Seismic Analysis Of The Square Concrete-filled Steel Tubular Column With End Longitudinal Stiffener

Under seismic action, the square concrete-filled steel tubular column is esasy to local buckling in the end, and after the local buckling of steel tube, the confinement effect to concrete decreased, the concrete of compressive side w as crushed earlier, the bearing capacity of the column began to decrease significantly and ductility decreased. In order to improve the seismic behavior of square concrete-filled steel tubular column, the end strengthened square concrete-filled steel tubular column was put forward in this paper, and refined finite element analysis was conducted to end strengthened square concrete-filled steel tubular column with longitudinal stiffener by using finite element analysis software MSC.Marc, push-over analysis was conducted by using SAP2000, and preliminary discussed the seismic behavior of the end strengthened square concrete-filled steel tubular column frame structure. The main research work of this thesis could be summarized as follows:(1)Put forward new ways to strengthen the end of square concrete-filled steel tubular column, and refined finite element analysis was conducted to square concrete-filled steel tubular column with end longitudinal stiffener on the basis of verified the rationality of the finite element model, getting the setting method of end ribs.(2)Refined finite element models of the square concrete-filled steel tubular column with and without end longitudinal stiffener were analyzed under different parameter conditions including the strength of concrete 、strength of steel、steel ratio、axial compression ratio and height-width ratio. Put forward calculate formulas of the bearing capacity and ductility increase coefficient to square concrete-filled steel tubular column with end longitudinal stiffener.(3)The analysis models of end strengthed and ordinary square concrete-filled steel tubular column frame structure with 2 different heights(5 floors, 15 floors) were established using the structure analysis software SAP2000, wher e the bearing capacity and ductility increase coefficient were used. Through the push-over analysis, discussed the seismic behavior of end strengthed and ordinary square concrete-filled steel tubular column frame structure and provided references for the a seismatic design and application of end strengthed square concrete-filled steel tubular column.