Located Ribbed Thin-walled Square Steel Tube Concrete Columns Axis Pressure Bearing Performance Finite Element Analysis

The thin-walled concrete-filled steel tubular structure, which has significant advantages such as great bearing capacity, high seismic performance, construction facilitation, has received widespread attention at home and abroad in recent years. But thin-walled concrete-filled steel tube produces local buckling easily, which will reduce the bearing capacity of components and thus affect its overall performance, especially when the cross-section of its components is square or rectangular. Thus besides choosing a proper design method, it is also essential to research on constructive measures which can improve its bearing performance.Based on earlier research results, the working mechanism of the thin-walled concrete-filled square steel tube under axial compression is studied by finite element analysis method in this paper. Main achievements of this research are as follows;1.The existence of stiffeners effectively improves the local buckling performance of the thin-walled square steel tubular and the bearing capacity of the concrete. As for the thin-walled concrete-filled square steel tubular with a larger B/t, its bearing capacity develops apparently as the rigidity of stiffeners grows. Meanwhile, the existence of stiffeners also effectively improves the strength of the core concrete;2.1t is revealed by comparison and analysis that the strengthening effect of the thin-walled concrete-filled square steel tubular (Nua/N0) is proportional to the strength of the steel and the thickness of tubes, and inversely proportional to the strength of the concrete;3.Simplified bearing capacity calculating expressions of thin-walled concrete-filled square steel tubular short columns in regulation of different nations and regions are analyzed and compared. The simplified bearing capacity calculation of thin-walled concrete-filled square steel tubular short columns with stiffeners is discussed, and it is concluded that the experimental result is more compatible to the calculating result according to the slightly revised DBJ13-15-2003(2003) regulation in China.