Abstract
The shear strength and other behaviors of RC short columns against shear reversals are investigated by experimental and analytical studies. In the experimental study, it was observed that RC short columns which carrly arge axial load are likely to fail due to cumulative axial subsidence at the axial loading point caused by shear reversals, and that tie reinforcement has little effect to prevent this phenomenon. The analytical study was carried out to investigate this phenomenon and to make clear the design consideration for preventing the cumulative axial failure of RC short columns. As the bases of analytical study, truss analogy of bearing mechanisms was considered, and the slip failure envelope which was used in the shear transfer theory was applied to obtain the ultimate strength of core concrete. The behaviors of RC short columns that was observed in the experimental study were well explained analytically and it is deduced that the cumulative failure of RC short columns is caused by the compressive yielding in main bars after shear slip occurs in core portion, where the compressive stresses caused by axial and bending forces are resisted by main bars only. As the cumulative failure could not be prevented by tie reinforcement, it would be concluded that RC short columns should not be subjected to axial loading which causes main bar yielding.
