Worker Pinned by Fallen Wall Formwork Panel

On 23 January 2015, four workers were assembling wall formwork panels to prepare for subsequent casting of a wall. While they were adjusting the tie rods, an 11-metre rebar cage that had been installed nearby tilted towards the wall formwork panels. This caused the formwork panel to fall inwards, pinning one of the workers between the formwork panels. The worker was rescued and conveyed to the hospital, but he succumbed to his injury subsequently. The other three workers escaped unhurt.

Figure 1: Overview of accident scene

Recommendations*

1. Stability of the rebar cage Always calculate the slenderness ratio of the rebar cage to determine the safe free-standing height. Fabricate the cage in shorter lengths where possible e.g. 5-metre cages instead of 10-metre cage.To mitigate the instability of the standing rebar cage, provide proper designed support systems such as steel props and/or guy wires. These support systems should be inspected regularly to ensure that they are not removed or have weakened.                                                Figure 2: Support systems – guy wires and steel prop. 2.Formwork safety Formwork panels should not be left in free-standing position. Stable positions can be attained by securing the formwork using tie rods, additional steel props or anchor ties. If the formwork is hoisted into position, it should be adequately secured prior to the release of the lifting hooks to prevent accidental toppling.  The Professional Engineer (PE) who designs the formwork structure shall ensure that its construction or assembly can be executed safely. PEs involved in formwork-related activities are reminded to pay attention to formwork safety, so that workers will not be at risk of any accidental collapse. 3.Work coordination and communication Proper work coordination should be established for the different work activities within the worksite, especially when works are being carried out in a constrained environment. To ensure the better management and coordination of work activities, safe work methods and procedures should be established, communicated and implemented. A permit-to-work (PTW) system should also be put in place to control hazardous work and/or simultaneous activities at the site. The PTW sets out the precautions required to complete the work safely, and serve as a means of communication between the site management and personnel.

4. Risk Assessment Conduct thorough Risk Assessments (RAs) for all work activities to manage any foreseeable risk that may arise. The RAs should look into the following areas, but not limited to: Placement of rebar cage Support for rebar cage Assembly of formwork Formwork structure stability Working at height Emergency response and recover Source: www.wshc.sg