## 3 Bending of Slab Supported by Column
The bold values are also correct for initial \(b=30\) cm, so they coincide with the distributions displayed in Figure 10. Figure 13 presents the diagrams of the bending moments \(m_{xx}\) in the slab panel cuts for two extreme cases of the applied column size: the smallest, \(20\) cm, and the largest \(44\), cm. It is observed that the reduction region of the moment \(m_{xx}\) is derived from the column size. The idea of determining the reduction zone in Robot to limit the values of \(m_{xx}\) around the column is illustrated in Figure 14. The method is demonstrated for the mesh with square FEs and different column cross sections. First, the reduction radius is evaluated based on half of the diagonal of the column's cross-section. Then, the nodes and the centers (here marked in yellow) of FEs that are inside the circle are selected. The primary bending moment values are replaced with the reduced ones at all these points. The interiors of the light pink areas limited by the red lines are subjected to this reduction. The extreme (maximum or minimum) of the bending moment is found among the values at the nodes marked in orange. For example, in the drawings in Figure 14, this refers to the node highlighted additionally in cyan. Finally, such a value is imposed on the reduction area. \begin{table}
\begin{tabular}{c c c c c c c c} \hline
**Size of column** & [cm] & 20 & 22–24 & **26–32** & 34 & 36–42 & 44 \\ \hline
**Moment \(m_{xx}\)** & [kNm/m] & 13.816 & 12.720 & **11.933** & 11.320 & 10.600 & 10.219 \\
**Integral \(I_{mxx}\)** & [kNm] & 29.014 & 28.620 & **28.315** & 28.002 & 27.612 & 27.361 \\ \hline \end{tabular}
\end{table} 
Table 3: Influence of column size on reduced bending moments \(m_{xx}\) in slab center, results for Robot and mesh with 64 FEs alongside. Figure 13: Panel cut diagrams of bending moment \(m_{xx}\) in slab for two extreme cases of applied column size: \(20\) cm (left) and \(44\) cm (right), results for Robot and mesh with 64 FEs along side. In the Midas program, during the calculation stage, there is no option to directly adopt reduction. Therefore, to apply the reduction in the model, the slab reinforcement has to be predefined. Arbitrarily, the entire slab is designed with \(\varnothing 10\) reinforcement bars spaced at 20 cm at the bottom and \(\varnothing 10\) bars spaced at 10 cm at the top, in both directions, \(x\) and \(y\). The concrete cover is equal to 3 cm. It should be emphasized that, in this configuration, the upper layer of the slab is subjected to tension. Of course, now the reinforced slab has greater stiffness. After computations, there are two modes available for reviewing the results in the Midas interface: static analysis or dimensioning. In the post-processing stage, the reduction option operates only in the dimensioning mode. Table 4 presents the influence of mesh division on the slab's moment reduction in Midas. The third column of numbers shows the maximum \(m_{xx}\) values for the slab without rebars and, thus, also without reduction. Similarly to the results for Robot in Table 2, these values increase with mesh densification. The results for the same slab, but with the reinforcement, are presented in subsequent columns. The reduction distance from the column axis should be specified for the RC slab, and here, it will be referred to as width \(W\). The bending moments are presented for the cases \(W=0\) cm, \(W=50\) cm, and \(150\) cm, respectively. Blank cells in Table 4 for \(256\times 256\) FEs indicate that these computations could not be completed for the finest mesh due to sudden interruptions, even after restarting the task from the beginning. Nevertheless, activating the reduction via the given width leads to a decrease in the moment \(m_{xx}\) at the slab-column connection. For the reduction option with \(W=50\) cm and \(150\) cm, each successive mesh refinement tends to a specific value of the slab's bending moment. For \(W=50\) cm, the moment \(m_{xx}\) eventually exceeds \(12.5\) kNm/m, while for \(W=150\) cm, it approaches approximately \(9.3\) kNm/m.