The Eiffel Tower is an iron lattice tower located on the Champ de
Mars in Paris, named after the engineer Gustave Eiffel, whose company designed
and built the tower. Erected in 1889 as the entrance arch to the 1889 World's
Fair, it has become both a global cultural icon of France (the romantic city) and one of the most
recognizable structures in the world. The tower is the tallest structure in
Paris and the most-visited paid monument in the world; 7.1 million people
ascended it in 2011. The third level observatory's upper platform is at 279.11
m the highest accessible to public in the European Union and the
highest in Europe as long as the platform of the Ostankino Tower, at 360 m, remains closed as a result of the fire of August 2000. The tower
received its 250 millionth visitor in 2010.
The tower stands 300 metres tall, about the same height as an 81-storey building. During its construction,
the Eiffel Tower surpassed the Washington Monument to assume the title of the
tallest man-made structure in the world, a title it held for 41 years, until
the Chrysler Building in New York City was built in 1930. Because of the addition,
in 1957, of the antenna atop the Eiffel Tower, it is now taller than the
Chrysler Building. Not including broadcast antennas, it is the second-tallest
structure in France, after the Millau Viaduct.
The tower has three levels for visitors.
Tickets can be purchased to ascend, by stairs or lift (elevator), to the first
and second levels. The walk from ground level to the first level is over 300
steps, as is the walk from the first to the second level. The third and highest
level is accessible only by lift - stairs exist but they are not usually open
for public use. Both the first and second levels feature restaurants. The tower
has become the most prominent symbol of both Paris and France, often in the
establishing shot of films set in the city.
Construction
Work on the foundations started in January
1887. Those for the east and south legs were straightforward, each leg resting
on four 2 m concrete slabs, one for each of the principal girders of each leg
but the other two, being closer to the river Seine were more complicated: each
slab needed two piles installed by using compressed-air caissons 15 m long and 6 m in diameter driven to a depth of 22 m to support the concrete slabs, which were 6 m
thick. Each of these slabs supported a block built of limestone each with an
inclined top to bear a supporting shoe for the ironwork. Each shoe was anchored
into the stonework by a pair of bolts 10 cm in diameter and 7.5 m long. The foundations were complete by 30 June
and the erection of the ironwork began. The very visible work on-site was
complemented by the enormous amount of exacting preparatory work that was
entailed: 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 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 the factory in the nearby Parisian suburb of Levallois-Perret and were
first bolted together, the bolts being replaced by 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 there were 18,038 pieces
joined by two and a half million rivets.
At first the legs were constructed as
cantilevers but about halfway to the first level construction was paused in
order to construct a substantial timber scaffold. This caused a renewal of the
concerns about the structural soundness of the project, and sensational
headlines such as "Eiffel Suicide!" and "Gustave Eiffel has gone
mad: he has been confined in an Asylum" appeared in the popular press. At
this stage a small "creeper" crane was installed in each leg,
designed to move up the tower as construction progressed and making use of the
guides for the lifts which were to be fitted in each leg. The critical stage of
joining the four legs at the first level was complete by March 1888. Although
the metalwork had been prepared with the utmost precision, 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, each capable
of exerting a force of 800 tonnes, and in addition the legs had been
intentionally constructed at a slightly steeper angle than necessary, being
supported by sandboxes on the scaffold.
No more than three hundred workers were
employed on site, and because Eiffel took safety precautions, including the use
of movable stagings, guard-rails and screens, only one man died during
construction.
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