What precautions should be taken during the use of a screw jack for lifting operations during bridge maintenance to ensure safe operation?

1. Conduct a comprehensive inspection of the jack before homework, and repair or replace it promptly if any abnormalities are found.

2. Choose a sturdy and flat ground to place the jack.

3. The jack should be uniformly lifted to avoid damage to the jack.

4. Pay attention to the lifting height and do not exceed the warning line.

5. The jack cannot support heavy objects for a long time, and other heavy objects should be used to support them after lifting.

The above are the precautions for using a screw jack for lifting operations in bridge maintenance. If you have any other questions, you can call for consultation.