Hossein Tajmir Riahi - Assistant Professor, Department of Civil Engineering, University of Isfahan
Setare Seyedain Boroujeni - Graduated Student, Department of Civil Engineering, University of Isfahan

Most recent seismic codes include response modification factor in the definition of equivalent lateral forces to reduce the linear elastic design spectrum to account for energy dissipation capacity of structure. In this paper, application of Endurance Time (ET) method in nonlinear seismic analysis has been investigated. A set of three acceleration functions have been applied to various steel moment resisting frames and derived results are compared to Incremental Dynamic Analysis (IDA) results. ET analysis results accuracy in evaluation of response modification factors has been assessed according to frames performances evaluation and compared to IDA accuracy in this regards. It is observed that the response modification factors resulted from ET analysis are compatible with those obtained from IDA in most cases. Considering the great amount of computational efforts that should be done for evaluating response modification factors by IDA, ET analysis can reasonably evaluate them with less analysis

Response modification factor, Endurance time analysis, Steel moment-resisting frame, Incremental dynamic analysis