Evaluating the effects of torsional irregularity on the seismic life-cycle cost of steel moment-resisting buildings under near-field and far-field earthquakes

This study is concentrated on the seismic life-cycle cost (SLCC) evaluation of irregular steel moment-resisting buildings. To do so, twenty near-field records (including pulse-like and non-pulse-like records) and twenty far-field records are selected, and incremental dynamic analysis is performed. The seismic fragility analysis and SLCC are conducted based on the performance- and cost-based methods. Also, a variety of uncertainties such as record-to-record, modeling, and determining the limit states are considered. The results indicate that first, the presence of torsional irregularity has caused an increase of up to 992% in the SLCC of the case buildings. Second, the difference between the SLCC of the case buildings under the near-field and that of the buildings under the far-field records is found up to 42%. However, the difference between the exceedance probability from the limit states of the buildings under the near-field records and that of the buildings under the far-field records is found negligible. Last but not least, the results indicate that as the height of the buildings increases, the record-to-record uncertainty increases as well. All in all, this study illustrates that cost-based fragility and SLCC evaluation of buildings can lead researchers to obtain a reliable understanding of the seismic damages and performance of the buildings.