## 2 Materials and Methods
### Methods  
The following methods were used during the study:  
* finite element modeling;
* experiment using a series of small-scale models in the amount of five pieces for each type of model;
* analytical calculation in accordance with regulatory documentation. Modeling was carried out according to the instructions of the regulatory and technical literature [17; 18; 19; 20]. According to the instructions of the design codes, the characteristics of the materials were assigned and controlled. When performing the simulation, the following simplifications were taken into account:  
* construction material has no voids and its properties are the same in all directions;
* stresses and relative deformations are interconnected by a linear relationship;
* cross sections of elements remain plane after deformation;
* the value of structural deformations is much less than their dimensions [21; 22; 23]. The calculation was carried out on the basis of SR 63.13330.2018 [7] analytically and in the Lira-Soft software package. For the most qualitative analysis of the bar structures' operation features, their numerical simulation was performed using the apparatus of the finite element method. The model is set in a spatial formulation. The work of the material elements is physically and geometrically linear. Since the displacements of design schemes are negligible compared to the linear dimensions of structures, we did not take into account geometric nonlinearity which is a disproportionate relationship between deformations and displacements. Two options for the cross-section of the elements (see Figure 2) and two options for applying loads on the bars are considered. As previously described, the cross sections are simplified to rectangular and tee shapes. The concrete class is taken equal to B25. To perform the experiment, small-scale models are taken with a scaling factor equal to 1:10. When performing analytical calculations of the work of a section on the action of internal shear forces, the method of sections is used. The considered rod is calculated in an arbitrary section, the action which is represented by the following forces: \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Sample** & **Code** & **Name of Material** & **Class** & **Specific Gravity, kN/m3** & **Design Compressive Strength, kPa & **Design Tensile Strength, kPa** & **Deformation Modulus, MPa** & **Poisson Ratio** \\ \hline
1 & SR63 & Heavy concrete Reinforcing steel & B25 & 25 & 14,500 & 1050 & 3\(\cdot 10^{4}\) & 0.2 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Characteristics of the materials used in the calculation. 1. Longitudinal force N;
2. Shear force Q;
3. Bending moment M.  
External forces are in balance with internal forces. Therefore, the whole system is in a state of static equilibrium. According to [22], the calculation of the rods for the transverse load is performed according to the equation:  
\[Q<Q_{b}+Q_{sw} \tag{1}\]  
where Q is the total shear force in the support section, arising from all external forces located on one side of the cross-section. By sequential enumeration, we find the most dangerous load value within the area from h\({}_{0}\) to 2h\({}_{0}\); Q\({}_{b}\) is the shear force that the concrete can carry; Q\({}_{sw}\) is the shear force that is perceived by the transverse reinforcement bars. By calculation, the most dangerous section is determined, in which the ratio Q/(Q\({}_{b}\) + Q\({}_{sw}\)) is maximum. As shown in Figure 3, the length of the studied section is taken to be at least 1.0h\({}_{0}\) and not more than 2.0h\({}_{0}\), where h\({}_{0}\) is the working height of the bar element [24]. The hinged supports of the ends were set as the boundary conditions. Loads were represented by uniformly distributed forces. However, for the purity of the experiment, the purpose of which is to clarify the effect of the concrete section on the perception of the shear force, it was decided not to use transverse reinforcement. Thus, Q\({}_{sw}\) is equal to zero.