Research On Behaviour Of Concrete-Filled Circular Steel Tubes With Inner Section Steel Under Complicated Loading States

In the past,much research has been done on reinforced concrete(RC),steel reinforce concrete(SRC)and concrete-filled steel tube(CFST)at home and abroad,especially,in the condition of the members under simply loading states.On the contrary,research of the members under complicated loading states was a little.But,with the deepening of research and the need of practical engineering,the CFST with inner section steel has achieved high performance and has been taken seriously,because of combining the advantages of SRC and CFST.In this paper,the research on behaviour of concrete-filled circular steel tubes with inner section steel was carried out by the finite element software ABAQUS.And the main contents are as follows:(1)Based on the reasonable constitutive models of steel and concrete,the element type and boundary conditions,the finite element(FE)models of RC,SRC,CFST and CFST with inner section steel have been established and analyzed.It is shown that the FE method can be used to study the behaviour of the CFST with inner section steel by the good agreements of the numerical computing results and the tested results.(2)The numerical simulation of the CFST with inner section steel under compression,torsion,bending and shear conditions were carried out,in addition,the stress distribution and the bearing capacity conditions were studies,as well as the main influence parameters,such as strength of concrete,strength of steel tubes,strength of section steel,ratios of steel tubes,and ratios of section steel.(3)The numerical simulation of the CFST with inner section steel under combined loading conditions was studies,as well as load versus deformation curves and load distribution conditions.Finally,the influences of loading paths on the members were researched.