Study of the mechanical properties of axially loaded section steel and steel tube short columns filled with steel-reinforced concrete

A new design model for heavy load-carrying columns ie steel tube column filled with steel-reinforced concrete is established to adapt to the development of high-rise and long-span structures.This kind of steel-concrete composite column is formed by inserting a steel section into a concrete-filled steel tube.An experimental study on the mechanical properties of the composite column is conducted for 12 short composite columns.The effect of concrete strength,the confinement index and the structural steel index on the mechanical properties of the composite column are discussed,and a formula for predicting the ultimate bearing capacity of the composite column is proposed in this paper.Results show that the kind of composite column has high bearing capacity and excellent ductility as concrete and steel work together.So the composite column can effectively improve the collapse resistant capacity of buildings.The results calculated by the proposed formula are also in good agreement with the test results.