Planning and Performing Lifts, Including Multi-Crane and Complex Lifts
The lift plan
Every lift needs a plan proportionate to its risk. A routine lift may use a standard procedure; a complex lift needs a documented lift study covering load mass and centre of gravity, rigging arrangement, crane position and configuration, capacity at all radii through the lift path, ground conditions, environmental limits, personnel roles and contingency. The plan must consider the full path, not just the pick and set points: the load may pass over structures, services or people. Percentage of capacity used is a common planning control; many sites set a threshold above which the lift becomes complex and requires greater scrutiny.
Multi-crane lifts
Tandem or multi-crane lifts are high risk because load sharing is dynamic and unpredictable. They require an engineered plan, matched crane capacity, a nominated supervisor, precise communication and a defined load share that keeps each crane within capacity at all times. As the load moves, the share changes; one crane can become overloaded. The trap is assuming a 50/50 split is safe; the plan must show the worst-case share. Never use two cranes to lift a load one crane cannot handle as a workaround.
Performing the lift
Confirm the load is free, rigging is correct, the exclusion zone is clear, signals are agreed, and the load moment indicator is functioning. Lift slowly, check for stability, keep the load under control with taglines, and never leave the controls with a suspended load.
Worked example
Two cranes share a 40 t load. The plan shows the worst case is 60/40, not 50/50. Crane A must therefore be rated for at least 24 t and Crane B for 16 t at the relevant radius, with margin.