Erection, Climbing, Jacking and Dismantling
Erection and dismantling are the highest-risk phases for self-erect cranes, and questions focus on sequence, supervision and stability during transition.
Planning
- A method statement and risk assessment specific to the crane model, site and sequence; generic documents are insufficient.
- A competent person supervises, with trained operatives and a planned exclusion zone.
- Wind speed checked against the manufacturer's erection/dismantling limit - often lower than the in-service limit.
Sequence principles
- Ballast is placed in the sequence the manufacturer specifies; incorrect ballast sequencing has caused collapses.
- During climbing/jacking, the crane passes through configurations that are not covered by the normal load chart and may be less stable; the manufacturer's climbing procedure must be followed exactly, including any temporary support or anchoring.
- Pins and bolts fully fitted and secured before load is transferred; never rely on partial connections.
- After climbing, the crane must be re-commissioned: inspections, limit switch checks, and thorough examination where required.
Dismantling
Reverse of erection, with the same supervision and wind limits, plus a plan for lowering and removing sections and ballast.
Traps
- Assuming the in-service wind limit applies during erection - it usually does not.
- Believing a climbing operation can be paused indefinitely in a partially climbed state without assessing stability.
- Forgetting that limit switches may need re-setting after climbing.