High strength bolt connection has developed into one of the main connection forms of steel structure with welding simultaneously. It has the advantages of good mechanical performance, fatigue resistance, seismic performance, high connection stiffness, simple construction, etc., and is widely used in the field connection of building steel structure and bridge steel structure.
High strength bolt connection can be divided into friction type connection, friction bearing type connection, pressure bearing type connection and tension type connection according to its stress condition, among which friction type connection is the basic connection form widely used at present.
(1) High strength hexagon head bolt
High strength large hexagon head bolts for steel structure are divided into 8.8 and 10.9 grades. One connection pair is one bolt, one nut and two washers. High strength bolt connection pairs shall be manufactured in the same batch to ensure the stability of torque coefficient. The average value of torque coefficient of connection pairs in the same batch is 0.110-0.150, and the standard deviation of torque coefficient shall not be greater than 0.010.
(2) Torsional shear type high strength bolt
One bolt connection pair of torsional shear type high strength bolt for steel structure is one bolt, one nut and one washer, which is suitable for steel structure of friction type connection.