Research On Mechanical Properties Of Slender L-Shaped Column Composed Of Concrete-filled Steel Tubes Connected By Steel Linking Plates

Due to the limited land resources as well as rising house prices,people's living demands keep increasing in recent years.As a novel kind of column,Special-shaped column composed of concrete-filled steel tubes connected by steel linking plates(SCFST columns)can not only be embedded in the walls which solves the problem of extending outside the walls caused by traditional columns but also utilize the advantages of concrete-filled steel tubular columns,so SCFST columns have a bright application prospect.In order to save steel and concrete consumption,L-shaped column composed of concrete-filled steel tubes connected by steel linking plates(LCFST columns)are mostly used in the engineering projects.As to LCFST columns,on the basis of previous research outcomes,LCFST columns with different configurations are discussed first in this paper and then experimental as well as numerical investigation of LCFST columns considering the parameters of slenderness ratios,thickness or width of the steel linking plates and eccentricities are presented.Finally,formulas that predict the load carrying capacities of LCFST columns under axial or eccentric loading are put forward based on the modification of the technical specifications.(1)Experimental and numerical investigation of LCFST columns with different slenderness ratios under axial loading is conducted.It is found that linear stiffness as well as load carrying capacities of LCFST columns decrease with the increase of slenderness ratios which is consistent with the anticipated trend.For specimens with small slenderness ratio,local buckling was observed on symmetrical locations,while for those with large slenderness ratios,the failure mode was global buckling.It can be judged from the failure modes of the specimens that as the connectors,steel linking plates and the transverse stiffeners were strong enough to make each mono column work together.(2)Experimental and numerical analysis of LCFST columns with different thicknesses in steel linking plates under axial loading is conducted.It is found that linear stiffness as well as load carrying capacities of LCFST columns go up with the increase of the thicknesses of steel linking plates.In addition,out-of-plane deflections of each mono columns are smaller for the specimens with larger thicknesses in steel linking plates which means increasing steel linking pates' thicknesses contributes to its higher confinement on the mono columns.(3)Experimental and numerical analysis of LCFST columns with different widths in steel linking plates under axial loading is conducted.It is found that load carrying capacities of LCFST columns rise by increasing the widths of the steel linking plates indicating that part of the loads are undertaken by the steel linking plates.However,integrity of LCFST columns becomes weak with widths of the steel linking plates increased which can be judged by the fact that failure of specimens with larger widths in steel linking plates is caused by the instability of one mono column.(4)Experimental and numerical analysis of LCFST columns with different eccentricities is conducted.It is found that different from eccentric angles which have little influence on the load carrying capacity of LCFST columns,LCFST columns with larger eccentricities have much smaller linear stiffness as well as load carrying capacities and much larger deformation.