Tower crane setup, erection, and dismantling support
The NC III operator supports the erection team; the erection supervisor and competent rigger direct the sequence. Your answers must show what you verify and what you refuse to do.
Before and during erection
- Foundation or ballast matches the approved drawing and the load chart's support condition; concrete strength confirmed before loading.
- Mast plumbness within the manufacturer's tolerance - commonly around 1/500 to 1/1000 of height - checked in two directions.
- Only the specified bolts, grade and length, clean threads, correct washers, torqued with a calibrated wrench in the manual's pattern; never substitute hardware.
- Pins, cotter pins, fishplates, tie bars, and climbing unit pins fully engaged and secured.
- Free-standing height and tie-in spacing never exceed the chart; ties installed before more mast is added.
- Wind monitored continuously; erection and dismantling stop at the manufacturer's limit (often 10–12 m/s at the jib) and in lightning.
Dismantling
Reverse the erection sequence exactly. Remove counterweights only as the manual permits, never all at once, and never release a tie before the mast is supported by the climbing unit.
Worked example
Mast height 40 m, measured plumb deviation 55 mm, tolerance 1/500. Allowance = 40 000 mm ÷ 500 = 80 mm. 55 mm is inside tolerance, so record it and continue; 85 mm would stop the job for investigation and re-plumb.
Traps
Reusing torque-to-yield bolts; tightening dry threads when the manual specifies lubricated; torquing in random order; adding mast above the free-standing limit “temporarily”; working in rising wind to finish a section.