Experimental And Theoretical Analysis Of Mechanical Behaviour Of Concrete-filled The Gap Between Stainless Steel And Steel Tubular Columns

The concrete filled double skins steel tubular column,a new type of composite structure,is developed on the basis of solid concrete filled steel tubular column.Besides it possesses the advantages of solid concrete filled steel tube column,it also has light weight,cross section and great bending stiffness.Although it has a lot of advantages,the poor corrosion resistance has certain limitation in the application of engineering.Such as the important structures of high resistance to corrosion resistance of bridge pier,platform structure of the sea,and injection pile.Stainless steel has better corrosion resistance,higher temperature resistant,higher strength,better ductility and lower maintenance cost advantages than ordinary carbon steel.So stainless steel instead of common carbon steel can greatly improve mechanical performance.Thus the new type of steel-concrete composite structure was born,it is called concrete-filled stainless steel and steel tubular composite structure in this paper.The mechanical performance of concrete-filled stainless steel and steel tubular columns under axial compression and eccentric loading was studied in this paper by experiment and finite element analysis.(1)Total of 24 speciments were tested on concrete-filled stainless steel and tubular conlumns,including 6 short columns under axial loading condition and18 long columns under eccentric loading condition.The main parameters for short columns are the hollow section ratio,while those for others are the hollow section ratio,slenderness ratio and load eccentricity.The experiment results showed that for columns under axial loading condition,with the increase of the hollow section ratio,the decrease ratio of bearing capacity will become larger.For long columns under eccentric loading condition,with the increase of the hollow section ratio,slenderness ratio and load eccentricity,the stiffness and bearing capacity will decrease obviously.(2)Compared the test of ultimate bearing capacity under axial compression and eccentric loading with stability bearing capacity from modified formulas of the code(DBJ13-51-2003).By comparing the results to verify the rationality of the modified formulas to guide the engineering design of concrete-filled stainless steel and steel tubular composite structure.(3)Establishing finite element models to analysis the mechanic behavior of concrete-filled stainless steel and steel tubular columns under axial loading and eccentric loading.Initial global geometrical imperfection was considered in all models.The calculation results by finite element models are agreed well withexperimental results.(4)Using the finite element models,this paper analyzes the influence of initial global geometrical imperfection,hollow rate,concrete strength,diameter-to-thickness ratio and eccentricity on bearing capacity.