Effect of reinforcement type on the ductility of suspended reinforced concrete slabs

Reinforced concrete slabs typically have relatively small tensile reinforcement ratios and are generally regarded as very ductile structural elements. This is not the case for slabs reinforced with low-ductility welded wire fabric. Such slabs fail with little warning by fracture of the reinforcement in a brittle and catastrophic manner and, as a consequence, many of the assumptions implicit in structural design are not applicable. Slabs containing low-ductility reinforcement lack robustness and cannot absorb the energy required to resist significant impact or blast loading. This paper outlines the importance of ductility in concrete structures and describes the observed failure mode and ductility of reinforced concrete slabs containing both normal and low-ductility reinforcement. For slabs reinforced with low-ductility welded wire fabric, failure is characterized by relatively little plastic deformation prior to collapse, with small rotational capacities of the critical regions and, consequently, little moment redistribution.