Seismic performance of a self-centering steel moment frame building: From component-level modeling to economic loss assessment

The seismic performance and economic seismic losses of a 6-story self-centering moment resisting frame (SC-MRF) building using post-tensioned (PT) connections with top-and-seat angles is evaluated. A phenomenological model that captures the lateral load response of PT connections is developed and verified using previous experiments. A 2D model of the 6-story SC-MRF is constructed in OpenSees using the newly developed phenomenological model. Using the same member sizes as the SC-MRF, a model is also created for a welded moment resisting frame (WMRF) with reduced beam section (RBS) connections. Nonlinear static and incremental dynamic analyses are performed on the SC-MRF and WMRF models. The lateral load carrying capacity of the SC-MRF is found to be 40% lower than that of the WMRF. The dynamic analysis results show that the WMRF has higher collapse resistance, whereas the SC-MRF undergoes smaller residual drifts. Finally, the earthquake-induced economic impact to the two buildings is assessed using the FEMA P58 methodology, where the expected annual loss for the SC-MRF is computed to be 21% higher than that for the WMRF building. More specifically, the SC-MRF building (with PT connections and top-and-seat angles) has a lower expected loss associated with excessive residual drifts but higher collapse losses.