Improvement of the Seismic Behavior of Y-Shape Bracing using a Ductile Element, in Near Source Zone

Y-shape bracing is one of the common bracing systems in providing appropriate stiffness against lateral loads which is used in design or seismic rehabilitation of structures. This type of bracing system has some architectural advantages in comparison to most of the concentric braced frames; on the other hand, these braced frames have relatively low lateral stiffness with the potential of out of plane buckling; so this paper aims at reducing these weak points by introducing an energy absorbing element. The proposed element consists of a box and a ring which is placed near the connection of one of bracing elements to the gusset plate. This ductile element is primarily studied in commercial finite element software. By changing in its dimensions and surveying the resulted behavior, appropriate dimensions and their related nonlinear behavior is extracted and applied in other studies. Using these results, the presented element is placed in some two-dimensional y-shape braced frames and the improvement in the behavior of the bracing system under near source earthquakes is investigated through nonlinear dynamic analysis. The results show the appropriate effect of the proposed ductile element in seismic behavior improvement of the y-shape bracing.