Standards using high strength bolts

Use high-strength bolt pairs, the strength grade (after heat treatment process) is 10, and the bolts are 10.9 grade. The compression characteristics and calculation methods of general anchor cables and high-strength anchor rods are very different. The bearing capacity of high-strength bolts is firstly based on increasing the pre-tensioning force P in its internal structure, and then causing friction on the contact area between the connected parts, and then bearing external loads, while ordinary bolts immediately bear such loads. The high-strength bolt connection has the advantages of simple structure, good bearing capacity, detachability, fatigue relief, and not easy to loosen due to load effects, and is a promising interface method. High-strength bolts use a specially made wrench to tighten the nuts on the bolts to create a large and controllable pre-tension force, and add the same pre-stress tension specifications to the connected parts according to the nuts and pads. When subjected to prestressed tension, a large sliding friction is formed along the surface of the connected member. As long as the load is lower than the sliding friction, the member will not move and the connection will not crack. This is the basic principle of high-strength bolt connection. When high-strength bolts are connected, due to the friction between the contact surfaces of the connection, they cannot rotate against each other. In order to make the connection surface have sufficient friction, it is necessary to increase the clamping force of the connection and increase the friction coefficient of the connection. The clamping force between the components acts on the bolts through pre-tensioning, so the bolts must be made of high-strength steel, which is the so-called high-strength bolt connection. In high-strength bolted connections, the level of friction coefficient has a major impact on the bearing capacity. The test results show that the coefficient of friction depends critically on the morphology of the contact surface and the material of the component. In order to improve the friction coefficient of the contact surface, sandblasting and steel ball removal are often used in the construction process.To solve the contact surface of prefabricated components in the field of connection.