High-strength bolts apply pre-tension and transmit external force by friction

High-strength bolts are high-strength bolts and are a standard part. High-strength bolts are mainly used in steel structure engineering to connect the joints of steel structural steel plates. A very important feature of high-strength bolts is that the construction of single-use high-strength bolts must be tightened immediately after initial tightening. The first-time high-strength bolts need to use impact-type electric wrenches or torque-regulated electric wrenches; and the final high-strength bolts are strict. It is required that the torsion-shear type electric wrench must be used for the final tight-twist type high-strength bolt. The torque-type electric wrench must be used for the final tightening type high-strength bolt. The construction of the high-strength bolt must be tightened first and then tightened. Electric wrench or torque adjustable electric wrench; and the final tight high-strength bolt has strict requirements. The torsion-shear type electric wrench must be used for the final tight-twist type high-strength bolt, and the torque type electric wrench must be used for the final tightening type high-strength bolt.

High-strength bolts apply pre-tension and transmit external forces by friction. Ordinary bolt connection relies on the shearing of the bolt and the pressure of the hole wall to transmit the shear force. When the nut is tightened, the pre-tension is small, and the influence is negligible. However, the high-strength bolt not only has a high material strength, but also exerts a large bolt. The pre-tensioning force causes a pressing force between the connecting members, so that a large frictional force is perpendicular to the screw direction, and the pre-tensioning force, the anti-slip coefficient and the type of the steel directly affect the bearing capacity of the high-strength bolt. The friction type high-strength bolt has the sliding state between the slabs as the limit state of the bearing capacity; the pressure-type high-strength bolt has the sliding between the slabs as the normal use limit state, and the connection failure is the limit state of the bearing capacity.

High-strength bolts do not fully exploit the potential of the bolt. In practical applications, friction-type high-strength screws should be used for important structures or structures subjected to dynamic loads, especially when the load causes reverse stress. In this case, the unutilized bolt potential can be used as a safety reserve.

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