despite working on an open framework, and without the safety of intermediate floors, accidents were low and only one man died during construction. This is thought to have been due to the foresight of Eiffel who had insisted upon safety precautions in the form of moveable stagings, guard rails and screens.
In 1909, at the end of its 20 year lease the tower came under criticism as an eyesore, and was almost torn down. It was only saved because of its antenna, which was used for the city’s communications.
Eiffel Tower stats
Total weight: 10,100 tons
Cost: $1.5 million
Base area: 2.54 acres
Height: 324 metres
Rivets: 2.5 million
Steps to the top: 1,665
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