| Mega-sub controlled structure system is a kind of structure system which takes advantage of substructure as tuned mass damper(TMD)in the mega structure.Its structure form is novel and has the characteristics of secondary force transmission.It is one of the major issues in the field of architectural engineering.However,the current research on mega-sub controlled structure mainly focuses on the mega frame structure,and the structure height is relatively low.In order to realize the seismic control of super high-rise mega structures,this paper applies the mega-sub controlled structure system to the super high-rise mega frame-core tube structure.Through theoretical analysis and simulation,the damping mechanism of a single independent subframe in a super high-rise megasub frame-core tube structure and the influence of related parameters on the damping effect of the whole structure are studied.Combined with the practical engineering cases of super high-rise buildings in China,the tuning damping mechanism of multi-damping subframes and multi-isolation subframes in super high-rise mega-sub frame-core tube structure is analyzed,and the damping performance of the whole structure is optimized from the perspective of the frequency ratio of the independent subframes.The main research contents and achievements of this paper are as follows:(1)The idea of applying the independent subframe to the super high-rise mega frame-core tube structure for tuned shock absorption is proposed.Combined with the research results of mega-sub controlled structure system,the super high-rise mega-sub frame-core tube structure and the traditional mass tuned vibration damping structure system are compared and analyzed.A simplified plane linear elastic model is used to analyze the dynamic response of a super high-rise mega frame-core tube structure with a single independent subframe.The motion equations of the main structure and the independent subframe under earthquake action are established,and the transfer function and amplitude response function of the whole structure in the regular coordinate system are derived.The main parameters that affect the damping performance of the mega-sub frame-core tube structure are studied and analyzed.Combined with the influence law of each parameter on the damping effect of the structure,several suggestions for the design of the super high-rise mega-sub frame-core tube structure are put forward.The results show that a single independent subframe can play a excellent tuned damping effect in the super high-rise mega frame-core tube structure,and the damping effect of the mega-sub frame-core tube structure can be significantly improved by reasonably adjusting the location,mass ratio,frequency ratio and damping ratio of the independent subframe.(2)Taking Tianjin Gaoyin 117 building as the background engineering case,the 3D finite element model of the original super high-rise mega frame-core tube structure and the mega-sub frame-core tube structure with multiple shock absorption subframes are constructed by PKPM software,and the structural modal analysis is carried out by Satwe program.According to the current code,the corresponding seismic waves are selected for dynamic time history analysis.By analyzing the overall floor index and time-history response of the structure,the damping mechanism and performance of the super high-rise mega-sub frame-core tube structure under the action of multiple subframes are studied.Taking floor displacement and floor shear as damping performance indexes,the damping coefficient of the structure is set,and the frequency ratio parameters of the damping subframe in the mega-sub frame-core tube structure are optimized and analyzed.The results show that the seismic response of the main structure can be significantly reduced by setting multiple damping subframes in the super high-rise mega frame-core tube structure.The damping effect of subframes in each section can be optimized by adopting the interval frequency ratio,and the damping performance of the whole structure can be significantly improved by reducing the average frequency ratio of subframes in the mega-sub frame-core tube structure.(3)The dynamic time history analysis of the 3D finite element model of the original mega framecore tube structure and the mega-sub frame-core tube structure with multiple isolation subframes is carried out by SSG nonlinear software.The damping mechanism of the mega-sub frame-core tube structure with multiple isolation subframes is studied from the perspective of overall index and energy,and the frequency ratio parameters of the isolation subframes are optimized.The damping performance of the mega-sub frame-core tube structure with multiple damping subframes and with multiple isolation subframes are compared from the aspects of overall damping effect,energy dissipation and comprehensive application.The results show that the multiple isolation subframes can not only produce a good tuned damping effect in the mega-sub frame-core tube structure,but also participate in the energy dissipation of the structure,and its tuned damping effect is better than that of the damping subframe.Moreover,the seismic isolation layer bears most of the deformation and internal force,so that the comfort level of the upper subframe can be improved under the earthquake action.The results of this paper show that the super high-rise mega-sub frame-core tube structure has excellent structural damping performance,and both the damping subframe and isolation subframe can play a good tuning damping role in the mega frame-core tube structure.Through the study of such structure form,the means of damping control of super high-rise mega structure are enriched,and the application of damping isolation subframe TMD in super high-rise mega structure is provided. |
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