1. Expansion joint: Building components will expand and contract due to changes in temperature and humidity. For this reason, vertical joints are usually set in the appropriate parts of the building to disconnect the wall, floor, roof and other components of the building from the foundation and divide the building into several independent parts.
2. Settlement joints: different parts of the superstructure have great differences because of different stories or service loads; Or because the compressibility of foundation is very different, in short, when uneven settlement of foundation may occur, it is necessary to set joints to divide the structure into several parts to make the settlement of each part more uniform and avoid additional stress in the structure. This joint is called "settlement joint".
3. Anti-seismic joint: Its purpose is to divide a larger building into smaller parts to form a relatively independent anti-seismic unit, so as to avoid the damage caused by the uncoordinated vibration of the whole building caused by the earthquake.