High-strength bolts can bear larger loads than ordinary […]
High-strength bolts can bear larger loads than ordinary bolts of the same specification.
From the perspective of raw materials: high-strength bolts are made of high-strength materials. The screws, nuts and washers of high-strength bolts are made of high-strength steel. From the strength level: high-strength bolts are increasingly used. Two intensity levels of 8.8s and 10.9s are commonly used, of which the 10.9 level is mostly. The strength level of ordinary bolts is lower, generally 4.4, 4.8, 5.6 and 8.8. From the point of view of the force characteristics: high-strength bolts apply pre-tension and friction to transmit external forces. The ordinary bolt connection transfers the shear force by the shear resistance of the bolt and the pressure of the hole wall. The pretension force generated when tightening the nut is very small, and its effect is negligible. In addition to its high material strength, the high-strength bolt also exerts a large amount on the bolt. The pre-tension force causes a squeezing force between the connecting members, so that there is a large friction force perpendicular to the direction of the screw, and the pre-tension force, anti-slip coefficient and steel type directly affect the bearing capacity of high-strength bolts. From the use point of view: the bolt connection of the main components of the building structure is generally high-strength bolt connection. Ordinary bolts can be reused, high-strength bolts cannot be reused. High-strength bolts are generally used for permanent connections.