Brief Introduction of High-strength Bolt Bearing Performance

When the high-strength bolt is installed, the nut is tightened to make the screw produce pre-tension to compress the contact surface of the member. The friction of the contact surface prevents the connecting plates from sliding between each other to achieve the purpose of transmitting external force.

According to the force transmission mechanism, high-strength bolts are divided into friction-type high-strength bolts and pressure-bearing high-strength bolts. The structure and installation of these two bolts are basically the same. However, friction-type high-strength bolts transmit load by friction, so the difference between the screw and the screw hole can reach 1.5-2.0mm. The force transmission characteristics of pressure-bearing high-strength bolts ensure that under normal use conditions, the shear force does not exceed the frictional force, which is the same as the friction-type high-strength bolts. When the load increases again, relative slippage will occur between the connecting plates. The connection depends on the shear resistance of the screw and the pressure of the hole wall to transmit force, which is the same as the ordinary bolt, so the difference between the screw and the screw hole is slightly smaller, 1.0~1.5mm. (Guide: Matters needing attention when constructing high-strength bolts)

Compared with pressure-bearing high-strength bolts, friction-type high-strength bolts have less deformation, lower bearing capacity, and good fatigue resistance and dynamic load resistance. The pressure-bearing high-strength bolt connection has high bearing capacity, but large shear deformation, so it is generally only used for connections in structures that bear static loads and indirectly bear dynamic loads.