An Expansion Joint or movement joint is an assembly designed to safely absorb the heat-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.
In building construction, an expansion joint is a mid-structure separation designed to relieve stress on building materials caused by building movement induced by:
Because the joint bisects the entire structure, it marks a gap through all building assemblies--walls, floors, roofs, decks, planters, plazas, etc. This gap must be filled to restore the waterproofing, fire proofing, sound proofing, air barrier, roof membrane, trafficable surface and other functions of the building elements it bisects.
Expansion joint systems are used to bridge the gap and restore building assembly functions while accommodating expe