（1） Construction measures in rainy season

During the construction in rainy days, temporary protective shed should be set up, and the rainwater should not fall on the hot welding seam. If the welding part is wet, it must be cleaned with dry cloth and dried with oxyacetylene flame before welding to keep the joint dry and free of residual moisture.

2. During hoisting, if there is water on the component, it should be cleaned before installation, but the coating should not be damaged. When installing the high-strength bolt joint, the friction surface of the component should be clean, and there should be no water droplets, rain and contact with soil, oil and other dirt. 

3. Components can not be painted in rainy days.

4. The construction of roof insulation can not be carried out in rainy days and strong wind above level 5.

5. In rainy days, due to the humidity in the air, the welding rod should be stored in moisture-proof and baked. The same welding rod should not be repeatedly baked for more than two times, and the management personnel should make baking records in time. 

In case of windy weather, the column, main beam, support and other large components should be corrected immediately. After the correct position is corrected, permanent fixation should be carried out immediately to prevent unilateral instability. The components installed on the same day should form a spatial stability system. 

（2） . winter construction measures

The fabrication and installation of steel structure in winter shall be carried out in strict accordance with relevant regulations on winter construction of steel structure.

2. When steel members are manufactured at positive temperature and installed at negative temperature, the shrinkage of steel members shall be considered according to the difference of ambient temperature, and technical measures for adjusting deviation shall be taken during construction.

3. Welders participating in the construction of negative temperature steel structure shall pass the negative temperature welding process training, pass the examination and obtain the corresponding certificate.

4. The steel and relevant connecting materials used under negative temperature shall be attached with quality certificate, and the performance shall meet the requirements of design and product standards.

5. The exposed electrode under negative temperature shall not be exposed for more than 2 hours, and shall be baked again after 2 hours, and the baking times shall not exceed 3 times.

6. The flux shall be baked according to the regulations before use, so as to make its moisture content not exceed 0.1%.

The high strength bolts used under negative temperature shall have product certificate, and the torque coefficient and axial force shall be rechecked under negative temperature.

8. Water based coating shall not be used for steel structure under negative temperature.

9. Shrinkage allowance shall be reserved during component blanking, and welding shrinkage and compression deformation shall be coordinated with shrinkage deformation of steel under negative temperature.

During the assembly of components, the assembly shall be expanded from the inside to the outside according to the sequence specified in the process, and the weld shrinkage value to be reserved shall be determined through the test during the assembly at negative temperature.

When assembling components, remove rust, burr, soil, oil, snow and other debris left in the joint for 50 mm, and keep the joint dry without residual moisture.

When welding steel plates above 9mm under negative temperature, multi-layer welding shall be adopted. The welding seams shall be overlaid layer by layer from bottom to top. Each weld shall be welded at one time. If the welding is interrupted, the welding defects shall be removed before welding again.It is forbidden to strike arc on the welding base metal.

When installing steel structure on site, in case of snow or wind speed above 6m / s, set up protective shed.

The unqualified weld shall be removed and re welded, and the welding shall be carried out according to the regulations of steel structure welding process under negative temperature.

When the ambient temperature is lower than 0 ℃, the coating process test shall be carried out before the application of anti-corrosion coating. Rust, oil stain, burr and other matters on the surface of the component must be cleaned and the surface shall be dry.Painting shall not be carried out in snowy days or when there is thin ice on the components.

During transportation and stacking of steel structures in winter, anti-skid measures shall be taken, and the stacking site of components shall be flat and solid without water pit and ice on the ground.When the components of the same type are stacked, the components shall be kept horizontal, and the pad iron shall be placed on the same vertical line to prevent the components from slipping.

The quality of steel structure shall be rechecked according to the requirements under negative temperature condition before installation. The components that are not inspected during manufacturing and deformed during transportation and stacking shall be repaired and corrected on the ground.

When using steel cable to lift steel members, anti-skid spacer should be added. The joint plate lifted with the component at the same time, and the clamps and other objects needed by the installation personnel should be bound firmly with ropes.

The installation sequence chart of steel members shall be prepared according to the temperature conditions, and the installation shall be carried out in strict accordance with the specified sequence during construction.

The installation and welding process of steel structure shall be prepared, and both ends of one component shall not be welded at the same time.

Before installation, remove ice, snow and dew on the surface of components, but do not damage the coating.

The column and main beam installed at negative temperature shall be corrected immediately, and the correct position shall be corrected immediately. The components installed on the same day shall form a stable space system.

During installation of high-strength bolt joint, there shall be no snow and ice on the friction surface of the components, and no contact with dirt, oil, etc.

The installation quality of steel structure under negative temperature shall not only comply with the requirements of code for construction and acceptance of steel structure engineering (GB 50250-95), but also be inspected and accepted according to the design requirements.