Axial Compressive Behavior of Special-shaped Steel Fiber-reinforced-concrete Columns

What is it about?

Special-shaped columns are extensively used in residential and official buildings as they increase the efficiency of indoor space. However, many studies on normal special-shaped concrete columns demonstrate their poor ductility and requirement for additional reinforcement. To overcome these shortcomings, this paper presents a novel ＋-shaped column to enhance the ductile deformation. It integrates high-performance concrete with high-strength stirrups. To confirm the behavior of these columns, 10 ＋- shaped column specimens were tested under axial compressive loading. The parameters in this study are the spacing of the stirrups, the strength of the high-performance concrete, and the steel fiber content. The test results show that high-strength stirrups improve the axial compressive bearing capacity and ductility, and close tie spacing improves confinement, resulting in a significant enhancement of post-peak ductility with a moderate increase in column axial bearing capacity. Increasing the strength of high-performance concrete will not effectively enhance the ductility under large tie spacing. Steel fiber can enhance the bearing capacity and ductility, but higher steel fiber content does not significantly delay a decrease in bearing capacity. The analytical results are compared with tested values through the use of existing high-strength concrete and fiber-reinforced-concrete confinement models, and several parameters are discussed. The results indicate the need to develop special-shaped column-specific confinement models.

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