An expansion joint or movement joint is an assembly designed to safely absorb the heat-induced expansion and contraction of various construction materials, to absorb vibration, to hold certain 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.
Bridge Expansion Joint
Throughout the year, building faces, concrete slabs, and pipelines will expand and contract due to the warming and cooling through seasonal variation, or due to other heat sources. Before expansion joint gaps were built into these structures, they would crack under the stress induced.
Bridge Expansion Joints, as shown in the photo, are designed to allow for continuous traffic between structures accommodating movement, shrinkage, temperature variations on reinforced and prestressed concrete, composite and steel structures. They stop the bridge from bending out of place in extreme conditions.
Bridge expansion joints also allow enough vertical movement to allow bearing replacement without the need to dismantle the bridge expansion joint. There are various types of Bridge Expansion Joints that can accommodate movement from between 30 to 500 mm these include small movement (<50mm) expansion joints (), medium movement (50~100mm) expansion joints and large movement (>100mm) expansion joints.
Alumina rail expansion joint
The alumina rail expansion joint is designed to applied on the no load transfer required joint. Connected with special elastomeric sealing element (U shape type) provides good features as below:
Light weight but rigid stiffness Easy installation. Almost free maintenance.
Long Duty life. The corrosion protection on the alumina rail is anode treatments which keep the alumina rail in a 50 years duty life at least. (Film thickness is thicker than 12μm).
Providing leak proofing and effective drain.
3 colors for alumina rail : black, silver, and gold.