| For super-tall buildings,when subjected to service level earthquakes(SLEs)or design basis earthquakes(DBEs),excessive floor acceleration can lead to damage of non-structural components resulting in severe economic losses.At the same time,“multi-hazards resistance” and “resilience” have become important research frontiers in the international disaster prevention community.However,the existing research about structural multi-hazard resilience design method is still rather limited.For super-tall buildings,there are three key challenges,namely,the floor acceleration control subjected to SLEs or DBEs,the structural resilience subjected to maximal considered earthquakes(MCEs),and the multi-hazards resistance.In this work,a new structural system and its corresponding design method are proposed to solve the above three key problems,and the key components of the new structural system are systematically studied.The main research work of this dissertation is summarized as follows:(1)A new type of multi-hazards resilient steel-concrete composite frame-braced tube-outrigger with vibration reduction substructure(VRS)system is proposed.The main components of the new structure system are introduced.The construction and work mechanism of each component are explained.The performance targets of the key components under different probabilistic earthquake levels and the internal force redistribution of structures under different types of progressive collapse conditions are given.(2)A novel replaceable stiffening angle steel(SAS)component is proposed,which can be used in self-centering frames.Corresponding experiments and numerical simulations are carried out,and the simulation results are in good agreement with the experimental results.The theoretical methods of the initial stiffness and the yield moment provided by the SAS components were proposed and validated by the finite-element(FE)models.(3)Multi-hazards resistant steel-concrete composite frame(MHRSCCF-1)is proposed.Seismic and progressice collapse experimental studies on the substructure of the MHRSCCF-1 and the conventional steel-concrete composite frame are conducted.The FE models corresponding to the tests are established,which can accurately represent the mechanical characteristics of the structure.(4)Multi-hazards resilient steel-concrete composite frame(MHRSCCF-2)is proposed,which can make the structural seismic and progressive collapse damage process stable,orderly,controllable and easy to repair.Seismic and progressice collapse experimental studies on the substructure of the MHRSCCF-2 are conducted.The theoretical models used to calculate the initial stiffness and yield moment of the beam-column connection of MHRSCCF-2 are presented.(5)The concept of VRS controlling floor acceleration of super-tall buildings under SLEs or DBEs is proposed.Based on the flexural-shear coupling beam model,the influence of structural and VRS’s parameters on the floor acceleration reduction effect of super-tall buildings is studied through time history analysis under actual ground motions.The design method of optimal VRS is presented.(6)The design method of multi-hazards resilient steel-concrete composite frame-braced tube-outrigger system with VRS is presented.Based on the FE model of the whole structure,seismic nonlinear time history analysis and progressive collapse analysis are conducted to verify the rationality and effectiveness of the design method of the new structural system. |
