Introduction. Current Russian codes of design of reinforced concrete elements do not have rules and considerations for analysis of bent and compressed elements with irregular (not similar to rectangle) shape of cross-section under the action of shear forces. As result of previous investigations which were conducted in Research Institute of Concrete and Reinforced Concrete (NIIZNB) named after A.A. Gvozdev, new method of evaluating of the bearing capacity of inclined cross-section was proposed. Developed method has good matching with the results of experiments, conducted by Russian and foreign researchers. This paper deals with comparison of results of experiments with analysis by proposed model.

Aim. Further improvement of methods of analysis of strength of inclined sections of bent and compressed elements with irregular (not similar to rectangle) shape of cross-section under the action of shear forces. Comparison of proposed model with available data of experiments and results of numerical analysis.

Materials and methods. Theoretical investigations have been conducted on base of results of experiments, conducted earlier by Russian and foreign researchers for elements with circular cross-section. Totally, analysis has been performed for 13 samples with circular crosssection.

Results. Quality analysis of results of experiments and considerations of foreign codes has been conducted. Method of calculating of bearing capacity of bent reinforced concrete member with circular cross-section has been proposed. As a result of provided comparison of proposed method with data of experiments it was found out that proposed method provides required level of reliability – average rate of experimental bearing capacity to calculated value is 1.241 with standard deviation 0.123. It has been stated, that maximum deviation of results of calculation by proposed model was observed for samples with higher strength of concrete. As a result, it was recommended to provide additional investigations of samples with high strength of concrete, i.e. High Strength Concrete (HSC) samples (with strength greater than 60 MPa).

Conclusions. Method for calculating of the bearing capacity of bent reinforced elements under action of shear forces by the sloping crack has been proposed. When developing the methodology, continuity with current Russian regulatory documents in the part of elements with rectangular cross-section was taken into account. Proposed model has been checked with available results of experiment (totally 13 experiments of different authors). According to conducted evaluating of results of experiments proposed model provides enough reserve of reliability. To additional checking of reliability of high strength concrete members, it was recommended to provide additional experiments, I.e. for high strength concrete members.

Introduction. Ensuring of the joint operation of the reinforced structure and the reinforcement structures is a key factor for successful reinforcement of structures. Traditional methods of ensuring of the joint operation are not always applicable in practice. One possible method is to create concrete keys in the reinforced structure and transfer forces from them to steel key plates fixed on the reinforcement structures (beams) or vice versa (columns).

Aim. To illustrate the application of the method under consideration, we used the example of reinforcing of the monolithic reinforced concrete beams and steel columns.

Materials and methods. The reinforcement was carried out using modern construction materials, including Mapei construction chemicals, and modern methods, including laser cleaning of the surface of steel structures from corrosion products.

Results. It was found that the application of the method under consideration does not require unique qualifications from the performer, and the method is quite effective. The inclusion of reinforcement structures is indirectly confirmed by the results of structure monitoring, but due to the operating conditions of the structures, they have not been tested (including failure test).

Conclusions. The method discussed in the article can be recommended for use in difficult conditions. However, it is necessary to conduct an experimental verification by testing the structures to failure.

Introduction. This paper presents the results of experimental and theoretical studies of reinforced concrete cylindrical elements in a triaxially stressed state.

Aim. The main objective of this work was to analyze experimental data on the influence of various structural and force factors on the stress-strain state of prestressed reinforced concrete elements in a triaxially stressed state at all stages of their operation, as well as to develop a methodology for their calculation.

Materials and methods. The materials of previously performed experimental studies on prestressed reinforced concrete samples of cylindrical shape with stressed wire reinforcement wound along the side surface were used. The calculations were performed by the finite element method in a physically nonlinear formulation using the ATENA software package.

Results. The analysis of experimental data on the effect on the bearing capacity of cylindrical samples of the ratio of their geometric dimensions, concrete strength, degree of lateral compression. The features of the nature of deformation under load of samples in the cage, their behavior during repeated loading are considered. Computational finite element modeling of the operation of triaxially loaded cylindrical slabs at all stages up to destruction is performed, the results obtained and comparison with experimental data are presented.

Conclusions. Recommended values of geometric and force parameters have been determined, providing the most rational design solutions for thick slabs operating in a triaxially stressed state. A method for calculating such structures has been developed.

Introduction. One of the methods of rehabilitation of masonry walls is to cover them with a layer of special plaster solution, which is designed to: protect the masonry material from moisture; gradual removal of moisture from the masonry material through a layer of plaster in the form of steam. A very important parameter for facade plaster is its moisture permeability, that is, the ability to pass through moisture coming from the masonry material. In this work, a comparative study of two facade plasters was carried out: light mineral plaster "SPADAR SK-450" and heavy mineral facade leveling plaster (hereinafter referred to as FLP) according to their moisture permeability.

Aim. Comparative studies of the effect of moisture permeability of plasters ("SPADAR SK-450" and FLP) on the effectiveness of the dehumidification process of the aerated concrete base.

Materials and methods. For the study, samples of nonautoclaved aerated concrete with a layer of light mineral plaster "SPADAR SK-450" and heavy mineral plaster FLP were used. During the work, the following parameters were determined and compared: the change in the percentage of mass of the samples over time, after their water saturatio; the change in time in the density of the water vapor flow through the prepared samples; the dynamics of changes in the moisture content of the plaster coating.

