Robustness assessment of a steel self-centering moment-resisting frame under column loss

The robustness of a seismically-designed steel self-centering moment-resisting frame (SC-MRF) under a column loss scenario is numerically assessed. The prototype SC-MRF is equipped with post-tensioned bars and optimised stainless steel energy dissipation devices. The SC-MRF was modelled in full detail using solid finite elements. The numerical model was calibrated using results from previous tests on post-tensioned beam-column connections and isolated component tests on the energy dissipation devices. Quasi-static analyses were carried out to identify the failure modes of the SC-MRF under a column loss scenario. Nonlinear dynamic analyses were also performed to evaluate the dynamic response of the frame and to assess the acceptance criteria against progressive collapse according to current formalised procedures. The results show that the SC-MRF has superior robustness and it can guarantee a high level of safety under a sudden column loss scenario due to the high fracture capacity of the stainless steel energy dissipation devices and the tie force resistance provided by the post-tensioned bars.