Definition - What does Expansion Joint mean?
An expansion joint is a device used to allow for the heat-induced expansion and reduction that takes place in various states of weather. They are designed to:
- Absorb heat-induced expansion and contraction of construction materials
- Absorb vibration
- Hold parts together
- Allow movement due to ground settlement or earthquakes
They are often used in the construction of bridges and sidewalks. They are also found between sections of buildings, railway tracks, piping systems, ships and other structures. They help to reduce cracking, leakage and failure.
An expansion joint is also known as a movement joint.
Corrosionpedia explains Expansion Joint
An expansion joint is used to allow the heat-induced expansion and reduction that takes place during different weather conditions. In building construction, an expansion joint is a mid-structure separation designed to relieve stress on building materials caused by building movement induced by:
- Thermal expansion and contraction caused by temperature changes
- Sway caused by wind
- Seismic events
Because building faces, concrete slabs and pipelines expand and contract due to warming and cooling from seasonal variation or due to other heat sources, they would crack under the stress if expansion joint gaps were not built into these structures.
Different types of expansion joints include:
- Fabric expansion joint
- Metal expansion joint
- Toroidal expansion joint
- Gimbal expansion joint
- Universal expansion joint
- In-line expansion joint
- Refractory lined expansion joint
Expansion joint failure can occur due to:
- Shipping and handling damage
- Improper installation
- Insufficient protection
- Improper anchoring, guiding and supporting
- Anchor failure in service
- System overpressure
- Excessive bellows deflection, torsion, bellows erosion
- Particulate matter in bellows convolutions