Static Behaviors Of Special-shaped Concrete Filled Steel Tuber Columns

In order to research the axial mechanical behavior of T-shaped concrete filled steel tuber columns(CFST), experimental research and theoretical study are conducted in this paper. And the seismic behavior of special-shaped column frame is also researched based on the axial load experiment. The research work consists of the following three parts:(1) Experimental research on the axial mechanical behavior of T-shaped CFST columns with tensile bar stiffener and steel plate stiffener has been performed. The two kinds stiffeners are put forward to restrain the local buckling of steel tubes and prepared for its engineering application in structures. The experiment includes stiffened T-shaped CFST specimens and T-shaped CFST specimens, and the effect of mechanical behavior and the local buckling of steel tube by stiffeners is mainly researched. The difference of the effect of axial behavior of specimens by two kinds of stiffeners is studied too. The result of the experiment shows that tensile bar stiffener and steel plate stiffener can postpone or avoid the local buckling of steel tube and increase the bearing capacity and ductility of the specimens.(2) The ABAQUS was used to the theoretical analysis based on the experiment research. The finite element model was established by the section size and strength of materials of test specimens. Stress-strain bilinearity relationship was adopted for the constitutive model of steel tube and the plastic damage model was adopted for the constitutive model of concrete, the stress-strain relationship of plastic damage model used that of Code for Design of Concrete Structures. The simulation result agreed well with the test result. The calculation method of bearing capacity of stiffened T-shaped CFST columns was put forward compared with the bearing capacity calculated by many countries' code.(3) The special-shaped frame model was established by PKPM based on the experiment and simulation result. Under the condition that the axial compression ratio and the largest story drift angle are both less than the code limit values, the structure height is increased orderly meanwhile the economic benefits of special-shaped CFST column frame structure and the special-shaped reinforced concrete column frame structure are compared. The Pushover analysis was carried on about special-shaped CFST columns frame and then seicmic performance under different seismic fortification intensities of special-shaped CFST columns frame was researched.