WorkSafe Victoria recently issued a safety alert highlighting the dangers of using unmarked lifting, bracing and fixing inserts in concrete following an incident where a bracing insert embedded in a precast concrete panel failed while the brace fixing bolt was being tightened into the insert.
The safety alert noted that the failure of a bracing insert may lead to the immediate collapse of concrete panels, and crush any person in the immediate vicinity.
In the incident, the bracing insert (otherwise known as a ferrule) snapped approximately 6cm inside the panel at the hole designed for the placing of an anchor bar, and the top part of the ferrule pulled out of the concrete.
The ferrule contained no marking as recommended by section 2.4.1 of AS3850 – Tilt-up concrete construction, and the alert noted that markings of insert ferrules are important so the lifting capacity of the ferrule can be related to the suppliers’ brochures and test reports.
The safety alert recommended a number of control measures and said panel manufacturers should ensure:
only bracing inserts that have been appropriately designed and tested in accordance with AS3850 are used
the inserts are marked with the manufacturer’s name or symbol
only inserts specified by the design engineer are used, unless the engineer approves (in writing) a different insert
the placement of the inserts are in accordance with the approved shop drawings, and certified as such, before pouring concrete
they provide a copy of the supplier’s technical information, including the working load limit (WLL) of the insert, to the end users