Load-carrying Capacity Analysis Of Concrete Filled Double Skin Steel Tubular Column With SHS Outer And CHS Inner Section Under Axial Compression Combined With Biaxial Bending

This paper mainly study the behavior of concrete filled double-skin steel tubular (CFDST) beam-columns, which outer tube is square hollow sections(SHS) and inner tube is circular hollow sections(CHS). The research work is summarized as follows:1. ReviewThe research on CFDST is reviewed firstly. To list the current research on CFDST home and abroad. To pointed out the insufficiencies of researching CFDST mechanical properties in the field of study. The objectives of the present word and content are described.2. The research on CFDST with SHS outer and CHS inner section under biaxial bending moment. Considering the influences of slenderness ratio, loading eccentricity, loading angle and other parameters. Six tests under biaxial bending moments were carried out. The manufacturing process and test program are introduced. The details of the tests are described, and the phenomena are analyzed.3. Numerical analysis of the load versus deformation relationship of CFDST with SHS outer and CHS inner. Based on the stress-strain relationship of steel and concrete, numerical method is used to analyze the load versus deformation relations of CFDST with SHS outer and CHS inner. Good agreements are obtained compared with test results. Based on the ABAQUS, this article showed a penetrating analysis on the working principle of CFDST under biaxial bending moment.4. Simplified models of bearing capacities of CFDST with SHS outer and CHS inner.The effects of load eccentricity, slenderness ratio, yield strength, concrete strength and loading angle on M-N interaction curves are analyzed. Based on the parametric analysis, simplified models are derived to predict the load-carrying capacities of the composite members. The predicted results are in good agreement with those of tests.