It was long ago stated by Priestley, and now applies more than ever, that the design of reinforced concrete is so full of myths, fallacies and contradictions that it is hard to know where to begin in an examination of current design. Such an examination forms the subject of the present paper, with a focus on current methods for designing stirrup arrangements for confining the transverse expansion of concrete in the compressive zone of the critical lengths of structural concrete members. These methods have often been found inapplicable in practice and the reason for this is attributed to the misconception that the structural performance code requirements can only be satisfied by confining the transverse expansion of concrete with an appropriate stirrup arrangement. It is argued that stirrups are required for securing a mechanism of load transfer, rather than for producing confinement, within the critical length when bond between concrete and steel is lost after yielding of the flexural reinforcement in tension. A method for assessing the stirrups required for this purpose is proposed and shown to produce design solutions that not only satisfy the structural performance code requirements but also are free of the shortcomings of current methods.

Deviation of the flexural reinforcement spacing from code specifications appears to underly the cause of the loss of bond (LoB) between concrete and steel that preceded the unexpected collapse of the top-floor balcony of a building under service load conditions on 15 October 2021 in Athens. Although rare, LoB has also been identified as the cause of collapse of buildings under similar conditions in the UK and Canada. However, the codes of practice for reinforced concrete (RC) design neither make reference to the effect of LoB on structural behaviour, nor include LoB in the parameters that the formulae currently used for assessing load-carrying capacity are dependent on. In view of this, a description of the effect of LoB on the function of RC beams is provided in this paper and this description is used as the basis for the derivation of a formula linking LoB with load-carrying capacity. The validity of the proposed formula is verified using published experimental information on the subject. The proposed formula is used for the structural assessment of the collapsed balcony, taking into account the design details, physical state and loading conditions of structural members similar to the one that collapsed.