energy absorption and inelasticity distribution mechanisms in steel moment frames affected by mainshock-afershock sequences

This study evaluates the effect of earthquake shock sequences on plasticity and hysteretic energy distribution of special steel moment frames (ssmfs). for this purpose, two 4- and 12-story ssmfs are numerically modelled in opensees and subjected to incremental dynamic analysis (ida). these analyses aim to capture the collapse state of structures under aftershock events preceded by mainshocks. the distribution of maximum ductility demand (mdd) and energy absorption contribution (eac) at the collapse state is then evaluated in presence of mainshocks with varying intensities. the results show that taller building are much more affected by a prior mainshock damage due to significance of p-delta effects in presence of residual deformations caused by the mainshock.