Study On Mechanical Properties Of High Strength Concrete Eccentric Column Of Steel Tube Magnesium Deficient Mine

In recent years,concrete filled steel tubular(CFST)has been widely used in practical engineering,but its material is not single,the slip between concrete and steel tubular is prominent,and its mechanical properties are complex.Many scholars at home and abroad have studied CFST extensively.In this paper,a new type of steel tube high-strength concrete short column member with low magnesia ore as core filling material and thin-walled steel tube is proposed.On the basis of previous studies,the mechanical properties of steel tube high strength concrete eccentrically compressed short columns with lean magnesia ores are studied by experimental research,theoretical calculation of fiber model method and numerical simulation of finite element method.The following main research contents are completed:Experiments on steel tube high strength concrete short columns with low magnesia ore are carried out,and the experimental results are obtained.The constraints of the short column are hinged at one end and fixed at the other end.The maximum deflection occurs at L/3 from the hinged support end.The results of load-vertical deflection curves show that when the eccentricity is the same and the eccentricity is 12% higher than that of steel tube high-strength concrete eccentrically compressed short columns,the distribution of longitudinal strain along the section height of steel tube in the two types of short columns basically conforms to the assumption of flat section.The load and failure modes of high strength concrete eccentrically compressed short columns filled with steel tubular lean magnesia ore are calculated by using the fiber model method,and the calculated bearing capacity and failure modes are compared with the experimental results.The results show that:(1)the bearing capacity calculated by the fiber model method is in good agreement with the test results of steel tube high-strength concrete,and slightly errors from the test results of steel tube high-strength concrete with poor magnesia ore;(2)the failure location of the components obtained by theoretical analysis is in agreement with the test results,and the maximum deflection occurs at L/3 from the end of the hinge support.However,the theory of fiber model method does not consider the slip phenomenon between the two,so the influence of the slip phenomenon needs to be further studied.The ABAQUS finite element method is used to further study the short columns of high-strength concrete structure with steel tube and poor magnesia ore.The ABAQUS finite element analysis can better analyze the interface model between steel tube and core concrete.It is mainly through the relationship between steel tube and concrete to know whether the synergistic effect of steel tube and high-strength concrete with poor magnesia ore is better than that of steel tube and high-strength concrete.The results show that when the strength of concrete is the same,the mechanical properties of composite short columns composed of high strength concrete with low magnesia ore and thin-walled steel tube are compared with those of ordinary high strength concrete with steel tube.The main performance is that the compressive strength is stronger,but most of the damaged parts are fracture failure,and the stability performance is slightly worse.