Expansion Joint

Expansion Joint

Expansion Joint
Image credit: Yarnell-Waring Company
A Double End Flanged Expansion Joint of Sleeve Type which is used in Piping Systems to allow for expansion and contraction.

A joint that is designed specifically for the prevention of destructive stresses developing in a rigid structure upon thermal expansion.

This piece of machinery is placed between two parts to permit expansion and contraction of the parts. Such expansion and contraction are typically the result of temperature change but may also be the result of mechanical pressure. They are commonly used in piping systems. The sleeve type is composed of a metal sleeve in which one or the other pipes being joined are free to slide as they contract and expand. Packing material is used to tighten the joint. Corrugated expansion pipe joints operate through a principal of flexing, the corrugation material closing expands and closes as the pipes expand and contract, similar to an accordion. Flexible rubber joints are sometimes also used.

In construction projects, such as roof trusses and long steel bridge spans and similar structures expansion joints are often necessary to permit the structure to expand in hot weather without defomation. These may consist of open spaces left between one end of the struction and adjoining parts. That end carries the load and is supported upon rollers, allowing movement as the structure undergoes contraction and expansion.

Expansion joints utilized in construction of concrete roadways, airport runways and other flat surfaces allow concrete room for expansion without buckling and contraction without forming cracks in it. This is accomplished by leaving open spaces between one end of the structure and adjoining segments. These spaces are sometimes filled with fibrous material containing asphalt.


  • The American Peoples Encyclopedia ©1960
  • Encyclopedia Britannica Micropedia ©1984
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