Washboarding
From Wikipedia, the free encyclopedia
Washboarding is the name in North America of the process which results in roads (particularly gravel roads or dirt roads) developing a series of regular bumps with short spacing in the road surface. The result is called a washboard road.
In Australia, Africa and Asia the equivalent terms are road corrugations or corrugated roads.
Washboarding is an instability that occurs when vehicles move above a critical speed, that depends on the properties of the vehicles and the road surface. If all the vehicles move below their critical speed the road will remain flat, but if they move faster, ripples will slowly grow and move in the direction of the vehicles. It has been argued that the vehicle's suspension is important, but this can not explain why washboard road forms when vehicles' suspensions vary so much. Many have argued that suspension is irrelevant and recent experiments confirm that washboard road forms without suspension [1] The contrasting points of view are in the references. A similar instability also occurs on train tracks, where it is known as roaring rails, and between rollers in machinery such as printing presses.
[edit] Prevention
Washboarding is battled by scraping the roads with bulldozers. However, the effect does not last long. The only way to prevent them from appearing is to drive very slowly - about 5 mph.[2]
[edit] External links
- ^ Washboard Road, by N. Taberlet, S. Morris and J. McElwaine
- ^ Road Bumps: Why dirt roads develop a washboard surface, Science News vol. 172, p. 116 (2007).
- Preventing Washboarding by Ken Skorseth, accessed June 2, 2006
- Ask an engineer: Washboarding, accessed June 2, 2006
- Q: Why are there ruts on dirt roads? at Google Answers, accessed June 2, 2006
