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.

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