Studies of the Ductility of Steel Structures

Part of the energy of an ultimate loading or of a severe earthquake shock is usually absorbed by the inelastic deformation of the structural frame. In order to assess the inelastic deformability of a steel frame and its ability to absorb energy, it is necessary to know the load-deformation behavior of its various components. The inelastic load-deformation response of beams, beam-columns, and beam-and-column subassemblages that are subjected to static unidirectional loading is examined. The relevent response criterion for a member is the end moment-end rotation relationship. It is shown, both from experimental and theoretical considerations, that the inelastic load-deformation behavior of many steel frames and frame components can be predicted and that, therefore, the energy absorption capacity of these frames can be assessed. Thus, the basis exists for a rational statical analysis and guidelines are provided for future dynamic studies.