The high-strength bolt connection is to clamp the plates of the connection plate through a large tightening preload in the bolt rod, which is sufficient to generate a large friction force, thereby improving the integrity and rigidity of the connection. The difference in force requirements can be divided into two types: high-strength bolt friction type connection and high-strength bolt pressure type connection. The essential difference between the two is the limit state. Although they are the same type of bolt, they are in terms of calculation methods, requirements, and scope of application. They are all very different. In the shear design, the high-strength friction-type connection is the maximum possible friction provided by the bolt tightening force between the contact surfaces of the plates when the external shear force reaches the limit, which means that the internal and external shear force of the connection does not exceed the entire period of use. Maximum friction. The plate does not undergo relative sliding deformation (the original gap is always maintained between the screw and the hole wall), and the connected plate is subject to overall elastic force. In the shear design, the external shear force is allowed to exceed the maximum friction force in the high-strength bolt pressure-type connection. At this time, relative sliding deformation occurs between the connected plates until the bolt rod contacts the hole wall. After that, the connection depends on the bolt rod. The body shear and the hole wall pressure and the friction between the contact surfaces of the plates transmit the force. Finally, the shearing of the shaft or the hole wall pressure failure is used as the limit state of the connection shear. In short, friction high-strength bolts and pressure-type high-strength bolts are actually the same bolt, but whether the design considers slippage. Friction-type high-strength bolts must not slide, and the bolts do not withstand shear forces. once slipped, the design is considered to be in a damaged state, which is technically mature; pressure-bearing high-strength bolts can slide, and the bolts also undergo shear forces. The ultimate damage is equivalent to ordinary Destruction of bolts (sheared bolts or crushed steel plates).