Dapeng Town Industrial Park, Tongshan District, Xuzhou City, Jiangsu Province, China
The steel space frame structure, also known as the spherical space frame or bolt-ball space frame, is formed by linking spatial framework members with balls, creating a spherical structure suitable for large-span spaces like sports arenas, industrial plants, and large coal sheds. For the safety control of space frame structures, SAFS Steel Structure Engineering Co., Ltd. provides the following key points:
1. Supports, brackets, and their connecting components use Q235B steel.
2. Steel balls: Bolt balls use Grade 45 steel as per the technical conditions of “Technical Specifications for High-Quality Carbon Structural Steel” GB699.
3. High-strength bolts: Should meet the Grade 10.9 specifications in GB1228-91 for “High-Strength Bolts for Steel Structures” and the provisions of GB/T16939 for “High-Strength Bolts for Bolt-Ball Joints of Steel Space Frames.” The material selected is 40Cr from GB3077. Finished products must not have quenching cracks at any depth or length, with a surface hardness of HRC32-36. Threads should conform to the tolerance standards in “General Purpose Screw Threads and Matching” GB197. The surface requires blackening treatment and anti-rust oil coating.
4. Threadless nuts: Use Q235B steel forgings; when the high-strength aperture is >30, use Grade 45 steel forgings.
5. Cone heads: Use Q235B steel forgings.
6. Steel pipes: Select Q235B steel from GB700, meeting the requirements of the current national standard “Carbon Structural Steel” GB700-88. It should have qualified guarantees for tensile strength, elongation, yield strength (or yield point), sulfur, phosphorus, carbon content, and cold bending tests. Spatial framework steel pipes should strictly follow processes such as rod cutting, welding, painting, inspection, etc.
Construction considerations:
1. Conduct tensile strength tests on the threads of large bolt holes in bolt-ball joints for finished spheres.
2. Implement quality control during the assembly process.
3. Prioritize construction and installation plans for space frame assembly, ensuring practical implementation.
4. Material must meet design requirements.
5. Emphasize controlling the deflection of the space frame under its own weight and loads, with the average deflection not exceeding 1.15 times the design value at measurement points.
6. The design of the spherical space frame must comply with relevant standards.
7. Perform unidirectional axial tensile and compressive load tests on ball joints, meeting stringent requirements for the base material.
8. Ensure that the reference axis and column top elevations comply with design and standards.
