A device used to permit a structure to expand or contract without breakage. In residential construction, a bituminous fiber strip is used to separate blocks, units or slabs of concrete to prevent cracking due to expansion as a result of temperature changes.
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An expansion joint or movement joint is an assembly designed to safely absorb the temperature-induced expansion and contraction of construction materials, to absorb vibration, to hold parts together, or to allow movement due to ground settlement or earthquakes. They are commonly found between sections of buildings, bridges, sidewalks, railway tracks, piping systems, ships, and other structures.
Building faces, concrete slabs, and pipelines expand and contract due to warming and cooling from seasonal variation, or due to other heat sources. Before expansion joint gaps were built into these structures, they would crack under the stress induced.