Arjomandi - Graduate Research Assistant , Department of civil engineering, Sharif University of Technology, Tehran, Iran
Estekanchi - Associate Professor, Department of civil engineering, Sharif University of Technology, Tehran, Iran

Past engineering experiences have shown that the popular design methods have some weaknesses when considering the performance based design concepts. In order to overcome these weaknesses various guidelines have been proposed. Although the Performance Based Earthquake engineering is popular to reassess and rehabilitate the existing structures, it has not found its place in popular design methodologies and building codes. In this paper, by using the concepts of “damage spectra” and “performance levels” introduced in FEMA-356 guideline, some damage spectrums have been developed that can be used to define the applicable lateral load on the structure as an alternative to the response spectrums proposed by popular building codes. These damage spectrums help engineers to design structures with any required performance level. The comparison between these damage spectrums, Iran standard 2800 response spectrum and NEHRP 2000 gives a good insight to engineers. In generating these damage spectrums some assumptions have been made which are presented and discussed in detail. At last, the performance levels of some sample steel moment frames under the base earthquakes used in generating damage spectrums are assessed using nonlinear time history analysis as proposed in FEMA-356 guidelines and the results are compared with the proposed method.