Wpływ stateczności zbrojenia podłużnego na zachowanie słupów żelbetowych o przekroju prostokątnym

The onset of buckling of longitudinal bars in reinforced concrete columns is a key damage pattern. On the other hand, buckling of longitudinal bars is not accounted for in typical sectional analyses for column section in plastic hinge region. Results of numerical analyses dealing with elasto-plastic buckling of reinforcing bars and results of the numerical moment-curvature prediction for RC columns are presented in the paper. It follows from the obtained results that: a) the postbuckling path of reinforcing bars depends on the slenderness ratio and on the material properties of steel, b) the increase in the tie spacing results in a significant improvement in strength, ductility and energy-absorption of RC columns, if the tie spacing is smaller than nine dia.