|MLA Citation:||Bloomfield, Louis A. "Question 1160"|
How Everything Works 22 Jan 2018. 22 Jan 2018 <http://howeverythingworks.org/print1.php?QNum=1160>.
Most of the time, these waves aren't important and can be ignored. But occasionally some special event will cause enormous waves to begin traveling through a bridge. The classic example was the Tacoma Narrows Bridge in Washington State that collapsed in 1940 when wind-driven waves in its surface ripped it apart. The entire collapse was captured on film and is a fascinating to watch. When a large group of soldiers crosses a footbridge, they are often instructed to break step so that their rhythmic cadence doesn't excite intense waves that might damage the bridge. In general, modern bridges are engineered to dampen these waves—wasting their energy through friction or friction-like effects so that they die away quickly. While it might be fun to watch waves traveling along the surface of a bridge from a safe vantage point, you probably wouldn't want to be on a bridge when it was experiencing strong ones.