Self-centring hybrid-steel-frames employing energy dissipation sequences: Insights and inelastic seismic demand model

This paper explored the seismic behaviour of self-centring hybrid-steel-frame (SC-HSF) employing energy dissipation sequences and the corresponding inelastic seismic demand model. The SC-HSF employing energy dissipation sequences was composed of the self-centring main frame (SCMF) and energy dissipation bays (EDBs). Two prototype structures were designed and developed using modelling techniques validated by experimental data. Nonlinear cyclic pushover analyses and nonlinear dynamic analyses were conducted to examine the seismic behaviour of the prototype structures. The seismic response of prototype structures including peak interstorey drifts and post-earthquake residual interstorey drifts were examined in detail. After verifying the promise of the SC-HSF structures, the energy factor for quantifying the inelastic seismic demand was developed by nonlinear spectral analyses based on the equivalent single-degree-of-freedom (SDOF) systems assigned with the structural hysteretic model. The effects of the structural hysteretic parameters on the mean and probabilistic features of the energy factors were discussed in detail. In addition, the lognormal distribution was selected to develop a probabilistic spectral seismic demand model based on a comparative study, and the prediction equations were developed to simulate the probabilistic features of the energy factors. Finally, the probabilistic spectral seismic demand model was used for evaluating the behaviour of the prototype structures, and the sufficiency of the model was justified.