|
|
 |
 |
|
Brooklyn bridge
|
This bridge
was built between 1869 and 1883 by J.A Roebling
(who died during the construction) and his son W.
Roebling, and was strengthened in 1952. It joins
Brooklyn to Manhattan. Beforehand the crossing was
not possible when the ferry was blocked by ice.
.
This suspension bridge made of steel has 3 spans
(286,70-456,50-286,70 m long). The deck is 50 m
above sea level. The suspension cables have a 40
cm diameter. Inclined stays between
the towers and the deck, as on cable-stayed bridges,
improve the resistance of the bridge
against the wind.
For the construction of foundations, Roebling used
big decompression caissons in which tens of workers
were working to excavate. The air pressure necessary
to maintain the water out of the caisson caused
many cases of caisson disease which affected in
particular W. Roebling. Its two granite gothic towers
made the bridge world famous. They are 83 m high
and have been listed national monuments. They inspired
many artists.
The exceptional duration of the construction is
due to the gigantic proportion of the towers, the
length of the central span (the world record at
that time) and the width of the deck.
|
 |
|
 |
|
| |
|
