Experimental Investigation on the Vertical Ductility of Rectangular CFST Columns Loaded Axially

Abstract

A total of 5 steel and 21 rectangular composite concrete-filled steel tube (CFST) columns of moderate slenderness were tested to investigate their ductility under axial compression. The importance of the vertical ductility of columns was discussed, and a novel ductility measure was proposed and utilized to examine the ductility of tested specimens. The analyses showed that the ductility of axially compressed CFST columns highly depends on their failure mode. The key feature influencing the ductility is their ability to dissipate the energy of imposed loads. The larger the volume of a material that may permanently deform and consequently dissipate the energy, the greater this ability. In consequence, the ductility of specimens exhibiting local failure mode was higher in comparison to the columns that underwent global or mixed global—local failure. It was found that both steel and composite columns were able to carry axial loads in the post-critical state; but due to the limitations of local buckling of the steel cross-section in the concrete core and concrete confinement, all tested composite columns showed greater ductility than their steel counterparts.

Experimental Investigation of Special-Shaped Concrete-Filled Square Steel Tube Composite Columns with Steel Hoops under Axial Loads

“…However, the bending stiffness in the corner was large, and the deformation was small. Under the action of mutually perpendicular tension, strong constraints were formed on the core concrete along the diagonal direction [15,16]. At the same time, the above test phenomena revealed that the local bulge deformation of the specimen occurred mainly on the outside of the shaped steel tube.…”

“…However, the bending stiffness in the corner was large, and the deformation was small. Under the action of mutually perpendicular tension, strong constraints were formed on the core concrete along the diagonal direction [15,16]. Core concrete can be divided into effectively confined and ineffectively confined areas due to stirrups' restraint effects on core concrete.…”

Stability of Steel Columns with Concrete-Filled Thin-Walled Rectangular Profiles

“…At the present time, many numerical and experimental works (Alatshan et al [4], Chepurnenko et al [5], Grzeszykowski and Szmigiera [6], Florence and Senthil [7], Zhen et al [8]) are devoted to the topic of columns having hollow profiles filled with concrete. Storozhenko et al [9] performed experiments on high-strength composite columns subjected to eccentric loading.…”

Research on Confinement Effect of the Outer Steel Tube in Notched Square CFST Columns

“…Concrete-filled steel tube (CFST) columns have been widely used in heavy-duty structures or underground structures in recent decades, such as high-speed railway passenger stations, subways, and other underground structures [ 1 , 2 , 3 ]. The composition effect between the steel tube and infilled concrete in CFST columns enhances the axial strength and deformation performances.…”