چكيده به لاتين
The main goal of this research is to evaluate the seismic performance of the isolated steel moment-resisting frame with added damper under near field earthquake records. To achieve this goal, four, eight, and sixteen-story buildings were selected and their two-dimentional models were created in OpenSees software. For each frame with, six cases were considered, including a fixed-base structure, a structure with a triple friction pendulum bearing, and structures with an isolator and a damper with damping of eight, fifteen, twenty two and thirty percent. The models created under the three categories of the earthquake records including far field, near field without pulse and near field with pulse selected from the FEMA standard have been subjected to dynamic analysis and their important seismic responses including drift, the acceleration and shear force of the floors, the maximum displacement of the isolation system and the force created in the dampers were calculated and analyzed. Also, the collapse performance of the models mentioned above was checked using the method introduced in the FEMA standard. For this purpose, incremental dynamic analysis (IDA) was performed for each of the models under three categories of earthquake records, and their collapse margin ratio (CMR) and adjusted collapse margin ratio (ACMR) were calculated and compared and evaluated with the standard permissible values. The results show that the use of a damper has led to a reduction in the displacement of the isolation system, which is one of the goals of this research, but with the increase of the damping, the response of the superstructure has increased. But the combination of the isolator with the viscous damper with eight percent damping has also led to a reduction in the displacement of the isolators and has not caused a significant increase in the seismic responses. Also, the collapse performance of the models used under different earthquake categories has been different, which has been evaluated in this research.
