Internal Force And Displacement Calculation Of Frame-Shear Wall Structure With Vertical Segmented Variable Stiffness And Its Application

Frame-shear wall structure system is widely used in high-rise buildings.The different cross-section and geometrical arrangement of the frame and shear wall in each floor of the structure will lead to the structural stiffness and stiffness ratio to change along the height,which will change the displacement and internal force of the frameshear wall structure.It is of great significance to explore the reasonable structural stiffness distribution rules in order to control the deformation index and internal force concentration more effectively in frame-shear wall structural design.Based on the equivalent continuum model of frame-shear structure,a new method for quickly estimating the displacement and internal force of the segmented variable stiffness frame-shear structure is proposed by combining the continuation method with the finite element method.On this basis,the influence of frame stiffness and shear wall stiffness change along the fa?ade on the structural response is discussed in detail by means of parametric analysis.Finally,the design optimization suggestions for the stiffness arrangement of the frame-shear wall structure are given.The main work and research results of this paper are as follows:(1)The continuous model is used to analyze the vertical segmentation variable stiffness frame-shear structure and the differential equation of displacement for the continuum is established.By using the differential equation of displacement control and the continuity condition between the segments,the recursive relationship of the segmentation solutions is derived,and then the boundary condition is introduced to obtain the analytical expression of internal force and displacement.The recursive method simplifies the solution of differential equation of piecewise variable stiffness structure,therefore the continuous method is applied to the frame-shear structure with vertical segmentation variable stiffness.The correctness of this method is verified from both qualitative and quantitative perspectives through examples.(2)Extracting the data in the finite element calculation process,obtaining the element stiffness matrix of each component.And then through the steps of rigid floor transformation,assembly of the overall stiffness matrix and static cohesion,considering the stiffness center,the equivalent stiffnes,submatrix is obtained finally from which two basic parameters of the continuous calculation called equivalent shear stiffness and equivalent bending stiffness are extracted.(3)Studying the influence of bending stiffness and shear stiffness change rate of the upper,middle and lower positions on the structural response of the frame-wall structure with variable stiffness,the following conclusions are obtained: a)As the stiffness decreases,the apex lateral displacement and the maximum drift increase,and the change of the bottom bending stiffness and the change of the top shear stiffness have a great influence on it.If the height of the upper stiffness weakening zone is small,the lateral displacement of the structure cannot be quickly changed by changing the shear stiffness.b)A decrease in lower bending stiffness will cause the position of the maximum drift to fall and a decrease in upper shear stiffness will cause the position of the maximum drift to rise.c)When the shear stiffness changes,a large shear force mutation will occur at the changing floor and the larger the stiffness change,the larger the abrupt value.d)The upper shear stiffness has a greater influence on the force of the floor and the segmentation change of the shear stiffness will cause the position of the maximum horizontal force floor to transfer.e)The height of stiffness strengthening zone of bottom shear wall need not be too large.