Damage of concrete columns reinforced with grouting‐filled steel tubes under static loading

The purpose of this study is to examine the experimental, numerical, and analytical behavior of a novel class of composite columns. These columns are designed to replace conventional deformed steel bars with small circular steel tubes filled with cementitious grouting material in a longitudinal orientation. Twelve concrete columns in all were assembled and tested under various loading scenarios. These columns were evaluated under concentric compression load, two eccentric compression loads (25 or 50 mm), and flexural load. They included various forms of reinforcement in a longitudinal direction, including steel bars or tubes. A developed three‐dimensional finite element analysis utilizing the ABAQUS software and a suggested nonlinear sectional analysis methodology was validated using tested specimens. The test findings showed that the columns reinforced with 16 mm diameter steel tubes, whose wall cross‐sectional area is equal to 30% of the steel bar's area, were able to attain an ultimate capacity that was 77% of the conventional column specimens. Furthermore, compared to specimens reinforced with steel bars, the experimental load capacity of the specimens with 25.4 mm diameter steel tubes reinforcement—where the tube's wall cross‐sectional area and the steel bar have the equivalent area—was marginally higher. Finally, the proposed analytical methodology and the developed FE model employed in this study can accurately replicate the behavioral histories of concrete columns evaluated under various loading circumstances.