Risk-targeted seismic design maps for Iran

Iran is located in a very high seismic zone. The current national code of design of buildings referred to as Standard No. 2800 (STD-2800) employs the design-basis earthquake (DBE) based on the uniform hazard philosophy. New generations of seismic codes and related researches have used a uniform risk philosophy instead, where the parameters are defined in order to provide a tool for designing the buildings with equal or at least harmonized collapse probability across the country. In this paper, a risk-targeted seismic design map has been developed for Iran. A seismic hazard model developed by EMME14 project was used for this purpose. A generic collapse fragility function was used, the parameters of which were selected based on sensitivity analyses. Taking into account the seismic hazard model from the EMME14 project, the risk of collapse of the buildings in Iran was calculated once for DBE values provided by STD-2800 and again with the DBE values resulted from the EMME14 model. An acceptable risk level of 1% in 50 years was considered then, to estimate the map of distribution of risk coefficients as well as the map of collapse risk for the buildings in the country. The results show a large dispersion in the risk of collapse across the country, in both cases. Finally, the risk-targeted seismic design map for the country is presented.