Research On Mechanical Properties Of Concrete Filled Steel Tubular Laced Columns

Abstract:Concrete filled steel tubular(CFST) laced columns have been widely applied in the field of bridges and buildings. However, current research on the mechanical properties of CFST lattice columns is carried out relatively few.Existing theories about calculating CFST laced columns is compared to steel lattice columns, which neither taking the effects of axial compression and shear deformation fully into consideration, nor reflecting the significant differences between tensile strength and compressive strength, resulting in great difference between calculated and experimental values. there are also some defects in the formulas. Therefore, it is essential to conduct depth theoretical analysis and put out a more accurate formula in theory and practice.The main work and conclusions in this paper are as follows:(1) Refer to the relevant papers, on the basis of superposition theorem, unified theory, and the basic assumptions, deducing equivalent slenderness ratio of concrete filled steel tubular laced columns based on elastic stability theory and exploring the validity and applicability of the relevant formula;(2) According to the principle of virtual work, the formula of equivalent slenderness ratio of CFST laced column with tie plates and cover plates is proposed, and the formula incarnates the effect of tie plates and cover plates on the shearing deformation of concrete filled steel tubular laced column. The calculation example is also given by combining actual projects. The result can be refered by designers to design and reinforce similar columns for mill buildings;(3) Deducing different equivalent slenderness ratio of CFST laced column with distinct oblique lacing bars arrangement, and comparing different mechanical properties of distinct form of CFST laced column. The results show that:the reverse oblique Lacing bar arrangement of CFST laced column could bear higher strength, easy construction, should be given priority in engineering practice; (4) Based on the finite element software ABAQUS, by establishing CFST laced column models, simulated concentrated force levels in the low cyclic on CFST laced columns, and then explore impact of different parameters on CFST laced column skeleton curve, then give design recommendation values finally.