The construction of steel structures is different from the construction of ordinary reinforced concrete, and the requirements for stability are higher. According to incomplete statistics, there are 9 steel structures out of 10 buildings in the past decade in which there have been structural safety incidents. It can be seen that the incidence of incidents in steel structure construction is very high. The root of the problem is that the steel structure construction has light weight, large span, weak wind resistance and lateral displacement resistance, and high requirements for stability, while the domestic construction technology is uneven, They often carry out blind construction and take risks to copy the construction experience of reinforced concrete into the steel structure, resulting in skew, excessive deformation and even collapse. Therefore, the construction of steel structure shall be strictly required, constructed according to the plan, and inspected by a professional testing company throughout the process

3. Check and judge the appearance damage of the steel members of the house, such as cracks, damage, coating peeling, steel corrosion, node damage, welding appearance defects, connection and fastening.

4. Magnetic particle testing or penetrant testing shall be selected according to national standards to determine the surface quality of steel members.

5. Some steel roof trusses and steel structural members shall be selected according to relevant national testing and inspection standards, and ultrasonic or magnetic particle testing shall be used for weld testing to determine whether there are defects such as pores, slag inclusions, crater cracks, arc scratches, etc.

6. Axial force meter and torque wrench are selected to detect and judge the torque coefficient of high-strength bolts at the joint of steel structure bolts.

7. The electronic theodolite is selected to measure the straightness of the vertical components of the house, and analyze whether the house presents tilt, deformation and uneven settlement. The specific inspection quantity is confirmed according to the actual situation on site and relevant standards.

8. The total station or pull wire method shall be used to detect and judge the deflection and deformation of roof truss, truss and its members.

9. Vernier caliper and micrometer shall be selected for section steel members to detect and judge the thickness of steel.

10. The ultrasonic thickness gauge shall be selected for the pipe steel members to inspect and judge the wall thickness of the pipe.

11. The surface hardness method is selected to test and judge the strength of steel.

12. The coating thickness gauge is selected to detect and judge the thickness of anti-corrosion or fireproof coating of steel members.

13. Magnetic particle flaw detection shall be carried out for the bolt ball of the grid structure according to the national standard.

14. According to the actual on-site testing data and planning requirements, according to the Load Standard for Building Structures (GB50009-2012) and the relevant national standards for building structure planning, the bearing capacity of the upper structure of the house is checked to assess whether the current bearing capacity of the house can meet the national standard requirements and the requirements for safe use in the future.