Compressive strength of high-strength bolts

High strength bolts are used to connect thick steel plates in the construction of steel structural engineering. High strength bolts are divided into torsional shear type high strength bolts and large hexagonal high strength bolts. The large hexagonal high-strength bolt belongs to the high toughness level of general foundation bolts, and the torsion shear type high-strength bolt is an improved version of the large hexagonal high-strength bolt, which has a stronger structure. It is necessary to first tighten the structure of the high-strength bolt, and then tighten it. The original tightening of high-strength bolts must use an impact type electric wrench or an adjustable torque electric wrench. However, there are strict regulations for the final tightening of high-strength bolts. Torque type electric wrenches must be used for the final tightening of high-strength bolts, and torque type electric wrenches must be used for the final tightening of high-strength bolts.

Why are high-strength bolts called high toughness? Is it due to its seismic rating? In fact, high-strength screws are often referred to as high-strength bolts because they are made of different raw materials. The raw materials for high-strength screws are made of high-strength steel plates or anchor bolts that must release greater preload. High strength screws are used to tighten the nut with a special wrench, which facilitates the creation of a controllable pre tightening force for the anchor bolt. According to the nut and base steel plate, create the same pre working pressure on the connected parts. High strength screws are crucial for connecting highway bridges, train tracks, high-pressure and high-pressure machinery and equipment. According to the specific characteristic level of foundation bolts above grade 8.8, they are called high-strength bolts. At present, the national industry standard only lists M39. For high-strength bolts with larger sizes and sizes exceeding 10-15% in length, Chinese production and manufacturing are still very short. In terms of compressive strength level, high-strength screws are widely used. The compressive strength levels for general applications are 8.8s and 10.9s, with the highest compressive strength level being 10.9. The compressive strength level of general anchor bolts is relatively low, generally 4.4, 4.8, 5.6, and 8.8.

From the perspective of crustal stress characteristics, high-strength bolts release prestressed reinforcement and transmit external force according to friction. The shear stress of general screw connections is transmitted based on the shear stress of the anchor bolt rod and the working pressure at the hole edge. The pre tightening force caused by tightening the nut is not significant, and its harm can be ignored. In addition to the plateau material compressive strength of high-strength bolts, a very large amount of prestressed reinforcement is also released on the anchor bolts, which creates the extrusion pressure between the connecting members, and then creates a very large sliding friction force upward in the direction of the vertical split screw. Moreover, the preload, ground anti slip index and various raw materials of steel all immediately endanger the bearing capacity of high-strength bolts. According to the characteristics of crustal stress, it can be divided into pressure bearing type and friction type. The minimum specification and model for high-strength bolts is M12, and generally M16-M30 is used. The characteristics of super large foundation bolts are unstable, so they should be carefully applied in the design scheme.