The main factors of steel structure damage are:
1) Insufficient structural bearing capacity due to load changes, overtime service, changes in specifications and procedures.
2) The deformation, distortion, disability, depression, etc. of the component due to various accidents cause the section of the member to be weakened, the member to warp, the connection to crack.
3）The deformation or cracking of the member or joint caused by the temperature difference.
4) Corrosion due to chemical attack and electrochemical corrosion cause the structural section of the steel structural member to be weakened.
5) Others include errors in design, production, construction, and illegal use and operation during the service period.