Bai torsion shear type high strength bolt connection pair for steel structure is mainly used in industrial and civil buildings, highway and railway bridges. For tower, pipe support, hoisting machinery and other occasions where friction type connection of high strength bolt is required. It is characterized by an extra dodecagonal body at the end of the bolt.

安装时，须用特制的电扳手，其上下有两个套筒头，一个套在螺母的六角体上，另一个套在螺栓的十二角体上。拧紧时，对螺母施加顺时针力矩，对螺栓十二角体施加大小相等的逆时针力矩，使螺栓的末端与十二角体之间连接颈部承受扭剪，颈部剪断为止，则安装完成。这种扭剪型高强度螺栓为一次型使用的紧固件，安装后一般不予拆卸。

During installation, a special electric wrench must be used. There are two socket heads on the top and bottom, one on the hexagon of the nut and the other on the dodecagonal body of the bolt. When tightening, apply clockwise torque to the nut and counter clockwise torque of equal size to the dodecagonal body of the bolt, so that the connection neck between the end of the bolt and the dodecagonal body is subject to torsional shear, and the installation is completed until the neck is cut off. This kind of torsion shear high strength bolt is a kind of one-time fastener, which is not disassembled after installation.