Reliability of ductility requirements in concrete design codes

Ductility is an important limit state for the design of reinforced concrete beams. Its implementation varies considerably between design codes. This is investigated using reliability-based assessment with ductility defined by strain ratio. The modelling uncertainty for the ductility limit state typically is much greater than that for structural strength limit state. This is reflected in the corresponding reliability indices of limit state defined for ductility. Some of these could be considered unacceptably low.