Proposal of a New Structural Member Using a Recently Developed High Strength Material

Abstract

The ultra-high strength steel H-SA700 is a relatively new and environment-friendly structural steel with no requirement for intensive heat treatment during manufacturing. In this paper, the cyclic behavior of concrete-filled steel tubes (CFT) using ultra-high strength steel H-SA700 was investigated experimentally. Four column specimens were tested by subjecting them to combined axial and flexural loadings. Two CFT design parameters were investigated: the grade of steel (H-SA700 and conventional) used and the cross section shape (circular and square) of the column.  CFT columns using H-SA700 have about twice the elastic deformation capacity of conventional members. They can exhibit performance that exceed the full plastic moment based on superposed strengths theory. They also have sufficient plastic deformation capacities until their strengths decrease due to fracture, and local buckling of the steel occur. These results show that CFT columns using H-SA700 steel can be used as building structural members.