High-strength bolt connection is to clamp the connecting plate parts through the large tightening pretension in the bolt rod
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Update time : 2021-01-05 13:29:08
The high-strength bolt connection is to clamp the connecting plate parts through the large tightening pretension in the bolt rod, which is enough to get a large friction force, thereby improving the whole bolt and the bolt stiffness of the connection. When the force is applied, according the different force requirements, it can be divided into two types: high-strength bolt friction type connection and high-strength bolt pressure-bearing type connection. The difference between the two types is that the limit state is different. Although they are the same type of bolts, but there much difference as following: 1.the high-strength bolt calculation method, 2.requirements, 3.scope of application. In the shear force resistance design, the high-strength bolt friction type connection is the limit state when the external shear force reaches the possible friction force provided by the bolt tightening force between the contact surfaces of the plate, which is to ensure that the internal and external shear force of the connection does not exceed friction force. The plates will not be relative sliding and deformation (the original gap between the thread rod and the wall of the hole is always maintained), and the connected plates, the whole bolt will take all the force. In the shear resistance design, for the high-strength bolt pressure-bearing connection, the external shear force is allowed to exceed the friction force. At this time, relative sliding deformation occurs between the connecting plates until the bolt rod contacts the hole wall, and then the connection depends on the bolt thread rod, the shear force and the pressure of the hole wall and the friction force between the contact surfaces of the plate, all together transmit the force. And the bolt thread rod shear force or the pressure of the hole wall is the limit state of the connection. Over all, friction-type high-strength bolts and pressure-bearing high-strength bolts are actually the same kind of bolts, it is just whether slippage is considered in the design. Friction-type high-strength bolts cannot slide and the bolts do not bear shearing force more than friction force. Once slipped, the design is considered to have reached a failure state, which is technically mature; pressure-bearing high-strength bolts can slide, and the bolts also bear shearing force.
