To make the project more acceptable to public opinion, Nugier and Kohlin
instructed the architect Stephen Sovestra to work on the appearance of the
project.
Co-investor proposed stone pedestals to ennoble the lower part, monumental
arches to connect the columns and the first level, large glass halls on each
level, bulbous design for the top and a variety of other decorative features
allowing to decorate the entire structure. As a result, the project was
simplified, but some elements, such as large arches at the base, were
preserved, which in part gives it a very distinctive look.
The curvature of the rack is mathematically determined to offer the most
effective resistance to wind. As Eifel himself explains: "All the cutting force of
the wind passes inside the front edge rack. The lines directed tangentially to
each vertical with the point of each tangent at one height will always intersect
at the second point, which is exactly the point through which the stream flows,
resulting from the effect of the wind on that part of the tower support located
above the two indicated points. "
The assembly of the support began on July 1, 1887, and was completed
twenty-two months later.
All elements were prepared at the Eifel factory, located in Levallois-Perret, on
the outskirts of Paris. Each of the 18,000 elements used to build the Tower was
specially designed and calculated, traced to the nearest tenth of a millimeter,
together, forming new pieces of five meters each. The
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3 assembled
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team of designers, who worked on large projects of metal viaducts, was
responsible for 150-300 workers at the site of the assembly of this giant set of
elements.
All metal parts of the tower are held together by rivets, a well-refined
construction method at a time when the tower was built. At first, the pieces
were assembled at the factory with bolts, which were then replaced one by one
with thermally assembled rivets that contracted during cooling, thus ensuring
a very tight fit. For each setting of one rivet, a team of four people was needed:
one to warm it, the other to hold it in place, the third to form the head and the
fourth to hammer it with a sledgehammer. Only a third of the 250,000 rivets
used in the construction of the Tower were inserted directly on site.
Support posts on concrete bases are set several meters below the ground level
The bet was to "study the possibility of installing an iron tower
on the Champ de Mars with a square base, 125 meters high and
300 meters high." The project of Gustav Eiffel, businessman
Maurice Kohlin and Emil Nugire, engineers and Stephen
Souverre, architect, who was selected from 107 applications.
Emil Nugier and Maurice Kehlin, two chief engineers at Eiffel,
had an idea for a very high tower in June 1884. It was to be
designed as a large pylon with four columns of lattice beams
separated at the base and assembled together at the top and
connected to each other by more metal beams at regular
intervals.
above the layer of compacted gravel. Each edge rests on its own support block,
applying pressure to it from 3 to 4 kilograms per square centimeter, and each
block is connected to the rest of the walls.
On the side of the Seine, construction workers used waterproof metal caissons
and squeezed compressed air so that they could operate below the water level.
The tower was assembled using wooden forests and small steam cranes
installed on the tower itself.
The first level was assembled by using twelve temporary wooden forests with a
height of 30 meters and four large forests of 40 meters each.