Hainan Steel Supermarket
Construction preparation
1. The production and installation of steel structures should meet the requirements of the construction drawing design. When it is necessary to modify the design, the consent of the original design unit should be obtained and a design change document should be signed.
2. Before the construction of steel structure engineering, the production and installation units should prepare the production process and installation construction organization design according to the requirements of the construction drawing design.
3. The production and installation of steel structures should be carried out in accordance with process requirements and construction organization design, and process inspections should be carried out. Only after the previous process is qualified can the next process be constructed.
4. The construction and acceptance of steel structure engineering should use measuring instruments that have passed metrological verification and should be operated in accordance with relevant regulations. The steel rulers and other testing instruments used for production, installation, and quality inspection should have corresponding accuracy and be verified as qualified.
5. The construction drawings and other technical documents are complete, and the construction drawings have been reviewed.
6. The technical personnel have provided technical briefing to the relevant construction personnel.
7. Complete materials and reasonable labor arrangement.
8. Before installation, the foundation has been handed over and accepted as qualified.
9. The prefabrication site should have a platform that meets the construction requirements, production equipment and facilities such as semi-automatic cutting machines, cranes, welding machines, sandblasting equipment, etc. The construction site should have smooth roads, a flat site, and electricity that meets the requirements. 10. Welders participating in welding must have a corresponding welder qualification certificate, and special occupations must hold a certificate to work.
Procurement and inspection of materials
1. Engineering and technical personnel should accurately understand the construction drawings and prepare detailed material plans based on the construction drawings.
2. When preparing the material plan, full consideration should be given to the on-site prefabrication situation, and the fixed length dimensions should be indicated.
3. order according to the materials and specifications required by the design, and do not substitute them arbitrarily. If substitution is required, the consent of the design unit should be obtained in advance.
4. When materials enter the factory, the steel, fittings, and welding materials used in the steel structure must have a product qualification certificate or a re inspection report, and should comply with the design requirements and relevant national standards.
5. In order to avoid mixing materials, a strict storage system should be implemented, and acceptance and stacking should be carried out according to the type, steel grade, and specification. Clear distinction should be made between pillars, main beams, support beams, reinforcement plates, and other components.
6. Material requisition and distribution should be handled by a dedicated person and recorded in detail. The on-site material keeper should periodically organize and verify the materials for easy management.
7. The steel, fittings, and welding materials used in steel structure engineering must have a product qualification certificate or retest report, and should meet the design requirements. When there is doubt about the quality of materials, sampling inspection should be carried out in accordance with the current relevant national standards.
8. The surface quality of steel should not only comply with the relevant national standards, but also meet the following requirements:(1) When there are defects such as rust, pitting, or scratches on the surface of the steel, its depth shall not exceed 1/2 of the negative deviation value of the thickness of the steel; (2) The rust level on the surface of steel should comply with the current national standard A, B, and C levels specified in the ' Rust level and rust removal level of steel surface before painting ' ; (3) The connecting materials and coating materials used in steel structure engineering should have a factory quality certificate and comply with the design requirements and relevant national standards.
Prefabrication of components
1. Before cutting materials, the construction team should carefully check the construction drawings, control the dimensions according to the diagram, and lay out in a 1:1 ratio. Only after measuring the accurate dimensions can the materials be cut and processed.
2. According to the drawings, components with the same structural type, specification, model, and size shall be uniformly cut, and their numbers shall be marked with paint in obvious areas. A semi-finished product list shall be provided for the cut materials, which is convenient for packaging and transportation.
3. The layout and marking should reserve welding shrinkage allowance and machining allowance such as cutting and planing during production and installation according to process requirements The layout and marking should reserve cutting, processing, and welding shrinkage allowances according to the process requirements. The allowable deviation of the material should comply with the following regulations:
Project allowable deviation
External dimensions of parts ± 1.0
Hole spacing ± 0.5
4. The layout platform should be flat, with a allowable deviation of ± 5 millimeters. The local unevenness error should be controlled within the range of 2-3mm. The surface of the steel plate should not have welding nodules or dirt. The support stiffness of the platform should ensure that the components do not lose stability or sink under their own weight pressure to ensure the levelness of the assembled components.
