Jacking is an important work in the use of Tower Crane, and is also an accident-prone stage. Only by making full preparations and take the announcements during and after the completion of the construction, can we ensure the smooth progress of the work.
There are some special notice for tower crane jacking:
1. Preparatory work before jacking of tower crane
- Prepare the mast sections to be added according to the required raising height of the tower, and line masts up along the jib.
- The on-site staffs in charge of jacking in their place according to the duties.
- Check whether the hydraulic system works normally, ensure that the pressure of hydraulic oil is in line with the regulations, the expansion of the piston rod is stable without jam phenomenon.
- Check the condition of jacking beam and hanging plate.
- Adjust the clearance between jacking guide wheel and tower main chord to meet the requirements.
- According to the manual, lift one Mast Section to be added to the imported beam, and then lift another mast section, move the luffing trolley to find balance and lock the Slewing Mechanism.
2. Matters needing attention during jacking
- During jacking, special personnel should be in charge of the command, special personnel in charge of taking care of the power supply, special personnel in charge of operating the hydraulic pump, special personnel in charge of supporting the jacking beam, special personnel in charge of pulling climbing claw, special personnel in charge of installation of the mast section. All personnel must concentrate, follow instructions and stick to their posts.
- Jacking work is not allowed at night. In special cases when jacking must be carried out, adequate lighting must be provided.
- Jacking work is strictly prohibited when the wind speed exceeds level 4 or the speed specified in the manual. During the jacking process, in case of sudden wind, jacking work should be immediately stopped.
- During jacking, do not rotate the jib and operate the trolley.
- Jacking work must be stopped immediately for inspection in case of jam or other fault. If the fault is not eliminated, jacking shall not be continued.
- The operator must concentrate on the operation, do not put his head into the scope of imported guide wheel, so as to avoid injury from sudden movement of the mast section.
- Pay attention to check the required releasing length of cable, and strictly prevent cable from being pulled, jammed and squeezed in the process of moving.
- The newly introduced mast section must be firmly connected with the upper and lower tower before the next continued jacking operation
3. Matters needing attention after jacking
- Check and tighten the height bolts connecting upper and down towers.
- Check whether the operating handle of the hydraulic system has been set to zero position.
- Check and put off the power of hydraulic jacking system.
- Remove the mast section used for balance on sling steel , and start the locking condition of slewing mechanism.
