Sichuan steel structure - high-strength bolted connection inspection method

The connection methods of Sichuan steel structure are mainly divided into bolted connection, weld welding, rivet riveting, of which bolt connection is divided into ordinary bolt connection and high-strength bolt connection. Today we focus on the knowledge of bolted connection in steel structure engineering, how do we distinguish what kind of bolt connection method is used in which case during the construction of steel structure in Chengdu? Simply put, it is generally connected with high-strength bolts on the main steel structure as much as possible, even in the secondary steel, the load-bearing part needs to be connected with high-strength bolts. The final screw torque check should be carried out within 48 hours after the final screwing of the high-strength bolt connection pair is completed. The inspection methods of high-strength bolted connections are mainly divided into the following two:

Torque method test method: mark the relative position of the end of the nut and the nut, return the nut to about 60°, and use a torque wrench to determine the torque value when screwed back to the original position. The deviation between the torque value and the construction torque value is 10%, which is qualified.

Corner method test method:

1) Check whether the angle between the start line and the

end line drawn between the nut and the relative position after the initial screwing reaches the specified value.

2) Draw a line at the opposite position of the end of the nut and the nut, then loosen the nut completely, re-tighten the bolt according to the specified initial tightening torque and final tightening angle, and observe whether it coincides with the original drawing line. The final twisting angle deviation is qualified within 10.

Twist-shear type high-strength bolt construction torque inspection method: observe the unscrewing of the tail plum head. If the tail plum head is unscrewed, it is deemed that its final screwing torque meets the qualified quality standard, and the tail plum head is not unscrewed, and it should be inspected according to the above torque method or angle method. After the twist-shear high-strength bolt connection is finally screwed, except for those who cannot use a special wrench to finally unscrew the plum head due to structural reasons, the number of bolts that have not been unscrewed in the final screw should not be greater than 5% of the number of bolts of the node. All torsion-shear high-strength bolt connection pairs that have not been unscrewed by the torque head should be finally screwed out by the torque method or corner head, and the twist-shear high-strength bolt connection pair should be finally screwed and marked by the torque method or the angle method, and the tightening torque inspection should be carried out according to the provisions of the specification.

The above is the inspection method of high-strength bolted connection commonly used in Sichuan steel structure engineering, and we should strictly follow such methods and steps in the daily construction process to ensure the stability of the bolted connection.