Site Preparation, Erection, Climbing, and Dismantling
Site Preparation, Erection, Climbing, and Dismantling
Site preparation for a tower crane involves foundation design (often a reinforced concrete pad or ballasted base), soil bearing capacity verification, and levelness. The crane must be free from obstructions and have a clear slew path. Erection and dismantling are high-risk operations requiring a method statement, lift plan, and competent personnel. Climbing (for climbing cranes) uses a climbing frame and hydraulic rams; the process must be done in calm wind (typically below 10 m/s or manufacturer's limit) and with the crane balanced.
Traps in exam questions include: assuming erection can proceed in any wind; forgetting that dismantling is reverse of erection but often more hazardous due to site conditions; and confusing climbing with jumping (same process). Another trap: the foundation must be designed for the maximum in-service and out-of-service loads, including wind. Always check that anchor bolts are torqued and pendants are correctly tensioned.
Worked example / rule of thumb: Before climbing, verify the wind speed at the jib height is below the manufacturer's limit (often 10 m/s). Use a checklist for each stage: foundation cured, mast plumb, pins secured, limit switches tested. A good rule: no climbing or erection without a documented lift plan and a qualified supervisor.