Date of incident: September 2024
Notice of incident number: 2024171900010
Employers: Concrete services company; rebar manufacturer

Incident summary
Workers at a commercial building construction site were preparing and hoisting loads of formwork panels (moulds for concrete). A load of panels being hoisted by a tower crane fell from approximately 3 m above the ground. Two workers were injured by the falling panels.

Investigation conclusions

Cause

• Pins in lifting bracket were inverted. The stack of eight formwork panels was being hoisted using a lifting bracket with chains and four lifting pins inserted into holes on the bottom panel of the stack. The lifting bracket was assembled incorrectly — the shackles were connected on the wrong side of the lifting pins. This meant that the lifting pin’s retaining hooks, the only locking feature in the lifting bracket’s design, were rendered useless once tension was applied to the lifting bracket chains, because the pins rotated in their respective holes. With the pins inverted, the retaining hooks could not latch onto the inner edge of the pin hole, and one of the pins slid out from the formwork panel’s pin hole.

Contributing factors

• Unreliable lifting bracket design. The design of the lifting bracket is unreliable, as it lacks any visual indication of the correct orientation of the shackles on the lifting pins or of whether the pins are inverted or otherwise incorrectly inserted. The only controls in place to prevent the pins from being assembled and used in the inverted position were instruction and training.
• Load over working load limit of lifting bracket and improperly configured. The load that fell exceeded the working load limit of the lifting bracket by 6%. In addition, several corner formwork pieces were stacked on top of the panels during the lift and were protruding to the side, which changed the angle at which the tension was applied to the lifting pin that slid out. The change in angle created an outward force, increasing the likelihood that the inverted pin would slide out of the hole.

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