Seismic Performance Analysis Of Frame-double Steel Plate Composite Wall Core Tube Structure With Energy-dissipating BRB Outrigger Trusses

In recent years,a large number of super high-rise buildings have been built in China,and their seismic performance has become a research hotspot in engineering academia.In order to improve the ductility and energy dissipation capacity of super high-rise buildings,and intend to build resilient structures that could be easy to repair after an earthquake,this paper creatively combines energy-dissipation BRB and double skin composite wall applied to the tall building and proposes a frame-double skin composite wall core tube structure with energy-dissipation BRB outriggers which will establish the earthquake recovery function structure.YJK and ABAQUS software are used to conduct a series of studies on the seismic performance of this structural system,including the mechanical properties,deformation capacity,energy dissipation performance and plastic development law of the structures under the action of earthquakes.The main work and research results are as follows:(1)The frame-double skin composite wall core tube structure of super high-rise under seismic loading with magnitude 8 is designed and the outrigger webs between the frame and the core tube are designed by ordinary braces and energy-dissipation BRB respectively.The seismic performance of these two structures is compared and analyzed.The results show that even if the double skin wall with good ductility is used,the BRB outriggers still play a good energy dissipation effect,reduce the damage of core tube walls and coupling beams,and optimate the plastic energy dissipation distribution of the structure.(2)The structural models are established respectively in several ways that are corresponded to the mega frame,weaken the stiffness in the core tube and replace the walls at different positions on the upper part with steel frame-ordinary steel bracing or buckling restrained bracing at different heights.And Reaction spectrum analysis,time history analysis and static elastoplastic analysis are carried out to study the influence of these conditions on structural performance.The results show that the use of the mega frame greatly reduces the steel consumption of the frame but increases the structural stiffness mutation.Weakening the core tube stiffness will increase the damage to the core tube concrete in the middle and upper strengthened stories while improving the usable space of the building.Replacing the steel frame-braced system for the upper part of the core tube has little effect on the seismic performance,which is beneficial to reduce the project cost.(3)Under a real super high-rise building,a double core tube structure with BRB outriggers was designed using a performance-based seismic design method.The seismic performance analysis results show that this structure is reasonable in design,has strong load-bearing and anti-lateral ability,meets the established seismic performance objectives,and can form multiple seismic fortification lines.The coupling beams between the two core tubes have great stress and early yield,which will lead to the asynchronism of the damage to the two cores under the earthquake action.