Ductility of steel structures: The model of interactive hinge

Before the 1960s the ductility notion was used only for characterizing the material behaviour. After Baker's research on plastic design, this concept has been extended to the structural level. This paper provides a general overview of ductility. The paper examines the behaviour of material ductility, cross-section ductility and member ductility separately, then it studies how the sum of the effects of all these ductilities affect the structural ductility. The effect of the different ductilities can be built into the structural behaviour through an interactive hinge model. The model of the interactive hinge also takes into consideration the effects of the residual stresses and deformations, the strain hardening and the plate buckling