The Tacoma bridge
On November 7, 1940, at approximately 11:00 AM, the first Tacoma Narrows
suspension bridge collapsed due to wind-induced vibrations. Situated on the
Tacoma Narrows in Puget Sound, near the city of Tacoma, Washington, the bridge had
only been open for traffic a few months.
There is a short
video
of the bridge just before break-down
(copyright owner
The Camera Shop).
There are also photo's available.
The twisting motion of the center span just prior to failure.
The nature and severity of the torsional movement is revealed in
this picture taken from the Tacoma end of the
suspension span. When the
twisting motion was at the maximum, elevation of the
sidewalk at the right
was 28 feet (8.5m) higher than the sidewalk at the left.
This photograph actually caught the first failure shortly before 11
o'clock, as the first concrete dropped out of the
roadway.
A few minutes after the first piece of concrete fell, this 600 foot
section broke out of the suspension span, turning
upside down as it crashed in Puget Sound.
Notice the car in the top right corner.
This photograph shows the sag in the east span after the failure.
With the centre span gone there was nothing to
counter balance the weight of
the side spans. The sag was 45 feet (13.7m). Also the
immense size of the anchorages is illustrated.
This picture was taken shortly after the failure.
Contact information:
Kees
Vuik
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of Kees Vuik.
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