Regarding the final tightening time of high-strength bolts
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Many steel structures are assembled on the ground before being lifted into place; for example, the roof truss beams of steel structure factories, or the steel structures of pipe corridors are assembled piece by piece on the ground first before being lifted. So, for joints connected with high-strength bolts, should these bolts be fully tightened before lifting?
This forum isn’t active at all; no one is replying, so I’ll reply myself.
Generally not; there is also a process of adjustment and tightening
Lifting it without tightening it – won’t that cause slippage during lifting and damage to the bolts? Furthermore, the specifications require that the initial tightening and final tightening be completed within one day.
Just tighten it normally, and after installation, tighten it again
Generally, during the assembly of the steel structure, the pre-tightening force is set to 60%; once installation is complete and no further adjustments are needed, all bolts are tightened to the required torque within one day. Adjustments will be made based on the actual situation after implementation; with thousands of bolts, it’s not practical to assign one or two people to tighten them all in a day.