mainshock intensity effects on seismic fragility of rc mrfs under aftershocks

Rapid assessment of buildings after earthquakes and estimation of probable damage distribution due to the next strong aftershocks is important in seismic risk management procedure. in this paper, three code-conforming reinforced concrete moment resisting frames (rcmrfs) with 4, 8 and 15 stories, affected (damaged) by mainshock effects, are investigated for the probable failure due to aftershock effects. the frames are designed based on the last three editions of iranian code of seismic design of buildings referred as standard no. 2800 (std 2800). the frames are modeled in opensees finite element software. the performance level for collapse level of the frames was taken from iranian instruction for seismic rehabilitation of existing buildings, pbo-publication no. 360, 2007. assuming a log-normal distribution for failure probability function, corresponding values of median, μ and standard deviation, β, for each case are calculated and discussed. the results indicate that how the probability of failure in the seismic fragility curves may differ by changing the height of frames and design codes.