Tandem lifts use two or more cranes to lift a single load and are among the highest-risk lifting operations on any construction site. The load sharing between cranes changes dynamically during the lift, and a failure by one crane can overload the other catastrophically. These operations require detailed planning, experienced personnel, and strict coordination throughout.
Key Hazards
Catastrophic overload of one crane if the other fails or moves unexpectedly
Uncontrolled load swing from uncoordinated crane movements during the lift
Communication breakdown between crane operators causing timing errors
Rigging failure from uneven load distribution across the lifting points
Control Measures
Prepare a detailed engineered lift plan specific to the tandem lift signed off by an appointed person.
Ensure both cranes are rated for their share of the load plus a suitable safety factor.
Appoint a single lift supervisor with overall control and direct communication to both crane operators.
Conduct a full rehearsal briefing with all personnel covering the lift sequence and abort procedure.
Use matched sling lengths and rigging arrangements to maintain even load sharing between cranes.
Establish exclusion zones covering the combined operating radius of both cranes during the lift.
Maintain continuous radio communication between the lift supervisor and both crane operators throughout.
Monitor crane load indicators on both machines throughout every phase of the lift operation.
Do not proceed if wind speed exceeds the lower of the two cranes' specified wind speed limits.
Remember
A detailed engineered lift plan must be prepared and signed off by an appointed person
A single lift supervisor must have overall control and direct comms with both crane operators
Both cranes must be rated for their load share plus adequate safety factor at all radii
Continuous radio communication must be maintained between the supervisor and both operators
Wind speed limits are set by the lower-rated crane and must not be exceeded during the lift
Applicable Legislation: LOLER 1998 · BS 7121 (Code of Practice for Safe Use of Cranes) · CDM Regulations 2015 · Health and Safety at Work etc. Act 1974