Mechanics Research On Concrete Filled Steel Tube Members With Axial Pressure

Because the structure of concrete-filled steel tubular(CFST)can take advantages of the two kinds of materials adequately,it has many virtues such as high strength,good plasticity and convenience of erection. It caters to the need of the modern structures that is developing for long-span,towering and heavy loaded building.Furthermore,it can resist tough conditions. Especially,with the development of the high-rise building in our country,CFST are researched and implemented comprehensively.However,the section shapes are mostly circular and rectangular.Concrete-filled circular steel tubular has better plasticity and toughness, concrete-filled rectangular steel tubular has many advantages,such as shearing forceresistance and bending force-resistance,so they are widely used in engineering. Usually,thick steel tubes are used in traditional engineering of concrete-filled steel tubes(CFST).Engineering experiences show that using thin-walled steel tubes in CFST engineering can reduce the consumption of steel,the workload of welding and cost of the project.However,when the width(diameter) to thickness ratio of CFST come to a certain value,it is easy for CFST to get a local buckling under axial pressure.Although there are some relevant provisions of the diameter to thickness ratio in the standard of design in our country, its value is a reference to an empty steel column, and regardless tothe support from the core of concrete on the steel, and the results are usually more conservative,so it is necessary for us to have a further research on CFST.In this paper,the CFST under axial compression are studied by using of ABAQUS6.9 with the method of RIKS.The main contents are follows.1,Some questions about ABAQUS simulation are discussed,such as the types of units identified,the constitutive material selected,mesh density, strengthen the convergence of methods,and the methods adopted in this paper are determined.2,Simulate the experiments which have been done, compareing the results of abaqus with the results of experiments to confirm the feasibility for abaqus on local buckling of CFST.3,The specimens mainly include circular and rectangular CFST.It considers the influence of steel strenth,strength of concrete and diameter to thickness ratio on theCFST.4,With large amouts of data through the calculation, determine the range of width(diameter) to thickness ratio of both two sections of CFST.