A new hysteresis model for steel members

Since it is not economical to design structures to respond to earthquake loads in their elastic range, dissipation of energy by post-elastic deformation has been recommended. This requires an understanding of the hysteretic behaviour of structural members. A mathematical model is proposed for the hysteretic response of steel members. The model is based on a pre-de"ned skeleton curve, and consists of a linear and a non-linear region. The linear region is twice the elastic length on the skeleton curve, while the non-linear region is formed by superimposing an elliptical dissipation function on the skeleton curve. The shape of the proposed dissipation function and the hysteretic loops are compared with experimental results. Good agreement has been noted. Furthermore, it is shown that sti!ness degradation can be easily incorporated in the model. While the model can currently by used in the analysis of accumulated damages for steel structures, it has the potential to be extended to reinforced concrete structures, as well.