Construction Connection Issues in Steel Structure Space Frames
What are the connection issues in steel structure space frame construction? SAFS Steel Structure Engineering Co., Ltd. will provide a brief introduction to some of them below:
(1) High-Strength Bolt Connection
1) Bolt contact surfaces do not meet the specifications, leading to difficulties in bolt installation, or the horizontal tightening of bolts does not meet the design specifications.
Root Causes:
① Surface residues such as rust and oil stains, as well as burrs and weld scars in bolt holes.
② Defects in the installation surface remain even after solving them.
Solutions:
① Rust, oil stains, and burrs in the bolt holes should be removed and cleaned one by one. Bolts intended for assembly must undergo rust prevention treatment before use and should not be used when announced for assembly. Manufacturers of steel structure space frames should have dedicated personnel responsible for storing and distributing bolts.
② Solve installation surface issues by considering the sequence of construction and try to resolve them before lifting whenever possible.
2) Damage to bolt threads; tightening the nut without care can jeopardize bolt installation.
Root Cause: Serious rust on the threads.
Solutions:
① Bolts should be selected, cleaned, and rust-proofed before use.
② Bolts with damaged threads should not be used temporarily, and forcing them into bolt holes is prohibited.
③ Pre-selected bolt components should be stored as sets, and they should not be interchanged during use.
(2) On-Site Welding Conditions:
- Quality cannot be ensured.
- Design specifications require full penetration welds for primary and secondary welds, but ultrasonic testing equipment was not used.
- Floor beams are not welded to columns.
- Arc stud welding was not used.
Solutions:
- Before welding the steel frame structure, verify the certification of the welding wire.
- Use welding rods as specified in the design and follow the manufacturer’s instructions and safety operating procedures.
- Welded seams should be free of cracks, weld scars, gas pores, weld lumps, and arc pits.
- Primary and secondary welds should not have defects such as misalignment or incomplete penetration.
- Primary and secondary welds should undergo non-destructive testing as required, and the anti-counterfeiting marks of welders should be checked on the required welds and locations.
- Weld seams that do not pass inspection should not be handled independently. After determining the modifications to the manufacturing process, they should be addressed. The repair frequency for weld seams in the same location should not exceed two times.