Risk-targeted seismic design of reinforced concrete moment-resisting-frame buildings

The seismic design of new structures in Iran is currently based on earthquake hazard maps for a fixed return period of 475 years. However, this can lead to an unequal level of risk due to uncertainty in collapse capacity and differences in hazard curves in different locations. In the work reported in this paper, a risk-targeted approach was used to determine the peak ground acceleration (PGA) for designing reinforced concrete moment-resisting-frame (RC MRF) buildings in four important port cities in southern Iran. The three main parameters considered for determining risk-targeted PGA were the structural fragility curve, the seismic hazard curve and the target annual collapse probability. Nine RC MRF buildings with different geometrical characteristics were evaluated and their fragility curves were extracted. Then, using a risk integral, the annual collapse probability and PGA of the frames were obtained for the studied cities. Comparison of the results showed that an approach proposed in the literature for Europe is in accordance with the results of the approach proposed in this paper.