| Connected structure is a kind of complex high-rise building structure.At present,the research on its seismic performance is mainly aimed at the double-tower connected structure with the same or similar story number and stiffness.By changing the stiffness of the tower body,the stiffness of the connected structure,the number of connected structures,the position of connected structures and the connection form,the influence of these factors on the seismic performance is discussed.However,the research on the seismic performance of the twin-tower connected structure with great difference in tower height is rarely involved.In this paper,combined with a project example of double-tower connected frame-core tube structure with great difference in tower height,around the important factor of great difference in tower height,several integral models of PKPM double-tower connected frame-core tube structure are established from the factors of connected layout and connection mode.Through the comparative analysis of the key seismic performance indicators such as the natural vibration period,period ratio,maximum inter-story drift angle,displacement ratio,percentage of overturning moment and base shear,the difference of seismic performance between the double-tower connected structure with great difference in tower height and the double-tower connected structure with equal tower height is explored,and the rationality of the preliminary design model of the structure is evaluated according to the current national design code.In order to further study the seismic performance of the twin-tower connected structure with a great difference in tower height,the nonlinear finite element analysis method based on the three-dimensional solid degradation virtual laminated element theory is used to analyze the lateral performance.By changing the stiffness of the tower body,the VFEAP finite element model is established for different initial shear sharing ratios of the twin towers,and the stiffness degradation and shear redistribution of the structure are obtained.The realization of multiple seismic fortification lines of twin-tower connected structure with great difference in tower height is discussed.In addition,considering the great difference of tower height,the mechanical properties of the connected structure and its connection with the tower are discussed,and the necessary strengthening measures are proposed.Based on the above research,this paper improves the design by adjusting the shear sharing value and taking the necessary strengthening measures,and for this improved design,the finite element model is established by SAUSAGE program under rare earthquake and the dynamic elastic-plastic time-history analysis is carried out to analyze and verify the mechanical performance of the double-tower connected structure under rare earthquake.Through the above research,the conclusions can provide reference for the improvement of seismic design theory of twin-tower connected structure with great difference in tower height. |
