Difference between common bolt and steel structure bolt

       Difference between ordinary bolt and steel structure bolt:

       Common bolts:

       (1) recheck report of ordinary bolt with small tensile load

       (2) quality certification documents, Chinese marks and inspection reports of raw materials

       (3) material mobilization application for inspection and Supervision approval form

       Steel structure bolt:

       1. Inspection batch:

       2. Sampling quantity: spot check 8 bolts of each specification

       3. Inspection torque coefficient of steel structure bolt, inspection pre tension re inspection of torsional shear type high strength bolt

       4. Re inspection report of raw materials

       (1) inspection torque coefficient of steel structure bolts: there are more than 3000 sets of bolts in one batch, and 8 sets of bolts are randomly sampled for re inspection. The average torque coefficient of each group of 8 sets of connection pairs shall be 0.110-0.115, and the standard deviation shall be ≤ 0.010

       (2) pre tension re inspection for bolts of torsional shear steel structure: there are more than 3000 sets of bolts in one batch, and 8 sets of bolts to be installed in each batch are randomly sampled from the construction site for re inspection of torque coefficient.

       (3) quality certification documents of raw materials, Chinese marks and inspection reports (the inspection reports of torque coefficient and tightening axial force (pretension) shall be attached to the box respectively when the steel structure bolt connection pair and torsional shear steel structure bolt connection pair leave the factory)

       (4) material mobilization application and Supervision approval form

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