Analysis Of Shear Lag And Plastic Energy Dissipation Of Frame Tube Structures Under Seismic Action

Firstly,this paper makes theoretical analysis and studies the influence of the distribution law of bending stiffness on high-rise frame-tube structures by using the curvature differential equation.Secondly,the shear lag effect is an inherent phenomenon of the frame-tube structure,which weakens the spatial effect of the structure and reduces the bearing capacity of the structure.In this paper,the factors affecting the shear lag effect(floor)are analyzed from a new perspective,and a conclusion is drawn by comparing multiple groups of models.Finally,the structure will be damaged under the action of rare earthquake.In this paper,the related indexes of structural plastic energy dissipation and damage are analyzed by means of numerical simulation.The main research contents are as follows:By introducing the plane bending stiffness with shear lag and combining the differential equations of bending moment and curvature,the changing law of continuous lateral stiffness is analyzed,and the influence of the changing law of bending stiffness along the height on the lateral deformation of the structure in the elastic state is discussed.Previous literatures mainly focused on the analysis of shear lag effect of frame-tube structure at the component level,without considering the coordination of each component quantitatively,and there were few qualitative studies on the role of floor slab.The effect of floor slab is similar to that of mantang-hall foundation on uneven settlement of foundation.Under the same condition,the edge warping of floor slab with different thickness is different,and theoretical analysis shows that the shear lag effect can be weakened when the floor slab reaches a certain thickness.In this paper,the influence of different plate thickness models on shear lag is analyzed.Finite element analysis was carried out with ABAQUS,and the constitutive models and element types of concrete and steel bars were introduced in detail.Seismic waves were selected according to the requirements of codes.Based on the characteristics of seismic waves,the plastic energy dissipation and the damage law of connecting beams under the action of rare earthquakes are analyzed.The relationship between the three parameters,namely PGA,Al index and strong earthquake duration,and the structural damage are analyzed by combining the standard method.The significance of this study lies in the systematic analysis of the factors that affect the structural performance and the analysis of the elastic-plastic performance of the structure under the action of rare earthquakes from both internal and external factors.Internal cause:the stiffness distribution of the structure itself should be gradually reduced from bottom to top according to the rule of cubic curve,and the uneven warping of the floor can be reduced by increasing the thickness of the floor,so as to reduce the shear lag effect.External cause:the greater the peak acceleration of seismic wave is,the greater the energy input to the structure will be,and the greater the damage to the structure will be.The shorter the effective duration of seismic wave with the same peak acceleration is,the greater the instantaneous input energy will be,which is unfavorable to the structure,which also leads to the dispersion of time history analysis results.