Research On L-shaped Concrete-filled Steel Tube Core Columns Mechanical Properties

With the continuous development of society and the economic level，the requirement ofstructure and layout of the building become higher. Therefore, it requires that the structuralforms and structural components could meet requirements on the space layout and high-rise,long-span of the constructions. Special-shaped steel tube concrete core column is a new type ofstructure. This structure form with the two forms of special-shaped reinforced concrete columnsand concrete-filled steel columns. It can make full use of the space. The enhancement of bearingcapacity and ductility could meet the requirements on high-rise and long-span on the project. Itssteel tube is wrapped up by concrete which can protect the steel and improve the corrosionresistance and fire resistance performance effectively. There are three kinds of them are regularuse: cross-shaped, T-shaped and L-shaped. The wide of these three forms of columns is samewith beams, walls and not exposing beams and columns. It can be used widely in centralcolumns, side columns, and corner columns. In this paper, based on the research group hadspecial-shaped concrete-filled steel tube core columns experimental, by finite element simulationand numerical calculation methods, analyze the properties of strength of L-shaped concrete-filledsteel tube core columns under normal temperature and the ultimate bearing capacity under fire.The major contents are summarized follows:Using the material mechanics of original cross-shaped column of concrete-filled steel tubecore in the test, finite element analyze software ABAQUS is used to analyze the properties ofL-shaped concrete-filled steel tube core columns at different eccentricity, and analyze theinfluence factors of the mechanical properties of the specimens. Meanwhile the specimen failuredeformation, load-displacement curve as well as the components of the load-strain curve areextracted elaborate the various specimens of the failure mechanism and damage characteristics.Analyze the model under uniform fire along the length, by using nonlinear finite elementmethod on the temperature distributions under the action of ISO-834heating curves. Then putthe result of temperature field into mechanical calculation module to calculate. Analyze the fireresistance of L-shaped concrete-filled steel tube core columns in the different axial compressionratio and eccentricities.Numerical calculation by MATLAB program arrives at the ultimate bearing capacity underaxial, one-way, bidirectional different eccentricity of L-shaped concrete-filled steel tube corecolumns. And from a comparative analysis with the finite element simulation of bearing capacity:the results showed that derived using the two methods of specimen bearing capacity of lesserrors and in good agreement, self-compiled program which demonstrates the feasibility andapplicability; On this basis, by changing specimen’s load angle, eccentricity, pipe diameter andpipe thickness, we can analyze bearing capacity of the L-shaped concrete-filled steel tube corecolumns and obtain variation of bearing capacity under different conditions. It can provide areference for the practical application of L-shaped concrete-filled steel tube core columns.