Load-bearing behaviour of columns of integral bridges – realistic calculation of columns of integral bridges for the ultimate limit state. Due to the complex and interactive load-bearing behaviour, calculation of integral bridges is more expensive than the calculation of bridges with its superstructure uncoupled from the substructure. Apparently conservatively chosen reinforcement ratios lead to increased stiffness of the columns and thus inherently increased the constraining forces. Therefore, a greater reinforcement ratio is not imperatively connected with a better load-bearing behaviour of the columns. To better understand the load-bearing behavior of integral bridges, it is necessary to consider the physical non-linearity in the calculation. In this contribution, the non-linear behaviour of integral columns is examined by varying the cross section dimensions and the reinforcement ratios. The results are analyzed with regard to the columns ductility and the constraining forces. Finally, this contribution offers conceptual proposals, which can be used for the dimensioning of integral bridges.