Design and testing of a self-centering friction damper-brace for compression ultimate limit state: Inelastic buckling

This paper investigates the design procedures and experimental testing of a low -damage brace equipped selfcentering friction -based connection named Resilient Slip friction Joint (RSFJ). The brace energy dissipation and restoring force is provided by the damper component. Previous studies have shown that the damper ultimate compression strength might be jeopardized due to damper rotational flexibility, which might lead to premature elastic buckling of the brace. To address the issue, a concept of telescopic tubes was introduced to be put in parallel to the damper(s). The design of the telescopic tube requires a thorough framework that considers different possible failure loads and the collapse modes, so that the brace ultimate strength can be accurately estimated. Such a process tends to be more complex than the conventional Concentrically Braced Frames (CBFs), due to the non-continuity(ies) appearing as damper installation which may lead to possible plastic hinge formation in different locations of the brace. This study aims to employ second -order plastic analysis for the design of the damper -brace assembly. The proposed method is, is then validated with current international codes ' procedure and also with destructive tests on the self -centring brace specimens. Finally, the seismic design considerations including the design of the connections and protected members are discussed in this paper. The current procedure could also be recruited for other new emerging damper -braces as well.