Performance Analysis And Optimization Of Frame-Core Tube Structures With Energy Dissipation Outriggers

With the increasing of high-rise building construction,frame-core tube-outrigger,one of the most important structural system in super-tall buildings,have been widely used.In the frame-core tube-outrigger system,outriggers serve as key lateral force resisting members.The energy dissipating capacities of outriggers are studied in this study,based on which an improved design methods are proposed to improve the energy dissipating capacities of the outriggers.The main research contents include:(1)The finite element models of conventional outriggers and buckling-restrainedbrace(BRB)outriggers are established in Perform-3D.A frame-core tube-outrigger super-tall building is chosen as the prototype building,which is designed through adopting conventional outrigger and BRB outrigger,respectively.For the two different design schemes,their seismic performances are evaluated through nonlinear timehistory analyses at maximum considered earthquake level(MCEs).It is found that the BRB outriggers maintain a high strength during the earthquake,which in return increases the relative ratio of dissipated inelastic energy of other structural components.Consequently,the BRB outriggers dissipate less energy than the conventional outriggers in respective design schemes.(2)Based on the above analyses,a novel sacrificial-energy dissipation(SED)outrigger is proposed to increase the energy dissipating capacity of outriggers.Both experimental tests and numerical simulations on the bolts and web trusses of the SED outrigger are conducted to investigate the seismic performance of such newly proposed outrigger system.The results indicate that the SED outriggers can be achieved in practical applications.The softening response in the hysteretic curves of the SED outrigger is adjustable.In addition,hysteresis loops are also ductile,stable,and repeatable,which indicates a good energy dissipation capacity of the SED outrigger.Further,the finite element models of the proposed SED outrigger are also established to simulate experimental responses with good agreements,which proves the modeling strategies can be used for further studies.(3)Finally,the SED outriggers in the outriggers of both the prototype building and a actual super-tall building.The principle of “equal stiffness and equal strength” is adopted to design SED outriggers.After that,the seismic performance at MCEs of two super-tall buildings with the SED outriggers is compared with that of the respective buildings with the conventional outriggers and the BRB outriggers.The results indicate that the SED outriggers can dissipate more energy than both the conventional outriggers and the BRB outriggers.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 optimize the dissipated inelastic energy distribution and protect other structural components of super-tall buildings under MCEs.