Study on the Eccentric Compression Performance of Stiffened Rectangular CFST

Abstract

Concrete-filled steel tubular columns (CFST) have high bearing capacity, high stiffness and good ductility. The columns with rectangular section are more suitable for compression bending than round. However, its lateral binding force is small in the middle of the section, and local buckling is easy to occur.Stiffened Rectangular Concrete Filled Steel Tubular columns(SRCFST) are proposed to solve the problem that ordinary rectangular concrete filled steel tubular columns(RCFST) are prone to appear local buckling before reaching the limits of carrying capacity in 3 cases such as the thin steel tube wall, the larger diameter to thickness ratio or width to to thickness ratio. SRCFST are RCFST added with stiffening ribs, stiffening hoops and binding bars. By its set, the latera stiffness and the resistance ability of the local buckling of the steel tube are effectively enhanced, so the confinement effects of the steel tube to core concrete become stronger and more uniform. To compare the improved effects of SRCFST and RCFST with binding bars under eccentric compression, the paper compiles the solving procedure of the cross section grid unit method which can accurately solve the whole process curve of SRCFST under eccentric compression. The whole process curves show that the eccentric bearing capacity and ductility of SRCFST are obviously improved with respect to RCFST with binding bars.