Seismic Performance of Eccentrically Brace Frames with Steel Shear Panels and Optimum Rotational Friction Damper at Different Seismic Levels

Today, with the advancement of analysis and structural design, various lateral force resisting systems have been proposed to take advantage of each of the existing systems simultaneously. Among bracing systems, Eccentrically Brace Frames are the top priority. The application of energy dissipation, such as friction dampers and shear panels, reduces seismic responses to earthquake and wind. In the present paper, a system consisting of an Eccentrically brace frames with a steel shear panel and a rotation friction damper has been proposed based on numerical modeling and its performance is based on different levels of Hazard level. Hazard level, with average return periods of 72, 475 and 2475 years, has been studied by dynamic analyzes of nonlinear time history. The Optimum slip moment is determined based on the minimum value of the seismic performance index, in three levels of danger, once separately and once by considering the level of intermediate Hazard level, with a return period of 1200 years. To investigate the seismic performance of the proposed structural system, the structural responses are estimated at three hazard levels based on the optimal slip moment determined by the two states. The results showed that considering the Optimum slip moment corresponding to each Hazard level separately, improves the seismic responses of the proposed structural system. But naturally, the Optimum slip moment shared different hazard levels will provide conservative results . It was also found that the damper, at higher hazard levels, has a better performance in improving the response and seismic behavior of this hybrid system.