Extension of the improved upper-bound pushover analysis for seismic assessment of steel moment resisting frames with setbacks

Pushover analysis technique is a key tool for the performance-based seismic design that has been largely adopted in new generation of codes. Therefore, more precise and reliable performance predictions are highly demanded. Improved upper-bound (IUB) pushover one advanced nonlinear static procedures (NSPs) recently developed. This procedure adequately estimates response regular tall buildings. In this study, IUB extended to assess irregular buildings with setbacks. To end, an adjustment lateral load distribution implemented by integrating third mode vibration control these complex Fifteen multi-storey steel frames different types setbacks including reference structure used test accuracy proposed comparing its results those from other NSPs time history (NTHA). The findings show superior capacity predicting levels