Fastener Connection Engineering Supervision Control Points
(1) The supervisor shall witness the anti-slip coefficient test of the friction surface of the high-strength bolted connection, and the anti-slip coefficient shall meet the design requirements. It should be noted that the sandblasting of the connected friction surface of the steel structure should meet the quality requirements of the test plate that has passed the anti-slip coefficient test of the connected friction surface. (The anti-slip coefficient of the friction surface of the high-strength bolted connection is related to the type of steel, the type of sand used for surface treatment, wind pressure, sand blasting time, and the degree of corrosion of the friction surface before the test. Therefore, the steel structure production unit must be representative of the anti-slip coefficient test. The treatment of the test plate should be consistent with the actual production, the specification requires that a set of tests should be carried out for every 2,000 tons of steel structure, and each set of tests should have six pairs of test plates, of which three pairs should be tested before the production of the steel structure, and the other three pairs should be re-tested before the installation of high-strength bolts of the steel structure, in order to verify that the anti-slip coefficient of the friction surface of the high-strength bolt connection is still within the specification or design requirements. In the production of steel structure, if the pretreatment site of friction surface of high-strength bolt connection is changed, or the treatment method is changed, the anti-slip coefficient test must be carried out again.
(2) The installation quality of the friction surface of the high-strength bolt connection and the twisting degree of the high-strength bolt shall be inspected by not less than 10% respectively. The torque wrench should be calibrated, and the torque wrench should be reviewed before and after each shift, and the inspection record should be made. Within 1h and 48h after the final screwing, the supervisor shall check the final screwing torque with the construction unit. At the same time, check that the bolt fastener should be 2-3 fasteners (10% of the bolt fastener is allowed to expose 1 fastener or 4 fasteners). (The construction unit should prepare two torque wrenches, one construction wrench, the error is within 5%, the other as a detection wrench, the error is within 3%. Test the construction wrench before and after each shift. High-strength bolts cannot be used as positioning bolts. The initial and final screwing of high-strength bolts should be completed within 24 hours. The final torque of the high-strength bolt is tested using the test wrench.)
(3) If the anti-slip coefficient test of the friction surface of the high-strength bolt connection is qualified, the quality certificate of the high-strength bolt is qualified and valid, the final torque inspection is qualified, and the supervisor is qualified, the connection of the fastener is qualified.