Results. It was found that the density of the water vapor flow in the FLP plaster is maximum in the first 24 hours, followed by a dynamic decrease. At the same time, the density of the water vapor flow in the "SPADAR SK-450" plaster is almost uniform throughout the entire observation period with minor fluctuations.

Conclusions. It has been established that the light plaster "SPADAR SK-450" is more effective as a sanitizing plaster mixture in comparison with FLP plaster, as it promotes uniform gradual removal of moisture from the aerated concrete base without a significant increase in its own humidity. The uniform removal of moisture from the base through the "SPADAR SK-450" plaster layer helps protect against the formation of salts migrating with moisture from the base to the plaster surface.

Introduction. In two parts of the article, the conceptual and methodological issues arising in the calculations of reinforced concrete structures by the limit state method using a nonlinear deformation model according to SP 63.13330.2018 are investigated. The second part is devoted to the development of a mathematical apparatus and a computational justification of the new concepts introduced in the first part about the laws and diagrams of concrete deformation under compression and stretching conditions.

Aim. To develop and substantiate a calculation apparatus clarifying the provisions of the limit state method in terms of normalization of the "σ – ε" dependencies of concrete under compression and tension.

Materials and methods. The formal logic (analysis, synthesis, induction, deduction), methods of probability theory and mathematical statistics, the method of limit states.

Results. The inconsistency and imperfection of regulatory documents of the Russian Federation is shown: on the control of the uniformity of concrete properties; on the technical conditions of its use; on the technical conditions of cement as the main component of concrete; on the mechanical calculation of reinforced concrete structures. The coefficient of statistical transformation of the reference law of concrete deformation under compression – γ_с (for tension – γ_t) is proposed, which makes it possible to switch from the reference law to all other laws of deformation necessary in the calculations of reinforced concrete structures for two groups of limiting states.

Conclusions. To eliminate contradictions in the norms, it is necessary to introduce a single standard for the uniformity of the physical and mechanical properties of concrete, for example, to adopt V = 0.135 or another value developed and agreed upon as a result of discussion by the community of scientists and engineers. To tighten the uniformity requirements for cement, for example, to adopt V = 0.03–0.05, as it was previously regulated in Soviet standards. In order to fully normalize the strength and deformation characteristics of concrete, which are included in the dependences "σ – ε", it is necessary to normalize at least 7 parameters presented in the formulas of this article.

Introduction. Modern processes of metal production and building design require the introduction of precise automated solutions that meet international standards. The urgency of the work is due to the need to reduce time and energy costs, minimize defects and ensure compliance with regulatory requirements at all stages of production and construction.

Aim. Development of a methodology for integrating mathematical modeling with machine-readable standards (XML, JSON, OWL) to optimize technological and design operations.

Methods. Mathematical models based on the laws of thermodynamics, continuum mechanics, and optimization theory were used to formalize the processes; ISO/IEC standards and data structures in JSON, XML, and OWL formats to describe parameters (chemical composition of materials, melting modes, and structural geometry); automatic data verification algorithms, integration with BIM technologies (based on in the example of Revit) and the finite element method for calculations.

Results. The developed methodology allowed: reduce energy consumption by 15–20 % by optimizing melting and processing parameters; reduce the proportion of product defects by 25 % through modeling the casting and heat treatment stages; automate the verification of compliance with standards and the generation of project documentation in BIM environments; implement structured data exchange between systems via JSON and integration with the IFC format.

Discussion. The use of machine-readable standards and mathematical models has proven effective in reducing errors and resource costs. Automation of routine operations, such as checking standards and calculating structural characteristics, has become a key advantage. The prospects of the work are related to the expansion of the methodology to other industries and the development of OWL-based ontologies for complex production chains.

Conclusions. The integration of mathematical models with XML/JSON standards improves the accuracy of quality control in metallurgy. Design automation through BIM and machine-readable formats reduces the time required to create documentation by 30–40 %. The methodology provides scalability for the tasks of digitalization of industry and construction.

Introduction. Digitalization of the construction industry, including individual housing construction, is becoming a global trend. Digital Twin (DT) technology allows to create a virtual copy of a physical object and synchronize it with real data online.

Aim. To analyze the use of digital twins in private housing construction, identify the challenges of digitalization, and determine promising areas of development based on foreign research and case studies.

Materials and methods. The article is based on foreign research analyzing the technological architecture of a digital twin and the necessary software and hardware components for its creation.

Results. The analysis shows that creating a digital twin requires a carefully collected database (DataRoom), the integration of sensors, IoT devices, and analytical tools, as well as real-time data synchronization and AI model training based on the owners' behavior. Cloud platforms provide scalability for the system, but there are also barriers to implementation.

Practical significance. The article shows that digital twins of private homes are becoming part of the smart home concept, improving the operation and interaction of residents. It offers recommendations for real-time data processing, optimizing operational modes, adapting control to the behavior of owners, and intelligently predicting consequences.

Conclusions. The digital twin of a private house occupies an important place in the technological and social context, transforming approaches to construction and resident interaction. It combines the functions of a passport, a manager, and an analyst, making the house smart, adaptive, and secure, capable of responding to internal and external challenges, acting as a "digital shadow".