Study On Hysteretic Behavior Of Concrete Filled Double Skin Steel Tubular Members After Exposed To Fire

The concrete filled steel tube has a series of advantages and has been recognized and widely used in Engineering.Compared with the concrete filled steel tube,CFDST has not only a little bit,but also the bending stiffness is bigger,the weight is smaller,and the possibility of structural damage in the earthquake is smaller.However,when the component is subjected to fire,the mechanical properties of the material will be changed,which may affect the seismic performance of the component.This particular research at home and abroad is rarely reported abort fire,so the study on hysteretic behavior of CFDST after fire for the future development of composite structure in the field of civil engineering is of extraordinary significance.The specific work of this paper is as follows:(1)Tested the CFDST component according to the ISO-834 heating curves,then tested 18 square and circular components for the hysteretic performance by the experiment with the hollow ratio,the time of the fire,the concrete strength and the axial compression ratio.Analysed of the hysteretic loops,deformation,stiffness and energy dissipation capacity(2)Used ABAQUS to simulate the temperature of the component according to the ISO-834 heating curves.Compared with the experimental results,the heat radiation and other factors are determined,ready to fit with the mechanical field model.(3)The performance of steel and concrete and the constitutive will change after fire.By means of ABAQUS software,the temperature field and mechanical field ware fitted together after selecting the appropriate constitutive.Compared the calculated curves and the experimental,Analysed of the hysteretic loops,deformation,stiffness and energy dissipation capacity and mechanism of the component in the bearing of the reciprocating load.