Expansion joints are used in buildings and other structures to absorb vibrations and temperature-induced movement. These joints also provide structural support to the building envelope. They are typically used in long-pipe systems and near boilers and heat exchangers. The joints are made of a flexible material, which is glued to an approach concrete. These are then sealed with hot rubber sealant. The seal protects the material from deterioration.
Several types of joints are available. They can be non-metallic or made of metal. These can be single ply or composite materials, which have multiple layers of heat-resistant flexible materials. The most common type is made of metal bellows. Compared to pipes, they offer more elasticity and a better ability to accommodate larger movements.
Modern day assemblies can handle high thermal expansion, wind gusts, and earthquakes. If the joint is not properly designed, it can create cracks in the facade and other elements of the structure. In order to prevent this, a designer needs to specify the angular and lateral movement to be accommodated by the joints.
In addition to expansion joints, there are other components that are needed for a successful construction project. These components include purge connectors to keep particulate media from accumulating in the joints. Additionally, a ceramic fiber barrier is sometimes used to prevent corrosion of particulate media. Lastly, the joint itself is warrantied for its continuity of sealing and the ability to maintain its integrity.
In order to install an expansion joint, the concrete must be prepared. The gap between the wall and the structure must be kept small, as the gap may expand seasonally. If this is not possible, water can be used to make the expansion joint watertight. This will ensure that the joint system remains intact as the gap shrinks.
Expansion joints are commonly installed between sections of a building, such as a pool deck and a coping. However, expansion joints they are also found between roadway and approach panels, turbines, and boilers. They can be made of various materials, including foam-like or non-metallic materials. In order to ensure the safety of the building occupants, expansion joints must be correctly located and filled.
When choosing an expansion joint, you should consider the total length of the structure. The length of the joint should be large enough to accommodate the anticipated axial and lateral deflections. When selecting the joint, you should also choose a material that will extend to the full width of the opening. A sealant may also be used to make the opening watertight.
To keep the interior of the expansion joint from moving and breaking, an internal liner is often recommended. This can help to minimize turbulence across the bellows. You may also want to choose a cover for the inner bellows. This can be either removable or permanent.
In order to ensure the integrity of the joint during fire, a hose-stream test is required. This test can be performed at the local MnDOT district office. This will demonstrate that the seal is still in place after a fire.