DESIGN AND EXPERIMENTAL STUDY OF A SACRIFICIAL-ENERGY DISSIPATION OUTRIGGER

Outriggers are key lateral force resisting members in super-tall buildings. A frame-core tube-outrigger super-tall building is chosen as the research object. The super-tall building is firstly designed through adopting conventional outriggers and buckling-restrained-brace (BRB) outriggers. Two schemes are derived after the structural design, designated as a conventional outrigger structure (CO) and a BRB outrigger structure (BO). By conducting the nonlinear time-history analyses of the two structures at maximum considered earthquake (MCE) level, it is found that the outriggers in building BO maintain high strength, which in return increases the relative ratio of dissipated inelastic energy in other structural components. Consequently, the BRB outriggers in building BO dissipate less energy than the conventional outriggers in building CO. In this study, a novel sacrificial-energy dissipation (SED) outrigger is proposed to increase the energy dissipating capacity of outriggers. The main design parameters and aseismic performance of the proposed outrigger are analyzed through both experimental studies and numerical simulations. The results indicate that the optimum strength ratio between the sacrificial part and the energy dissipating part of the SED outrigger is about 6:4. Through substituting the outriggers in both building CO and BO with the novel SED outriggers considering the principle of equal stiffness and equal strength, the new SED outrigger structures present more rational energy dissipation modes. The dissipated inelastic energy of outriggers increases significantly while that of the shear walls and other structural components decreases. Therefore, the novel SED outrigger is able to protect other structural components of super-tall buildings under MCEs.