Eiffel Tower: Commemorating 137 Years of History
The Eiffel Tower was built for the 1889 World’s Fair, which celebrated the centenary of the French Revolution. This initially challenging and controversial project would later become an essential component of Paris’s monumental landscape and a symbol of the French capital around the world.
The concept for the Eiffel Pyramid was originally conceived in response to a competition announced in the Official Journal for the 1886 World’s Fair. This competition called for the construction of a square iron tower, 300 meters high and 125 meters long. Of the 107 projects submitted, the one designed by Gustave Eiffel , Maurice Kœchlin, and Emile Nouguier was selected.
Photo: René Gabriel Ojéda / Rmn – Grand Palais (Orsay Museum)
Construction of the Eiffel Pyramid began on January 26, 1887, lasting two years, two months, and five days, with the participation of approximately 300 workers, including 50 engineers and designers.
Photo: Tallandier / Bridgeman / ACI
The initial height of this structure was 300 meters, establishing itself as the tallest structure in the world at the time. An antenna was later added to its summit, reaching a final height of 324 meters.
Photo: Bnf / Rmn – Grand Palais
Photo: Patrice Schmidt / Rmn- Grand Palais (Orsay Museum)
The Eiffel Tower features a square platform with sides measuring 125 meters, its feet resting on concrete foundations, built a few meters below ground level on a layer of compacted gravel.
Photo: Patrice Schmidt / Rmn- Grand Palais (Orsay Museum)
It has 2.5 million rivets, about half of which are emergency rivets, as some feared the structure could collapse. This famous iron monument attracts more than 7 million visitors annually.
Photo: Louis-Emile Durandelle / Orsay Museum, Paris
The stability of this structure lies in the complexity of preventing the length of the uprights and beams from changing due to the lateral forces of the wind. In relief: This axonometric view shows the base of one of the tower’s pillars, formed by four hollow tubular uprights and tubular truss beams in a cross and zigzag pattern. The summit: the third floor is at a height of 276 m. Above it is a campanile with a beacon and crowned by a flag that flew at exactly 312.27 meters.
Photo: taschen.com
The arch located under the first floor has a purely decorative function and was not included in the first project by engineers Koechlin and Nouguier.
Photo: taschen.com
The plans of the Eiffel Tower
Source: toureiffel.paris
The design of the Eiffel Tower was the result of detailed analyses by some 40 engineers and draftsmen, who produced 700 assembly plans and 3,600 workshop drawings. The engineers’ primary concern was to prevent the tower from toppling over, which was achieved by the bell-shaped design of its four pillars, which provided sufficient stability. Thus, the tower’s 7,341-ton weight was firmly grounded. The second concern was to prevent excessive deformation (or swaying) due to wind forces, which required a highly rigid structure. This was achieved through two means: connecting the four main pillars by a long truss girder at the height of the first floor and implementing the triangulation system.
The fundamental structural unit of the Eiffel Tower is the triangulated quadrilateral. Each of the tower’s four pillars is composed of 28 of these quadrilaterals or panels, measuring between 6 and 11 meters on each side; in the span up to the first floor, at a height of 57.63 meters, there are four. This system ensures the tower’s almost complete stability against wind. The maximum horizontal oscillation at the top is 7 centimeters, which represents a ratio of 1/4285 to the height, much lower than the usual ratio for tall buildings, which is generally above 1/1000.
