When the steel structure is damaged, we need to find and solve the problem immediately. The main factors of steel structure damage are:

1. The structure's bearing capacity is insufficient due to load changes, overdue service, and changes in codes and regulations;

2. Due to all kinds of accidental deformation, distortion, disability and sag of the component, the section of the component is weakened, the rod is warped and the connection is cracked;

3. Deformation, cracking and warping of components or joints caused by temperature difference;

4. The section of steel structure members is weakened due to corrosion of chemical substances and electrochemical corrosion;

5. Others include design, production, construction errors and illegal use and operation during the service period. 

There are three main technical measures for steel structure reinforcement:

1. Cross-section reinforcement method: steel is used to reinforce parts or the whole length of the component, and the whole part is made to bear common stress;

2. Change the calculation diagram: add additional support, adjust the load distribution, reduce the level of internal force, force displacement on the statically indeterminate structure support, reduce the peak stress;

3. Pestressed cable method: use high strength cable to strengthen the weak link of the structure or improve the overall bearing capacity, stiffness and stability of the structure.