How to test the anti slip coefficient of high-strength bolts

1. Inspection batch regulations

 

Inspection batches can be divided according to the amount of high-strength bolts included in sub sub projects: steel structures with 50000 high-strength bolts are considered one batch, and steel structures with less than 50000 high-strength bolts are considered one batch.

 

2. Event sampling requirements

 

The test piece and the represented steel structural components should be of the same material, batch production, use the same friction surface treatment process, and have the same surface condition (including coating), stored under the same environmental conditions, and connected with high-strength bolts of the same batch and performance level.

 

3. Test equipment requirements

 

The error of the testing machine used in the experiment should be within 1%. The high-strength bolts, pressure sensors, and resistance strain gauges with resistance patches used in the experiment should be calibrated using a testing machine before the test, and their error should be within 2%.

 

4. Requirements for tightening bolts

 

Tightening high-strength bolts should be divided into initial tightening and final tightening. The initial tightening should reach about 50% of the standard pre tension value of the bolt. After final tightening, the pre tension value of each bolt should be within the range of 0.95p-1.05P (P is the design pre tension value of high-strength bolts).