Mathematical modeling and full-scale shaking table tests for multi-curve buckling restrained braces

                                 C. S. Tsai¹, Yungchang Lin², Wenshin Chen² and H. C. Su³

1. Department of Civil Engineering, Feng Chia University, Taichung, Chinese Taipei
2. Graduate Institute of Civil and Hydraulic Engineering, Feng Chia University, Taichung, Chinese Taipei
3. Department of Water Resources Engineering and Conservation, Feng Chia University, Taichung, Chinese Taipei

Abstract: Buckling restrained braces (BRBs) have been widely applied in seismic mitigation since they were introduced
in the 1970s. However, traditional BRBs have several disadvantages caused by using a steel tube to envelope the mortar to
prevent the core plate from buckling, such as: complex interfaces between the materials used, uncertain precision, and time
consumption during the manufacturing processes. In this study, a new device called the multi-curve buckling restrained brace
(MC-BRB) is proposed to overcome these disadvantages. The new device consists of a core plate with multiple neck portions
assembled to form multiple energy dissipation segments, and the enlarged segment, lateral support elements and constraining
elements to prevent the BRB from buckling. The enlarged segment located in the middle of the core plate can be welded to the
lateral support and constraining elements to increase buckling resistance and to prevent them from sliding during earthquakes.
Component tests and a series of shaking table tests on a full-scale steel structure equipped with MC-BRBs were carried out to
investigate the behavior and capability of this new BRB design for seismic mitigation. The experimental results illustrate that
the MC-BRB possesses a stable mechanical behavior under cyclic loadings and provides good protection to structures during
earthquakes. Also, a mathematical model has been developed to simulate the mechanical characteristics of BRBs.

Keywords: buckling restrained brace; energy absorption; passive control; earthquake energy; plasticity model; structural
control; multi-curve BRB
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