Seismic Behavior Analysis Of Steel-Reinforced Concrete Composite Torsion Members Under Confined Concrete Stress-strain Model

The steel reinforced concrete structure is a kind of combination mechanism which has developed rapidly in recent years.It combines the two materials,steel and concrete,and works together to provide better seismic performance for components and structural systems.However,in the event of earthquakes,the components are often in a complex state of force,which component of the seismic performance of a higher demand.With the progress of the research,the effect of the twisting effect on the components began to be the focus of attention by the researchers.Various post-earthquake investigations also show that torsional effects often occur in earthquakes,and even the main cause of building damage.In this paper,the seismic performance of steel reinforced concrete members under composite torsion is studied,and the following work is carried out:(1)Based on the analysis of the influencing factors and the torsion theory of the seismic performance of the reinforced concrete members,the material constitutive model consider the constraint effect of steel bones and stirrups on concrete,which is creatively used to construct the material properties of the concrete.Based on the curves in the specification,the concrete is divided into three parts: unconstrained concrete,stirrup-confined concrete and steel-reinforced concrete.The stress-strain curves are constructed respectively.Finally,a constitutive model is proposed to simulate the seismic performance of SRC members.This makes full consideration of the steel bones and stirrups on the concrete constraints to improve the performance of the components,so that the simulation of the hysteresis curve changes in the stage more clearly.(2)The analysis of this paper is based on the use of finite element software ABAQUS to simulate the performance of components.The design of the bottom pillar in the frame structure is taken as the design prototype of the component.The components are subjected to the seismic action by modeling the components,assigning the material properties,assembling and setting the contact parameters,setting the analysis step,load and boundary conditions,and running the work.(3)In this paper,the axial pressure coefficient,the torque,the amount of steel and two directions under the loading of steel bone size changes as the influencing factors.The effects of different factors on the seismic performance are analyzed from the aspects of hysteresis curve and skeleton curve variation,energy consumption capacity change,stiffness degradation speed,ductility size and so on.Finally,the rules found in the analysis process are summarized,which can provide the basis for future seismic design.