Comparative Study On The Effect Of Wing Wall On Seismic Reinforcement Of Bottom Frame Structure

The bottom frame structure generally refers to the bottom is a frame structure or a frameshear wall structure,The upper part is a mixed load-bearing house in the form of a framemasonry structure.Because the bottom frame structure is a mixed structural system composed of two different lateral force resistant systems,the bottom layer and the transition layer have low stiffness and form a weak layer.In the earthquake,serious damage often occurs,causing greater casualties and economic losses.Therefore,it is very necessary and important to study the seismic mechanism of the bottom frame structure and propose appropriate reinforcement measures.In this paper,based on the finite element numerical analysis software,the non-linear pushover method is used to study the bottom frame structure.Taking a typical bottom frame building as a model,first analyze the seismic weakness of the bottom frame structure and its seismic performance under different earthquake levels.Then study the changes in the seismic mechanism of the structure and the improvement of the seismic performance after adding the wing wall to explore the rationality and design points of the wing wall reinforcement of the bottom frame structure.The research content and results of this paper include the following points:(1)The common bottom frame structure is simulated in SAP2000 finite element analysis software,and the modal analysis and static elastic analysis of the bottom frame structure are carried out.It is found that the X and Y axis translation of the bottom frame structure in this paper is the dominant vibration direction;The stiffness of the Y-axis direction is weaker than that of the X-axis,which is the weak direction of the structure;the displacement of the bottom layer of the structure is much larger than the displacement of the other layers,which is the weak layer,showing obvious characteristics of "upper rigidity and lower flexibility";(2)Through the modal analysis and static elastic analysis of the bottom frame structure,it is found that the translation of the bottom frame structure in this paper is the dominant vibration direction along the X and Y axis translation,The stiffness of the structure in the Y-axis direction is weaker than that of the X-axis,which is the weak direction of the structure.The bottom vibration of the structure is relatively strong,and it is a weak layer,showing obvious "upper rigidity" characteristics;(3)Through the static nonlinear analysis of the bottom frame structure under 7,8,and 9 degrees of earthquake in the Y direction It is found that the displacement of the bottom layer of the structure is large,the plastic deformation is concentrated at the bottom,the shear force and bending moment of the frame column are larger than the upper structure,the rigidity of the bottom layer is obviously insufficient,and it is prone to serious damage,which is the weak layer of the structure;(4)By strengthening the wing wall of the bottom frame structure and performing static nonlinear analysis,It was found that after the reinforcement,the displacement of the structure was reduced,the shear force between the layers was increased,the shear force of the frame column was reduced,the destruction of the structure was delayed,the rigidity and bearing capacity were improved to a certain extent;(5)By changing the thickness and length of the wing wall,it was found that increasing the length of the wing wall significantly improved the seismic performance of the structure.(5)By changing the thickness and length of the wing wall,it is found that increasing the length of the wing wall significantly improves the seismic performance of the structure,especially under the 8-degree and 9-degree earthquakes,the structural member damage is reduced,and its lifting effect is better.Increasing the thickness of the wing wall can also enhance the lateral rigidity of the structure,however,the improvement of the seismic performance of the structure is not high;...