High strength bolt connection has the advantages of simple construction, good mechanical performance, removability, fatigue resistance, and no looseness under dynamic load. It is a promising connection method.

The high-strength bolt is tightened with a special wrench to make the bolt produce a huge and controlled pre tension. Through the nut and the base plate, the pre pressure of the same size is also generated on the connected parts. Under the pre pressure, a large friction force will be generated along the surface of the connected parts. Obviously, as long as the axial force is less than this friction force, the members will not slip and the connection will not be damaged. This is the principle of high-strength bolt connection.

High strength bolt connection depends on the friction between the contact surfaces of the connectors to prevent them from sliding. In order to make the contact surfaces have sufficient friction, it is necessary to increase the clamping force of the components and the friction coefficient of the contact surfaces of the components. The clamping force between members is achieved by applying pre tension to the bolts, so the bolts must be made of high-strength steel, which is why it is called high-strength bolt connection.

In high-strength bolted connections, the friction coefficient has a great influence on the bearing capacity. The test shows that the friction coefficient is mainly affected by the form of the contact surface and the material of the component. In order to increase the friction coefficient of the contact surface, sandblasting, wire brushing and other methods are often used to treat the contact surface of components within the connection range.