| Among the existing super high-rise structural systems,the frame-core tube structure is one of the system types most favored by architectural architects.However,with the continuous breakthrough of structural height,the large horizontal displacement in these traditional framecore tube buildings has aroused people’s attention to structural design,which has led to a higher demand for structural design.The subsequent frame-core tube equivalent calculation models have also emerged in endlessly.The most representative ones are the generalized bending-shear coupling model and the rocking model.The generalized bending-shear coupling model is considered comprehensive,but there are many restrictions.The calculation is cumbersome,and the swing model only considers the main components,and the design is simple.The lateral shift spectrum,as an analysis method biased to analyze the seismic response of structures,has statistical laws and has attracted more and more attention from structural designers.Based on the advantages and research status of the current generalized bending-shear coupling model,this paper firstly completes the estimation of the overall lateral stiffness based on the combination of the improved bending-shear coupling model and the side shift spectrum,and then proposes a bridge based on the period ratio The demand index-base overturning moment ratio is used to estimate the overall lateral stiffness and the design method of sub-system stiffness distribution.Based on the above analysis of the above situation,this article has done the following work:(1)The overall lateral stiffness is estimated based on the improved bending-shear coupling model.Based on the improved generalized bending-shear coupling model,the time scale analysis is carried out under the conditions of 30 near-field waves and 30 far-field waves selected by MATLAB programming,and the inhomogeneity coefficients of the number of modes and layer quality are studied and discussed.And the lateral stiffness ratio(the ratio of structural shear and bending deformation)to the influence of the lateral shift spectrum,the reasonable values of these influence parameters are obtained,and the overall lateral stiffness of the structure is estimated,that is,the period ratio is calculated.(2)The relationship between the section stiffness and section thickness of the core tube is deduced.Through the establishment of the relational expression,it can be obtained that:when the core tube shrinks in one direction,the section moment of inertia and section area are linearly related to the section thickness change function;when the core tube changes in two directions,the section moment of inertia and section thickness change function show a cubic function change.,While the cross-sectional area and the cross-sectional thickness change function still presents a linear relationship.(3)Deduction and verification of the anti-rotation matrix and the analytical solution of the non-uniform Euler beam with two strengthening layers and the rocking model are carried out.The characteristic parameters of the free vibration of Euler beam and the rocking model calculated by the MATLAB program,which are divided into linear stiffness and nonlinear stiffness change,and the first three modes of vibration are highly consistent with the calculation results of the corresponding finite element model established by D-SAP.(4)Realize the stiffness distribution based on the period ratio from the overall stiffness to the sub-system.Under the circumstance that the period ratio of the total system and the sub-system remains unchanged,starting from the required index-base overturning moment ratio,a series of stiffness distribution schemes in the sub-systems with linear stiffness change and non-linear stiffness change are obtained. |
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