Determination of hysteretic behavior of bucklingrestrained braces in frame system

If the lateral forces induced by earthquakes or winds affect to the structures, the steel brace members yields under the effect of axial tensile demands. On the other hands, the steel braces buckle due to axial compression demands and then their axial capacity decreases significantly. The lateral load and energy dissipation capacity in addition to lateral stiffness of braced structures suffer from buckling of the brace members significantly. Due to buckling of the brace members, the unstable hysteretic behavior of the structures results in severe damages or collapse. For this reasons, the buckling restrained braces (BRBs) has become as an attractive research topic for researchers in recent years. The BRBs have mainly two parts namely casing member and core plate. The casing member provides stability to the core plate when the BRBs are under compression demands. In this study, three BRBs with different cross-sectional areas of core plates and different types of end restrainers for the casing member have been examined experimentally. The BRB braced frames were tested under the reversed cyclic static loading technique. The hysteretic behavior of BRB braced frame was observed during the tests. As a result of experimental study, the local and global damage was not observed on the BRBs. Furthermore, during the experimental study, the connection between the BRBs and frame member were investigated in detail.