Seismic fragility curves for mid-rise RC frames designed according to Iranian seismic code

The uncertain nature of future ground motions is leading to development of probabilistic structural damage estimation procedures. Fragility curves are useful tools for showing the probability of structural damage due to earthquakes as a function of ground motion indices. The contribution of this study is to develop the fragility curves for mid-rise RC frames designed according to the Iranian Seismic Design Code. These structures constitute the most vulnerable construction type in Iran well as several other countries prone to earthquakes. Sample 4, 6 and 8 story buildings were designed according to the Iranian seismic code. Incremental nonlinear dynamic analyses were performed for these sample buildings using ten near-fault ground motions to determine the maximum inter-story drift ratio. Based on those ratio fragility curves were developed in terms of peak ground acceleration for immediate occupancy and life safety damage levels with lognormal distribution assumption. The results show that sample frame structures do not satisfy performance objectives of Standard No. 2800.