Crane Assembly, Disassembly, and Climbing
Planning and direction
Erection, climbing, and dismantling are the highest-risk phases of a tower crane's life. Work must follow the manufacturer's manual, a site-specific assembly/disassembly plan, and the direction of a qualified assembly/disassembly (A/D) director. Rigging, crane used for assembly, personnel roles, exclusion zone, weather limits, and communication method are settled before the first bolt is turned.
Sequence fundamentals
Typical sequence: base and anchor section, then mast sections, then climbing unit or hydraulic climbing frame, slew assembly, cab, counterjib with hoist and ballast, jib, trolley and hook block, then ties/anchorage as required. Ballast is added in the order and quantity the manual specifies - premature or missing ballast creates an unbalanced condition. Torque structural bolts to spec and record it. Anchorage frames go in at the specified heights; free-standing height and tie spacing are hard limits that cannot be traded for convenience.
Climbing
Climbing is done in calm air within the manufacturer's wind limit, with the load landlocked, the jib balanced as the manual requires, the trolley parked, and nobody on the climbing frame except the trained crew. The hydraulic system, guide rollers, and latch pins must be verified at each stage.
Traps
the climbing unit; skipping tie levels; assuming a bigger hydraulic ram speeds the job safely.
Worked example
If the manual permits 30 m free-standing and then ties at 18 m intervals, the first tie must be installed before the mast top passes 30 m - so with 6 m sections, plan the tie at 24 m so the crane is never above 30 m unsupported.