Flexure Based Energy Dissipating Device in Self-Centering Braces

Abstract Self-centering braces, in the current stage of development can accommodate large deformation and force levels. However, there is still a need for improvement of the energy dissipation mechanisms commonly incorporated in these braces. Yield based energy dissipation systems can overcome some of the problems faced with friction-based devices, such as susceptibility to bolt relaxation, long-term creep of friction material and excessive flexing arising in the outer tubes due to friction bolts. However, in these alternative systems multi-wave buckling of the yielding core is present, which is the leading cause of an asymmetric hysteresis of the brace. Hence, in this study, U-shape flexural plates (UFPs) are analyzed as an alternative energy-dissipating device in real scale self-centering braces with a finite element modeling approach. UFP plates yield in flexure and when comparing to direct tension/compression yielding members, they show lower strain demand, resulting in a larger displacement capacity. Implementation of the UFP units in the brace produces a flag shape hysteresis with minimal residual deformation. The proposed system provides some advantages when compared to previous models in terms of increased redundancy, symmetric hysteresis and a more gradual stiffness change.