Purpose <p>The study investigates the seismic performance of base – isolated frames using the capacity spectrum method, focusing on three segments of the capacity curve: elastic, elastic-plastic, and near-collapse states, under both main and aftershocks. Far-field and Near-field earthquakes are considered to ensure applicability to realistic ground motions.</p> Methods <p>Performance points at the three states are identified with the help of capacity curves obtained by pushover analysis for both undamaged and damaged structures after each shock. The demand curves required for obtaining the performance points are determined from the response spectrums of the suits of earthquakes used in the analysis including main-shocks and aftershocks.</p> Results <p>Seismic demand parameters, namely, base shear (BS), top-storey displacement, effective time period, and equivalent damping, are evaluated at these points for suits of far field and near field earthquakes, including aftershock effects.</p> Conclusion <p>Comparisons between damaged and undamaged states show that while base shear decreases slightly with successive aftershocks, top-storey displacement of the damaged structure increases sharply, highlighting its vulnerability under repeated seismic demands.</p>