Background/Introduction <p>Since displacement has a direct correlation with structural damage potential, seismic design codes impose various limitations to prevent serious human injury. Lack of adequate structural regularity can seriously affect these limits especially in consecutive shocks. Although dual LCF systems may have been investigated in previous studies, the effect of geometric irregularity and displacement-dependent response of these systems under successive earthquakes has not been evaluated so far.</p> Purpose <p>This study tries to evaluate the effect of irregularity on displacement-depended responses of steel frames with dual LCF under successive earthquakes.</p> Methods <p>Twelve regular/irregular steel frames with shear/flexural linked beams were designed and analyzed under critical successive earthquakes. The inter-story drift, residual displacement, and ductility demand were extracted and compared for 3, 6, and 9 story frames.</p> Results <p>The results indicate significant effect of seismic sequence phenomenon on increased ductility demand because this increase was observed to more than 2.6 times in 3 -story frame. Moreover, the better performance of the shear linked beams in controlling/reducing the ductility demand has been observed, whether in both consecutive and irregularities. This decrease was 2, 2.5, and 4 times for the 3, 6, and 9 story frames, respectively. Additionally, this demand was felt in the upper stories, especially for flexural behavior in all studied models.</p> Conclusions <p>Dual LCF system effectively reduced the ratio of increased residual drift due to seismic sequence in irregular versus regular configurations. Flexural linked beams led to smaller increases in inter-story drift in both regular and irregular models. Finally, mathematical equations were proposed to estimate the average increased ductility demand due to irregularity under successive scenarios to single earthquakes.</p>