REMOVING A TOWER CRANE

Assembling and Disassembling Tower Cranes

Assembling a Modern Tower Crane Using High Reach Mobile Cranes

1. Foundation Preparation: The process begins with preparing a solid, level foundation for the tower crane base. This foundation is typically made of reinforced concrete to withstand the crane's weight and operational forces.
2. Base Erection: A mobile crane lifts and positions the tower crane's base onto the prepared foundation. The base is secured to the foundation using anchor bolts.
3. Mast Section Assembly: The mobile crane then lifts and places the first mast section (the vertical part of the tower crane) onto the base. Each mast section is typically several meters long and has a pin connection for attaching to the previous section. This process is repeated until the desired height is reached.
4. Slewing Unit Installation: Once the mast reaches the desired height, the mobile crane lifts the slewing unit (the part that allows the crane to rotate) and places it on top of the mast. The slewing unit is bolted or pinned to the top of the mast.
5. Jib and Counter Jib Assembly: The mobile crane is used to lift and attach the jib (the long horizontal arm) and the counter jib (the shorter horizontal arm) to the slewing unit. The jib is usually assembled in sections, with each section pinned or bolted together.
6. Counterweight Installation: Concrete counterweights are attached to the counter jib to provide balance and stability to the crane. The mobile crane lifts these counterweights and places them onto the counter jib.
7. Operator's Cab Installation: The operator's cab is lifted and attached to the top of the slewing unit, providing the operator with a clear view of the construction site.
8. Hoisting and Trolley Systems: The hoisting system (cables and pulleys) and the trolley (the mechanism that moves the load along the jib) are installed. The mobile crane may be used to lift and position heavier components.
9. Testing and Commissioning: After assembly, the tower crane is thoroughly tested to ensure all systems function properly. This includes checking the structural integrity, electrical systems, and safety devices.

Disassembly of a Tower Crane Using High Reach Mobile Cranes

The disassembly process is essentially the reverse of the assembly process:

1. Dismantling of Hoisting and Trolley Systems: The hoisting and trolley systems are removed and lowered to the ground using the mobile crane.
2. Operator's Cab Removal: The operator's cab is detached and lowered to the ground.
3. Counterweight Removal: The counterweights are removed from the counter jib.
4. Jib and Counter Jib Disassembly: The jib and counter jib sections are disassembled and lowered to the ground.
5. Slewing Unit Removal: The slewing unit is detached from the mast and lowered to the ground.
6. Mast Section Disassembly: The mast sections are disconnected one by one and lowered to the ground.
7. Base Removal: The crane base is detached from the foundation and lowered to the ground.

Important Considerations

• Safety: Safety is paramount during both assembly and disassembly. All personnel involved must be trained and follow strict safety protocols.
• Site Conditions: The construction site must be prepared with ample space for the mobile crane to maneuver and for temporary storage of crane components.
• Weather Conditions: Strong winds and adverse weather conditions can significantly affect the safety and feasibility of crane assembly and disassembly.

Please note that this is a general overview, and the specific steps and procedures may vary depending on the crane model and the specific site conditions.