Collapse of reinforcement bars during culvert construction

Background

WorkSafe attended an incident where several 4.5-metre-high steel reinforcement bars collapsed at a construction site in Melbourne’s north-east. The bars, which were set up to form a seven-metre-high culvert, spanned about 25 metres. Although temporary bracing was used to support the bars, there was no formal design for this bracing. There were no injuries.

Safety issues

Steel reinforcement bars can be heavy. If the bars are not adequately supported or braced, they can become unstable and collapse, posing a serious risk to nearby employees and the public.

Recommended ways to control risks

When using temporary bracing or other stability controls, employers should ensure a safe working environment by:

• identifying hazards and risks related to steel reinforcement stability
• adequately bracing or supporting enforcing steel for vertical structures
• engaging a competent person, such as a temporary works engineer, to design temporary bracing, prior to formworking and concrete placement
• using appropriate equipment for support or bracing
• providing adequate information, instruction, training or supervision for employees for the installation and removal of temporary bracing
• having a suitably competent person verify that the temporary bracing has been installed in accordance with the design

A competent person should also regularly assess the stability of the structure while temporary bracing or supports are being used. If changes need to be made to the temporary bracing design, ensure:

• a competent person checks that the changes are safe, and
• the design plans or drawings are updated to reflect those changes.

Legal duties

Under the Occupational Health and Safety Act 2004, employers must:

• So far as is reasonably practicable, provide and maintain a working environment that is safe and without risks to the health of employees and independent contractors.
• Provide or maintain plant or systems of work that are safe and without risks to health, so far as is reasonably practicable.
• Provide employees with the necessary information, instruction, training or supervision to enable them to do their work in a way that is safe and without risks to health
• Consult with employees, including any health and safety representatives.