In the final paper, the bending of the I profile in the elastic and plastic region was analyzed. The analysis of different sections of the profile in the elastic-plastic region, the determination of the factor of increase k in the plastic region for cross-sections, how to increase the load capacity of a solid flat support in the plastic region, and how much plastic deformation is allowed will be presented. On the given example, the selection of the I profile will be made, which will have to meet the conditions of the load-bearing and stiffness criteria. For the obtained I profiles, the stress distribution for the elastic area at the appearance of a plastic joint, the increase in load capacity in accordance with Eurocode, and a comparison of the mass of the selected I profiles will be shown. By selecting the I profile as the first selection, the profile with the smallest mass per meter will be chosen, and the conclusion will explain why it is the most favorable and what to do in case the profile does not fit during construction.