Steel structure. Bolts are divided into torsional shear high-strength bolts and large hexagonal high-strength bolts. Large hexagonal high-strength bolts belong to the high-strength grade of ordinary screws, while torsional shear high-strength bolts are an improved version of large hexagonal high-strength bolts. For better engineering construction, bolts are connecting parts of steel frame structures. According to their bearing capacity, they can be divided into general bolts and high-strength. 1. Spring washers should be placed according to the design points for dynamic load or bolted connection of key parts, and the spring washers must be set on the side of the nut. 2. The installation of high-strength bolts should be able to penetrate freely into the hole, and forced penetration is prohibited. High strength. The diameter of the bolted steel plate is slightly larger than the diameter of the bolt hole, and it must be formed by drilling. 3. High-strength. Bolt connection methods are generally divided into friction connection, tension connection and pressure connection. Among them, friction connection is the basic connection method commonly used at present. 4. High-strength. Bolt installation sequence: It needs to be developed from the part with higher bending stiffness to the free end that is not restrained. For the high-strength bolts in a joint, the initial tightening, re-tightening, and final tightening need to be tightened one by one from the center of the bolt group to the surroundings gradually. Each tightening is marked with different colors of paint to avoid missing tightening. The initial screwing, re-tightening and final screwing of the high-strength bolts in the same joint should be carried out within 24 hours. If there is no design requirement, it should be arranged according to the construction technology sequence of tightening high-strength bolts first and then electric welding (that is, first bolts and then welding).