Currier
& Ives print (1877)At the time
the bridge was built, the aerodynamics
of bridge building had not been worked
out. Bridges were not tested in wind
tunnels until the 1950s - well after
the collapse of the Tacoma Narrows
Bridge in the 1940s. It is therefore
fortunate that the open truss structure
supporting the deck is by its nature
less subject to aerodynamic problems.
Roebling designed a bridge and truss
system that was six times as strong
as he thought it needed to be. Because
of this, the Brooklyn Bridge is still
standing when many of the bridges
built around the same time have vanished
into history and have been replaced.
This is also in spite of the nefarious
substitution of inferior quality wire
in the cabling supplied by the contractor
J. Lloyd Haigh - by the time it was
discovered, it was too late to replace
the cabling that had already been
constructed. Roebling determined that
the poorer wire would leave the bridge
four rather than six times as strong
as necessary, so it was eventually
allowed to stand, with the addition
of 250 cables.
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