The relevance of the study is due to the fact that: firstly, the proposed topic is in line with the Government-approved "Strategy for the development of the construction industry and Housing and Communal Services of the Russian Federation for the period up to 2030 with a forecast up to 2035" dated October 31, 2022, which assumes an increase in the share of industrial housing construction, including panel construction; secondlySecondly, the existing methods for calculating the joints of panel buildings have come down to us almost unchanged from the level of development of construction science and engineering in the 1980s. of the last century, which leads to increased material costs and rising real estate prices, therefore, the current trend in the development of the construction industry requires the improvement of these techniques. Modern approaches to nonlinear modeling and calculation of reinforced concrete will allow, in relation to panel joints, to reveal the reserves of their bearing capacity and obtain a more rational design, which will reduce the cost of constructing the buildings in question as a whole. PURPOSE. To carry out a comparative analysis of existing methods for calculating panel joints in two groups of limit states, to identify their advantages and disadvantages. Identify ways to improve them. METHODS used in the course of the research: theoretical methods – chronological, formalization, classification, analysis, synthesis, generalization, comparison. RESULTS. The analysis of existing methods of foreign and domestic design standards, as well as various author's methods, showed that: 1) foreign and domestic standards are based on the limit state method; 2) the nonlinear deformation model is not used in the calculation of joints of reinforced concrete panels; 3) to obtain a more accurate VAT of reinforced concrete panel joints, it is necessary to process a large amount of data using computer technology. CONCLUSION. The analysis shows that the use of computer software systems is the most promising method for calculating building structures, allowing fast and accurate calculations, reducing the cost of construction.

Keywords: large-panel construction, reinforced concrete, panel joint, joint calculation, joint classification, platform joint, deformation model, limiting forces, computer modeling, finite element

Ring-shaped reinforced concrete structures are widely used in construction. For example, in the form of underground pipelines. They experience a complex nonlinear deformed state (VAT), which is analytically described as a complex mathematical problem of mechanics. Therefore, numerical methods are often used to solve it. This article uses the finite element method (FEM) implemented in the Lira-CAD 2022 PC. The VAT of reinforced concrete pipelines is determined in a physically nonlinear formulation, taking into account 4 factors of influence: the inner diameter, the concrete class, the properties of the filling soil, and the properties of the foundation soil. A plan has been drawn up for a complete multifactorial numerical experiment, which includes 81 models. The values of internal force factors in all sections of the underground pipeline are obtained, taking into account the variation of each factor individually and taking into account their mutual influence. Combinations of factors giving extreme values of internal forces in the pipeline have been established. Based on this, recommendations for rational design have been developed.

Keywords: underground pipeline, reinforced concrete, computer modeling, longitudinal profile, cross section, PC "Lira-CAD"