Optimization Analysis On Frame–Tube Structure To Reinforce Layer Settings Position And Stiffness

In order to overcome the shear-lag effect and solve the problem of the excessive vertex displacement due to the lack of lateral stiffness of the structure,the reinforcing plies are increasingly applied to the design of the high-rise frame-core wall structures.Meanwhile,under the action of the frequently occurred earthquake,the structural weak layer is produced by the sudden change of the structural rigidity and internal force change caused by the greater stiffness of the strengthened layer,which is difficult to show the ductile failure mechanism.The disadvantage of the strengthened layer is not to be ignored.Therefore,this paper is on the premise of reducing the structural lateral displacement and by reducing the anti-seismic adverse effects caused by the sudden change of the internal force as target.In this paper,the deformation,stiffness and internal force of the structure under the seismic action are studied by changing the position and the vertical stiffness of the strengthened layer,to discuss the optimum position and the optimum stiffness of the strengthened stories,hoping to provide some reference for the actual project.In this paper,the calculation model of a practical project in Beijing is established by means of the ETABS finite element software.And the steel truss form is used in the outriggers and girdle structure of the strengthened layer.By changing the location of the single limited stiffness strengthened layer to establish five schemes,and changing the size of the trusses to set two different vertical stiffness of outriggers to set up three kinds of scheme,this article analysis the structural deformation,stiffness and internal force of the frame-tube structure under the seismic loading action,to study on the optimum position of the single limited stiffness strengthened layer and the change rule of the vertical stiffness of two finite stiffness strengthened layer,to make the strengthening layer can effectively reduce the lateral displacement of the structure,and minimize the adverse effects caused by the change of the internal force of the structure near the strengthened layer.Through the research of this paper,the following conclusions are drawn: Under the condition that the total stiffness of the structure remains unchanged,the sudden change of the vertical stiffness and the internal force of the frame-tube structure with the single reinforcement layer is worse than that of the structure with two reinforcing layer;From the point of view of reducing the displacement and reducing the sudden change of the internal force,the optimum position of the strengthened structure of the single limited stiffness strengthened layer is near the height of 0.8H;The mutation amplitude of the axial force and the shear force of the surrounding frame column and the bending moment and shear force of the core tube is distribution along the height,the upper part is small and the lower part is large.