Development and Cyclic Behavior of U-Shaped Steel Dampers with Perforated and Nonparallel Arm Confi gurations

Metallic dampers are sacrifi cial devices (fuses) that dissipate signifi cant energy during earthquakes while protecting other parts of structures from possible damage. In addition to numerous implementation opportunities of other base isolation systems, U-shaped dampers (UD) are one of the widely investigated and used devices in practice especially in Japan. The present study focuses on enhancing seismic performance of these types of dampers by changing their geometric properties. UDs with perforated (i.e. with holes) and/or nonparallel arms are developed for this purpose. For a better comparison, the criterion of equal material volume (or mass) has been utilized. Three dimensional fi nite element models of the new type of UDs are formed and investigated numerically under selected displacement histories. Based on the obtained hysteretic curves; dissipated energy intensities, eff ective stiff ness ratios, reaction forces, eff ective damping ratios are evaluated in this parametric study. It is found that both damper types have merits in use of seismic applications and that the selection of the damper confi guration is dependent on the design specifi c issues. KCI Citation Count: 2