Effect of Infill Plate and Lateral Bracing on Cyclic Behavior of Eccentrically Braced Frames with Double Vertical Link

Due to occurrence of plastic deformations in horizontal link beam in Eccentrically Braced Frames (EBF), Performance of structure after Earthquake is disrupted and replacement of horizontal link beam is time consuming and need to cost. Using vertical link beam is one of the solutions to expedite structural performance after earthquake. Double vertical links are one of the new methods in EBFs that have been considered by the researchers. The aim of this paper is assessment of EBFs with longer links with flexural-shear interaction and flexural response and improvement of behavior with adding infill plate between two vertical link beams. For this reasons, after verification of modeling using finite element software, 6 specimens have been modeled in software with different specifications like vertical link beam length, infill plate and yield stress of infill plates. Initial assessments of models are carried out using nonlinear static analysis to more insight of response and changes in behavior. Thickness of infill plate is selected based in occurrence of plastic deformations in vertical link beams and avoid brace buckling during static nonlinear analysis. After nonlinear static analysis, cyclic loading is applied to 6 model based on AISC loading protocol. From cyclic loading of structures some crucial curve and parameters is extracted in different drift ratio like cyclic force, push curve, dissipated energy, secant stiffness, equivalent damping ratio. The results show in the frames with flexural-shear interaction response of link beams and infill plate, stable force displacement is observed under cyclic loading until drift ratio between 0.05 and 0.06 and for frames with flexural response of link beams and infill plate, stable force displacement is observed under cyclic loading until drift ratio between 0.06 and 0.07.