5. The allowable deviation of the layout and template (sample rod) should comply with the following regulations:
Project allowable deviation
Parallel line distance and segment size ± 0.5mm
Diagonal difference of 1.0mm
Width and length ± 0.5mm
Hole spacing ± 0.5mm
Angle of processing template ± 20 '
6. Gas cutting seam width=100%:2mm for sheet or profile thickness below 14mm, and 2.5mm for thickness between 16-26mm. For secondary material cutting, gas cutting should be used, and 1/2 plate thickness should be left at each cutting end, and not less than 5mm.
7. Before gas cutting, the rust, dirt, and other debris on the surface of the steel cutting area should be removed. After gas cutting, slag and splashes should be removed. The non verticality deviation between the steel cutting or shearing section and the surface should not exceed 10% of the plate thickness, and should not exceed 2 millimeters. Permissible deviation for gas cutting (mm)
Project allowable deviation
Part width=100% and length ± 3.0
Cutting surface flatness 0.05t and not greater than 2.0
Cutting depth 0.2
Local notch depth 1.0
Note:t represents the thickness of the cutting surface.
8. The thickness of the steel plate for mechanically cut parts should not exceed 12mm, and the cutting surface should be flat.
9. The deformation of steel before material marking and after mechanical cutting or cutting should be corrected to achieve the required straightness to prevent errors in measurement and combination. The thickness of the steel plate should not exceed 12.0mm, and the shear surface should be flat The deviation of deformed steel after correction should comply with the following table:allowable deviation for mechanical shearing (mm)
Project allowable deviation
Part width=100% and length ± 3.0
Edge missing edge 1.0
Perpendicularity of steel end face 2.0
10. The parts after marking should undergo strict self inspection and special inspection before cutting or after processing, so that the geometric dimensions of each part of the parts meet the specifications and requirements of the design drawing.
11. Correction and Forming (1) Carbon structural steel shall not undergo cold correction and cold bending when the ambient temperature is below -16 ℃, and low alloy structural steel when the ambient temperature is below -12 ℃. (2) The surface of the corrected steel should not have obvious dents or damage, and the scratch depth should not exceed 0.5mm. (3) Curved parts should be inspected using curved templates. When the chord length of the part is less than or equal to 1500mm, the chord length of the template should not be less than 2/3 of the part's chord length; When the chord length of the part is greater than 1500mm, the chord length of the sample should not be less than 1500mm, and the gap between the formed part and the sample should not exceed 2.0mm. (4) When hot working parts, attention should be paid to the heating temperature, and for low alloy structural steel, the cooling rate should not be too fast. When heating and correcting carbon structural steel and low alloy structural steel, the heating temperature should be selected based on the steel properties, but should not exceed 900 ℃. Low alloy structural steel should be slowly cooled after heating correction.
(5) The allowable deviation after steel correction should comply with the provisions of Table 6.11.5. The allowable deviation after steel correction is shown in Table 6.11.5.
12. Hole making and friction surface treatment (1) Mechanical method is used for hole making, and gas cutting into holes is strictly prohibited. (2) The edge of the bolt hole should not have cracks, burrs, or missing edges greater than 1mm. (3) The type of bolt hole (Class I hole or Class II hole) is determined by the design and meets the corresponding accuracy level. (4) The allowable deviation of bolt hole spacing should comply with the provisions of Table 6.15.4. The allowable deviation of bolt hole spacing
Table 6.15.4
Project allowable deviation
≤ 500 501-1200 1201-3000>3000
Any two holes in the same group with a spacing of ± 1.0 ± 1.5——
Distance between end holes of adjacent two groups ± 1.5 ± 2.0 ± 2.5 ± 3.0
(5) When the allowable deviation of bolt holes exceeds the above regulations, steel blocks shall not be used for filling. Welding rods that match the base material material can be used for repair welding and re drilling. (6) The grouping principle of bolt holes can be found in the provisions of Article 4.5.5 in GB50205. The provisions of Article 4.5.5 in GB50205-95 are as follows:(7) The grouping of bolt holes should comply with the following provisions:① All bolt holes connected to a connecting plate and a member in a node are grouped together; ② The bolt holes of the docking joint on one side of the splicing plate are a group; ③ The bolt holes between two adjacent nodes or joints are grouped together, but do not include the bolt holes specified in the above two clauses; ④ The continuous bolt holes on the flange of the bending component are a group of bolt holes per meter of length. (8) When using a grinding wheel to polish the friction surface, the polishing range should not be less than 4 times the bolt diameter, and the polishing direction should be perpendicular to the direction of the component's force. (9) The processed friction surface must not have burrs, welding scars, or dirt.