Study On Concrete-filled Square Steel Tubular Column And L-shaped Column Composed Of Concrete-filled Square Steel Tubes

Concrete-filled square steel tubular column has a better bearing capacity, earthquake resistance, fire resistance, and so on. So, concrete-filled square steel tubular column becomes the direction of multi-story steel-frame structures.For calculation method, the superposition theory, which is of simple calculation, of clear conception, of reliable safe, is verified to be suitable for the calculation of concrete-filled square steel tubular column, because of the supersonic flaw detecting and the theoretical analysis. Three problems, which are distributing coefficients of axial pressure, section turning radius, increase of bearing capacity, are point out, according to analysis for existing formula of superposition theory. Then, this paper introduces a new calculation method of superposition theory.Special-shaped column composed of concrete-filled square steel tubes is a new type of structural member. Flexible section is its distinct characteristic. L-shaped column composed of concrete-filled square steel tubes (LCFT) is an important part of special-shaped column composed of concrete-filled square steel tubes. Indoor area and space can be enlarged, and decoration can be convenient, while special-shaped columns were designed in buildings. So, special-shaped column composed of concrete-filled square steel tubes will be used widely, with country-wide popularization of the steel structural buildings.For LCFT, equivalent slenderness ratios are deduced, which is an important part of calculating in superposition theory. Buckling coefficient of steel tubes is defined according to existing data of axially compressed experiments for concrete-filled square steel tubular column.For LCFT, short column specimen and long column specimen are designed for axially compressed experiment in order to analysis load bearing capacity of strength failure, and of buckling failure.Before axially compressed experiments are carried on, short specimen and long specimen are simulated by general finite element programming, ANSYS. Results of ANSYS, superposition theory, and axially compressed experiments are concordant so that the feasibility of superposition theory for calculating LCFT isverified. At last, the author puts forward several problems for Concrete-filled square steel...