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Steel structure construction measures in rainy season and winter
Steel structure construction measures in rainy season
During the construction of steel structure buildings in rainy days, temporary protective shed should be set up, and the rain should not fall on the hot welding seam. If the welding part is wet, it must be wiped with dry cloth and dried with oxyacetylene flame before welding, so as to keep the joints dry without residual moisture.
When hoisting the steel structure, if there is water on the steel member, it shall be cleaned before installation, but the coating shall not be damaged. When installing the high-strength bolt joint, the friction surface of the member shall be clean, without water drop, rain, soil, oil and other dirt.
3. In rainy days, the steel structure components cannot be painted.
The construction of steel roof insulation can not be carried out in rainy days and strong wind above level 5.
5. In rainy days, because the air is humid, the welding rod should be stored moisture-proof and baked. The same welding rod should not be baked more than twice, and the management personnel should make baking records in time.
In case of gale weather, steel column, steel main beam, steel support and other large section steel components shall be corrected immediately, and fixed permanently after correct position correction to prevent unilateral instability. Components installed on the same day shall form a space stable system.
Winter construction measures of steel structure
The winter construction of steel structure fabrication and installation shall be carried out in strict accordance with relevant winter construction regulations of steel structure.
When the steel members are manufactured at positive temperature and installed at negative temperature, the shrinkage of the members should be considered according to the difference of the ambient temperature, and the technical measures of adjusting the deviation should be taken in the 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.
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 welding rod used under negative temperature shall not be exposed for more than 2 hours, and shall be re baked for more than 2 hours, and the number of times of baking shall not exceed 3.
Before use, the flux should be baked according to the regulations, so that the moisture content is not more than 0.1%.
The high strength bolts used under negative temperature must have product certificate, and the torque coefficient and axial force shall be rechecked under negative temperature.
Under negative temperature, water-based coating shall not be used for steel structure workshop, warehouse, office, apartment and high-rise building.
When cutting steel members, shrinkage allowance shall be reserved, and welding shrinkage and compression deformation shall be coordinated with shrinkage deformation of steel under negative temperature.
During the assembly of steel members, the assembly shall be extended from the inside to the outside according to the sequence specified by the process. During the assembly at negative temperature, the test shall be carried out to determine the shrinkage value of the weld to be reserved.
When assembling steel members, remove the rust, burr, soil, oil, ice, snow and other debris left in the joint 50 mm, and keep the joint dry without residual water.
Multi layer welding shall be adopted when welding steel plate over 9mm under negative temperature. The welding seam shall be overlaid layer by layer from bottom to top. Each welding seam shall be completed at one time. If the welding is interrupted, the welding defects shall be removed before welding again. It is forbidden to strike arc on welding base metal.
When the steel structure is installed on site, if it is snowy or the wind speed is more than 6m / s, the protective shed shall be set up.
The unqualified steel structure welds shall be removed and re welded according to the regulations of steel structure welding process under negative temperature.
Steel structure building project of warehouse and workshop in Kazakhstan, Kirghiz Tanzania, Tajikistan, Turkmenistan, Uzbekistan ,When the ambient temperature of steel structure installation is lower than 0 ℃, the painting process test shall be carried out before painting the steel structure warehouse, steel structure workshop, steel structure building and anti-corrosion coating. When painting, the rust, oil stain, burr and other objects on the surface of components must be cleaned, and the surface shall be kept dry. Painting is not allowed in snowy days or when there is thin ice on the components.
When transporting and stacking steel structures in winter, anti-skid measures shall be taken. The stacking site of components shall be flat and solid, without puddles 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.
Before the installation of the steel structure, the quality of the steel structure shall be re inspected according to the requirements under the negative temperature condition, and the components that are not inspected during the production and deformed during the transportation and stacking shall be repaired and corrected on the ground.
When lifting the joint with steel rope, steel spacer shall be used.
The installation sequence chart of steel members shall be prepared according to the air 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. Both ends of a component shall not be welded at the same time.
The ice, snow and dew on the surface of components shall be removed before installation, but the coating shall not be damaged.
The columns and main beams installed under negative temperature shall be corrected immediately, the correct position shall be corrected and fixed permanently immediately, and the components installed on the same day shall form a stable space system.
During the installation of high-strength bolt joint, there shall be no snow and ice on the friction surface of the component, and no dirt, oil and other stolen goods.
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 50250-2020), but also be inspected and accepted according to the design requirements.