Performance-based plastic design and seismic performance evaluation of twisted diagrids with shear links

Twisted diagrid tube structures have become popular due to their significant lateral resistance and esthetic potential. However, the ductility and energy dissipation capacity of twisted diagrid structures are poor. This paper presents a seismic resilient fused structural system named the twisted diagrids with shear links (TDSL), and the performance-based plastic design (PBPD) method is introduced for designing a 24-story prototype structure. The numerical model of the TDSL prototype is established, then nonlinear static and dynamic analyses are conducted to evaluate the seismic behavior of the prototype. The results reveal that the TDSL system can significantly improve the post-yield performance compared to the conventional twisted diagrid structure, and the performance objectives are achieved properly. Subsequently, incremental dynamic analyses are carried out to investigate the collapse fragility of the TDSL prototype, and the collapse risk of the prototype is assessed by FEMA P695. The results indicate that the TDSL prototype has satisfactory collapse-resisting capacity under earthquakes. It is also found that corner columns can improve the seismic safety of the prototype against collapse. In general, the TDSL system is an appealing choice for twisted buildings in seismic regions.