http://www.ck12.org Chapter 11. Vibrations and Sound
FIGURE 11.10
A classic example of an unfortunate consequence of a forced vibration at resonant frequency is what happened to
the Tacoma Narrows Bridge, in 1940. See the link below.
http://www.youtube.com/watch?v=3mclp9QmCGs
InFigure11.11, the bridge is beginning to resonate, in part, due to the frequency of vibration of the wind gusts. In
Figure11.12, we see that the bridge is no longer able to respond elastically to the tremendous amplitude of vibration
from the forced vibration of wind energy (at its resonant frequency), and it is torn apart.
FIGURE 11.11
Modern bridges are built to avoid this effect, but through history there are a number of documented situations where
a forced vibration at resonance had dire results. The Broughton Suspension Bridge (1831) and the Angers Bridge
(1850) are two examples of bridges believed to have collapsed due to the effect of soldiers marching at a regular
pace that caused resonance. The Albert Bridge in West London, England has been nicknamed The Trembling Lady
because it has been set into resonance so often by marching soldiers. Though soldiers no longer march across the