Precautions in various processes of steel structure

1、 Production

The production of steel structures includes many steps such as setting out, marking, cutting, and calibration. The anti slip coefficient of the friction surface treated with high-strength bolts should meet the design requirements.

After passing the production quality inspection, rust removal and painting shall be carried out. Generally, 30~50mm should be left at the installation weld seam for the time being without painting.

2、 Welding and connection

Welders must pass the exam and obtain a certificate of qualification, and must perform welding within their exam qualification items and recognized scope. After welding, the welding seam and parts specified in the process must be stamped with the welder's steel seal.

The welding and welding materials should match the base metal. The first and second level welds with full penetration should be inspected for internal defects and dents using ultrasonic and wave testing. When ultrasonic and wave testing cannot make a judgment on defects and dents, radiographic testing should be used.

The steel, welding materials, welding methods, etc. used by the construction unit for the first time shall be evaluated for the welding and welding process.

3、 Transportation

When transporting steel components, vehicles should be selected based on the length and weight of the steel components. The support points, extended lengths at both ends, and binding methods of steel components on the vehicle should ensure that the components do not deform or damage the coating.

4、 Installation

The installation of steel structures should be carried out according to the construction organization design, and the installation procedure must ensure the stability of the structure and not cause permanent deformation. When installing columns, the positioning axis of each section of the column must be directly led up from the ground control axis. After the main components such as columns, beams, and roof trusses of the steel structure are installed in place, they must be immediately calibrated and fixed.

The friction surface of components processed by the factory must be rechecked for anti slip coefficient before installation, and can only be installed after passing the inspection.

5、 Fire prevention and rust removal

1) The fire resistance performance of steel structures is poor. When the temperature reaches 550 ℃, the yield strength of the steel decreases to approximately 0.7 of the yield strength at normal temperature, and the structure reaches its strength design value, which may cause damage.

When designing, it is necessary to comply with the relevant fire protection regulations to ensure that the building structure meets the requirements of the corresponding fire protection standards. Within the time required by fire protection standards, the temperature of the steel structure should not exceed the critical temperature to ensure the normal load-bearing capacity of the structure.

2) Exposed steel structures may be severely corroded by the atmosphere, especially polluted atmosphere, and generally rust. This requires anti-corrosion treatment of the surface of the components to ensure the normal use of the steel structure. The method of anti-corrosion treatment is determined based on the surface conditions and service life requirements of the components.

American standard H-shaped steel