1. Fastening of high strength bolt: it must be carried out twice, and the first time is the initial tightening. The initial tightening should be 60% - 80% of the standard axial force (i.e. the designed pre tension), and the torque value of the initial tightening should not be less than 30% of the final tightening torque value. The second tightening is the final tightening. When the final tightening, the plum blossom chuck should be screwed off. In order to make all bolts in the bolt group bear uniform force, the initial tightening and final tightening should be carried out in a certain order.

2.一般接头：应从螺栓群中间顺序向外侧进行紧固。

2. General joints: the bolts shall be tightened from the middle to the outside.

3.从接头刚度大的地方向不受约束的自由端进行。

3. From the joint with high stiffness to the free end.

4.从螺栓群向四周扩散的方式进行。

4. Spread from the bolt group center to the surrounding.

初拧扳手应是可以控制扭矩的，初拧完毕的螺栓，应做好标记以供确认。为防止漏拧，当天安装的高强螺栓，当天应终拧完毕。终拧应采用专用的电动扳手，如个别作业有困难的地方，也可以采用手动扭矩扳手进行，终拧扭矩须按设计要求进行。用电动扳手时，螺栓尾部卡头拧断后即表明终拧完毕，检查外露丝扣不得少于2 扣，断下来的卡头应放入工具袋内收集在一起，防止从高空坠落造成事故。

The initial tightening wrench should be able to control the torque, and the bolts after the initial tightening should be marked for confirmation. In order to prevent missing tightening, the high-strength bolts installed on the same day should be finally screwed on the same day. Special electric wrench shall be used for final tightening. Manual torque wrench can also be used in case of difficulties in individual operation, and final tightening torque shall be carried out according to design requirements. When using the electric wrench, the final tightening is finished after the bolt tail clamp is broken. Check that the exposed screw threads shall not be less than 2. The broken clamps shall be put into the tool bag and collected together to prevent safety accidents caused by falling from high altitude.