In this study, the performance and efficiency have been investigated of friction damper in semi-active control mode in structural responses under the influence of Chichi, Kobe, Tabas and Gazli earthquakes in the near field. Semi-active friction dampers made up of two plates that are slipping over. The contact force between the pages is changed according to the order of the control algorithm and the force on the structure is adjusted at any time during the earthquake. The LQR control algorithm and the shear control rule have been used to determine the contact force at any given moment. A structural ten-story steel X shape bracing system in both directions under dynamic analysis for numerical studies selected and subjected to vibration 4 earthquake specifications and content of different frequency in software Etabs to obtain matrices of mass and stiffness and Matlab to evaluate the different states of being The damper has been investigated. Structural responses in all classes is determined and compared. The results indicate that the use of a friction damper leads to a reduction of displacement, In the mode of using the damper in a semi-active control mode, it is better than active or inactive mode. The damper layout is also examined in four modes, which shows that the use of the damper around the structural plan is better. For example, the base shear when the damper is in around the plan, In active and inactive control mode, it has increased by 41.4% and 84.86% relative to the semi-active control status

Investigation on Seismic Behavior of Steel Frames with semi-active Rotational Friction Dampers
Hadi Bahri

