Precast bridge beams are among the heaviest single lifts carried out on construction sites. Individual beams can weigh in excess of 100 tonnes and must be lifted by mobile or crawler cranes, transported on specialist trailers, and placed to millimetre accuracy on prepared bearings. The lift often takes place over live roads, railways, or waterways requiring closures and complex coordination. A detailed lift plan, competent appointed person, and full exclusion zones are mandatory for every beam installation.
Key Hazards
Crane overturn from ground failure or exceeding capacity during heavy beam lifts
Beam dropping during lifting from rigging failure or incorrect sling configuration
Workers beneath the beam struck by the load or displaced by sudden beam movement
Traffic or rail disruption from beam lifts over live infrastructure below the bridge
Control Measures
Produce a detailed lift plan specifying crane configuration, ground bearing, and rigging arrangement.
Verify the exact beam weight from the manufacturer's data and include lifting accessories in the calculation.
Prepare the crane pad or platform to the designed specification with proven bearing capacity.
Establish full exclusion zones beneath and around the lift area before any beam leaves the ground.
Coordinate road or rail closures with the relevant authority and confirm the possession or closure window.
Use a tandem lift arrangement with detailed coordination procedures if two cranes are required.
Brief the entire lifting team including operators, slingers, and signallers before each beam lift.
Monitor wind speed continuously and postpone the lift if conditions exceed the plan limits.
Guide the beam into position using tag lines and never allow workers to reach under the suspended load.
Emergency / Rescue
If the crane shows signs of instability or the beam becomes uncontrollable, lower it to the ground immediately. Clear the exclusion zone. If the beam cannot be safely landed, evacuate all personnel and call for engineering assessment.
Remember
Precast bridge beams are among the heaviest single lifts and require meticulous planning.
Ground bearing capacity beneath the crane must be proven before the lift begins.
Exclusion zones must cover the full area beneath and around the lift including adjacent traffic lanes.
Tandem lifts using two cranes require specialist coordination and a detailed dual-crane lift plan.
Wind is the biggest variable in beam installation and the lift must stop if limits are exceeded.
No person may position themselves beneath a suspended beam under any circumstances.
Applicable Legislation: LOLER 1998 · BS 7121 (Safe Use of Cranes) · CDM Regulations 2015 · Health and Safety at Work etc. Act 1974