<input id="uauy4"></input> a. The winter construction of steel structure production and installation shall be carried out strictly in accordance with the relevant steel structure winter construction regulations.
b. When steel components are installed at positive temperature and at negative temperature, the shrinkage of components should be considered according to the difference in ambient temperature, and technical measures to adjust deviation should be taken during construction.
c. Welders who participate in the construction of negative temperature steel structures should undergo negative temperature welding process training, pass the examination, and obtain corresponding certificates.
d. The steel and related connecting materials used under negative temperature must be accompanied by a quality certificate, and the performance meets the requirements of the design and product standards.
e. The welding rod used under negative temperature shall not be exposed for more than 2 hours, and it shall be re-baked after more than 2 hours, and the number of baking of the welding rod shall not exceed 3 times.
f. Bake the flux according to the regulations before use, so that the water content does not exceed 0.1%.
g. High-strength bolts used under negative temperature must have a product certificate, and the torque coefficient and axial force must be re-inspected under negative temperature.
h. The paint used for steel structure under negative temperature shall not use water-based paint.
i. When the component is blanked, a shrinkage margin should be reserved, and the welding shrinkage and compression deformation should be coordinated with the shrinkage deformation of the steel under negative temperature.
j. When assembling the components, expand the assembly from the inside to the outside according to the order stipulated by the process, and do a test during the assembly of the negative temperature to determine the shrinkage value of the weld that needs to be reserved.
k. When assembling components, remove rust, burrs, soil, oil, ice and snow and other debris remaining in the joint 50mm, and keep the joints dry and free of residual moisture.
l. Multi-layer welding should be used when welding steel plates above 9mm under negative temperature. The welds should be welded layer by layer from bottom to top. Each weld is completed at a time. If the welding is interrupted, the welding defects should be removed before welding again. It is strictly forbidden to start the arc on the welding base metal.
m. When the steel structure is installed on site, in case of snow or wind speed above 6m/s, set up a protective shed.
n. The unqualified welds shall be removed and re-welded, and the welding shall be carried out in accordance with the provisions of the welding process of the steel structure under negative temperature.
o. When the ambient temperature is lower than 0°C, perform the painting process test before applying the anti-corrosion coating. When painting, the rust, oil stains, burrs, etc. on the surface of the component must be cleaned up, and the surface must be kept dry. No painting work is allowed in snowy weather or when there is thin ice on the components.
p. Take anti-skid measures when transporting and stacking steel structures in winter. The component stacking site is flat and solid without puddles, and the ground is free of icing. When the components of the same model are stacked, the components should be kept horizontal, and the shims should be placed on the same vertical line to prevent the components from slipping.
q. Before the steel structure is installed, its quality shall be re-inspected according to the requirements under negative temperature conditions, and the components that have been missed in the production and deformed during transportation and stacking shall be repaired and corrected on the ground.
r. When using steel cables to hoist steel components, anti-skid spacers should be added, the gusset plate that is hoisted at the same time as the components, and the fixtures required by the installer should be tied firmly with ropes.
s. According to the temperature conditions, the steel component installation sequence chart is compiled, and the installation shall be carried out in strict accordance with the specified sequence during construction.
t. Prepare the welding process for steel structure installation, and both ends of a component shall not be welded at the same time.
u. Before installation, remove ice, snow and dew on the surface of the components, but do not damage the coating.
v. Columns and main beams installed at negative temperature shall be corrected immediately, and the correct position shall be immediately fixed permanently. The components installed on the same day shall form a stable space system.
w. When installing high-strength bolt joints, there must be no snow or ice on the friction surface of the components, and no contact with dirt, oil and other stolen objects.
x.In addition to complying with the requirements of "Code for Construction and Acceptance of Steel Structure Engineering" (GB50250-95), the quality of steel structure installation under negative temperature should also be inspected and accepted according to design requirements.
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