Rebar stability

There have been a significant number of accidents involving the collapse of in situ fixed reinforcement cages and prefabricated reinforcement assemblies during their temporary works life cycle, which have led to fatalities and serious injuries (Figures 32.1 and 32.2). Currently there is limited guidance on this subject. Advancements in the design, detailing and assembly methods of reinforcement have also influenced cage stability. Traditionally the design and detailing of reinforcement was the preserve of the PWD, however it is now frequently the responsibility of the principal contractor or a specialist subcontractor and detailer. The design methodology and analysis have been refined and the amount of reinforcement has been rationalised. This can often lead to smaller diameter, slender reinforcement, hence reducing cage stability. Those responsible for design optimisation might not have sufficient practical site experience to identify fixing risks, including temporary stability of reinforcement.