Seismic Assessment of Suspended-Zipper Braced Frame (SZBF) in Coastal Steel Structures Equipped with ADAS-SMA Hybrid Damper

In this paper, a suspended-zipper braced frame (SZBF) equipped with hybrid damper consisting of Added Damping and Stiffness (ADAS) metallic damper and shape memory alloy (SMA) wires is introduced. The proposed seismic-force-resisting system is designed by performance-based plastic design (PBPD) method, which in addition to a significant reduction in the residual displacement of the structure, can increase the collapse displacement amount by providing a suitable lateral strength and ductility compared to the conventional SZBF. A new method for designing the proposed hybrid damper is presented, in which a factor of highest hysteretic energy is provided. The existing models in this paper are two high-rise ۱۲ and ۱۶-story SZBFs in two cases (a) with the conventional system and designed by force-based design method (b) with proposed hybrid damper and designed by the PBPD method. Seismic assessment of the proposed SZBF (PSZBF) by nonlinear static analysis is performed under two lateral load patterns of parabolic and uniform, in accordance with the FEMA-P۶۹۵ in OpenSees software. Using the PBPD design method instead of the FBD method reduces the steel consumption by approximately ۵.۵-۷.۳% in the SZBF, which is expected to decrease further with the increasing number of stories. Since the PBPD method results in a weaker design of columns and braces than the FBD method by about ۵-۱۰%, the elastic stiffness of the PSZBF models is about ۵% lower than the FBD models, that the elastic stiffness in both models can be assumed to be equal. Although PSZBF models have lower maximum lateral resistance than FBD models, they are able to absorb energy about ۲۵% more in addition to increasing collapse lateral displacement.

کلیدواژه ها:

Suspended-zipper braced frames ، SMA material ، ADAS Damper ، Nonlinear static analysis ، OpenSees