Study on A Novel Sacrificial-Energy Dissipation Outrigger

Abstract

The frame-core tube-outrigger structural system is widely used in tall buildings, in which outriggers coordinate the deformation between the core tube and the moment frame, leading to a larger structural lateral stiffness. Existing studies indicate that outriggers can be designed as a fuse of tall buildings through dissipating seismic energy after yielding, to protect the main structure. Under the action of the maximum considered earthquake (MCE), it is found that the hardening effect of BRB outriggers will increase the percentage of the inelastic energy dissipation of the other structural components. Meanwhile, due to the local buckling-induced severe deterioration and damage of conventional outriggers, conventional outriggers are difficult to repair after an earthquake. To overcome these problems, this study proposes a novel sacrificial-energy dissipation outrigger (SEDO) to improve the seismic resilience of tall buildings. The inclined braces of this novel SEDO are composed of a sacrificial part and an energy dissipation part. Therefore, it remains elastic under the design-based earthquake (DBE) and dissipates inelastic energy under the MCE. Moreover, the detailing of this novel SEDO are proposed based on experimental studies. The optimum strength ratio between the sacrificial part and the energy dissipation part is determined as 6:4 based on nonlinear time-history analyses (THAs). Afterwards, SEDOs are used in a tall building to verify its seismic performance through nonlinear THAs. Consequently, this study indicates that the novel SEDO is able to protect the other structural components and effectively improve the seismic resilience of tall buildings.