Farquharson continued wind tunnel tests. He concluded that the “cumulative effected of undampened rhythmic forces” had produced “intense resonant oscillation.” in other words, the bridge’s lightness, combined with an accumulation of wind pressure on the 8-foot solid plate girder and deck, caused the bridge to fail.
What Happen to the Tacoma Narrows Bridge?
The Tacoma Narrows Bridge is an iconic suspension bridge in Tacoma, Washington. Built-in 1940, the bridge was considered an engineering marvel for its innovative design and soaring views of the Puget Sound below. However, on November 7, 1940, the bridge was the site of a spectacular and catastrophic failure that still remains one of the most iconic engineering disasters of the 20th century.
On that fateful day, the bridge was struck by extreme gale-force winds traveling at more than 40 miles per hour. As a result, the bridge began to oscillate, or sway, back and forth, eventually tearing itself apart and throwing cars and debris into the sound below. The entire episode was filmed and is an often studied example in engineering classes.
The forces that caused the collapse of the first Tacoma Narrows Bridge resulted from a phenomenon known as aeroelastic flutter. This flutter occurs when the bridge experiences a resonance with the wind, creating an agitation that eventually causes structure failure. The bridge’s original design, with its singular support system, was especially susceptible to the effect of these oscillations, as there was little resistance to try and keep the motion from continuing.
The collapse of the first
Leave a comment