The Tacoma Narrows Bridge is a pair of twin suspension bridges in the U.S.which opened in July 1940 and collapsed four months later, as well as the replacement of the original bridge which opened in 1950 and still stands today.Its main span collapsed into the Tacoma Narrows four months later on November 7, 1940, at 11:00 AM (Pacific time) due to a physical phenomenon known as aeroelastic flutter caused by a 67 kilometres per hour (42 mph) wind.
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| Tacoma bridge[1940] |
The main cause of this disaster is Aeroelastic flutter, that is Dynamic Aeroelasticity studies the interactions among aerodynamic, elastic, and inertial forces.That is, the vibrational movement of the object increases an aerodynamic load, which in turn drives the object to move further. If the energy during the period of aerodynamic excitation is larger than the natural damping of the system, the level of vibration will increase, resulting in self-exciting oscillation. The vibration levels thus build up are only limited when the aerodynamic or mechanical damping of the object matches the energy input, which often results in large amplitudes and can lead to rapid failure.This effect is known as Aeroelastic flutter.
This bridge also got the name “Galloping Gertie” due to its unusual twisting and rolling behavior.At the time of collapsing the bridge
Video of collapsing:
The collapse of the bridge was recorded on film by Barney Elliott, owner of a local camera shop. The film shows Leonard Coatsworth leaving the bridge after exiting his car. In 1998, The Tacoma Narrows Bridge Collapse was selected for preservation in the United States National Film Registry by the Library of Congress as being culturally, historically, or aesthetically significant. This footage is still shown to engineering, architecture, and physics students as a cautionary tale Elliot's original films of the construction and collapse of the bridge were shot on 16 mm Kodachrome film, but most copies in circulation are in black and white because newsreels of the day copied the film onto 35 mm black-and-white stock.
The collapse of the bridge was recorded on film by Barney Elliott, owner of a local camera shop. The film shows Leonard Coatsworth leaving the bridge after exiting his car. In 1998, The Tacoma Narrows Bridge Collapse was selected for preservation in the United States National Film Registry by the Library of Congress as being culturally, historically, or aesthetically significant. This footage is still shown to engineering, architecture, and physics students as a cautionary tale Elliot's original films of the construction and collapse of the bridge were shot on 16 mm Kodachrome film, but most copies in circulation are in black and white because newsreels of the day copied the film onto 35 mm black-and-white stock.
