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CROSS Safety Report

Boom MEPW falls through precast planks

Report ID: 359 Published: 1 April 2013 Region: CROSS-UK

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A high injury potential near-miss (near hit) incident occurred when a mobile elevated working platform (MEPW) fell through a floor at a point where there was a notched precast plank.

Key Learning Outcomes

For the construction team:

  • It is good practice to carry out a risk assessment and method statement (RAMS) for all construction activities. This can ensure the sequencing of work activities are properly considered and planned.

  • Having a competent temporary works designer/adviser in place to supply an engineered solution can ensure all temporary works are carefully considered and planned

  • Verification of temporary works erection by a competent person who can oversee and coordinate the whole process can also ensure the works are installed correctly

Full Report

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The Full Report below has been submitted to CROSS and describes the reporter’s experience. The text has been edited for clarity and to ensure anonymity and confidentiality by removing any identifiable details. If you would like to know more about our secure reporting process or submit a report yourself, please visit the reporting to CROSS-UK page.


An alert was provided by a contractor to publicise the measures to be taken on sites where precast concrete floor planks are installed and may be loaded with plant or materials before an in-situ topping is cast. A high injury potential near-miss (near hit) incident occurred when a boom MEPW fell through such a floor at a point where there was a notched precast plank.  

The plank failed because of installation and quality errors which could potentially have resulted in the MEWP and operator falling through multiple floors of the structure. The incident was fortunate to result only in property damage.

Where possible, it is recommended, says the reporter, that the works are programmed so that the structural topping is applied and cured, prior to loading the deck with plant or materials for subsequent operations.

All plank installations should be reviewed to ensure they are compliant with designer’s requirements and specification, and Quality Assurance inspections are completed in-process with the required timing, rigour and diligence.

Expert Panel Comments

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Expert Panels comment on the reports we receive. They use their experience to help you understand what can be learned from the reports. If you would like to know more, please visit the CROSS-UK Expert Panels page.

The critical point here is that the plank was notched and there have been previous failures due to this cause. It is often necessary to notch the plank at the support where the column passes through the floor. However, as the planks have no lateral reinforcement, they are not able to redistribute loads effectively so notching has a significant weakening effect on shear capacity. For this reason, it may be prudent to provide an angle or other member on the column to support the edge of the notched panel.

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