Assessing the Nonlinear Behavior of Novel Steel Octagonal Yielding Dampers Under Lateral Loads

ABSTRACT A new type of yielding damper, “dual octagonal section” (DOS), for use in the self‐centering moment and braced frames, is developed and numerically evaluated. In the new damper, the interconnection of two octagonal sections to each other is done by groove welds. Also, high‐strength bolts connect them to the support plates to facilitate the replacement and removal of workshop welding. After verification with experimental specimens, numerical evaluations have been done through nonlinear finite element modeling with full details. Elastic stiffness, yielding force and displacement, internal forces of bolts, and other theoretical formulas of design are presented. In this evaluation, the behaviors of DOS dampers under monotonic and cyclic loading by nonlinear finite elements have been fully evaluated. The results of the evaluations show that the stable hysteresis curves and high performance in energy dissipation and ductility, along with the its light weight, ease of fabrication and installation, and removal of the workshop welding, make this new type of damper suitable for use in braced frames and connections of self‐centering steel moment frames. Finally, it is recommended that to achieve optimal performance and executive provisions, some parameters and geometrical specifications be limited.