COMPARISON OF SEISMIC RISK OF LOW RISEIMPORTANT BUILDINGS DESIGNED BYDIFFERENT EDITIONS OF IRANIAN SEISMIC CODE

Buildings with high degree of importance and facilities such as hospitals, police stations, fire stations and other vital facilities play crucial role in crisis and risk management of cities. Therefore special attention has been paid to design and construct these buildings in order to maintain their performance during and after the earthquake. Design of important building in Iran is conducted based on the Iranian code of practice for seismic resistant design of buildings (ISC). Since the first lunch of ISC, three editions of ISChave been introduced. In this study, improvement of seismic safety of important buildings in different editions of ISC are examined and the results are compare that with acceptable level of safety. In this study, a very important 3-story steel moment resisting frame is selected and designed base on different editions of ISC for high seismic zone. The seismic fragility functions of buildings are estimated in all four soil classifications. The probability of failure of frames are estimated for Tehran and Tabrizwhere are two major citieslocated in high seismic zones. Results shows a good improvement in safety of different frames in recent editions of ISC, especially from first to second edition. However, the functionality and safety of buildings were not satisfy the minimum requirement of the code. In addition the probability of failure of frames located in softer soil types is higher than others.This indicated that within any code edition, a constant limit of safety was not provided indifferent soil types.