EVALUATION OF DESIGN SPECTRA IN IRANIAN SEISMIC CODE

Design spectra that are presented in Iranian seismic code (standard No.2800-05) have been mainly based on the experiences of other countries such as seismic code of UBC, IBC and NEHRP provisions and European seismic code (Eurocode-8). Hence, they need to be improved with recent borehole-geotechnical data and strong-motion measurements for each period of time. Accordingly, extra studies should be devoted to examining the effect of strong motions on all site classes which are classified according to Iranian seismic code. In view of the strong data bank of geophysical and geotechnical investigations throughout Iran in IIEES (International Institute of Earthquake Engineering and Seismology) for over twenty years, the effect of the strong motions related to local tectonics of Iran on four site classes (Type I, II, III and, IV) is investigated. These new results, therefore, provide improving estimates of site-dependent response spectra for design spectrum. The results of this study reveal that the design spectra are represented in Iranian seismic code is considerably conservative that can lead to high cost of housing.This paper discusses ongoing studies of design spectra and amplification factors in accordance with new investigation that may influence future code developments.

کلیدواژه ها:

Strong Motion ، Site Class ، Response Spectra ، Design Spectra