The article discusses the results of the analysis of the stress-strain state of the junction of the column and the beam of a monolithic reinforced concrete frame - in particular, the cornice nodes of the outer columns, which have an L-shape. In these nodes, part or all of the tensile (upper) reinforcement of the beam, bending along a certain radius R, passes into the column. The subject of the study is the stress state of concrete in the frame node, as well as the features of the operation of the curvilinear section of the tensile reinforcement. The study of the features of the concrete operation was carried out by setting up a computational experiment. Modeling was performed in the Lira-SAPR software package. The characteristics of the model (finite element scheme) and the main results of the calculation are given - the distribution and numerical values ​​of stresses. To assess the actual work of the tensile reinforcement of the node, an analysis was made of the influence of the loading history of the reinforcement bar - its plastic bending to give the required outline. It was established that the stress state of concrete of a bisecting section differs fundamentally from the stress-strain state of concrete in normal cross-sections of a beam and a column. Taking into account the loading history of the reinforcing bar (preliminary inelastic bending) allowed us to conclude that, with the same tensile force, the deformations of a pre-bent bar exceed the deformations of a rectilinear bar. Obviously, this circumstance leads to an increase in the crack opening width.

Keywords: ramny node, reinforced concrete, reinforcement, stresses, deformations, bisector section, normal section, plastic bending, bending radius, loading history, finite element, Lira-SAPR

The article presents the results of experimental tests of a number of reinforced concrete eccentrically compressed structures reinforced with composite materials in the longitudinal and transverse directions. During the study, it was found that the composite external reinforcement does not work the same in reinforced concrete structures, but depends on the area of ​​​​the composite materials on the structure. This is due to different stress concentrations along the length of reinforced concrete structures from the action of bending moments and transverse forces. The consequence of this uneven stress state in composite materials is their premature delamination and an underestimation of the overall efficiency of the reinforcement system. This article presents the results of experimental data on the values ​​​​of relative deformations εf of composite materials of reinforced concrete pillars, flexibility λh = 10, tested at a large eccentricity of load application (e0 = 4 cm or 0.32h), going beyond the core of the section. This paper considers various options for composite reinforcement located both in the longitudinal and transverse directions. The deformations were recorded by strain gauges with a 2.0 cm base, at all load levels. As a result, the maximum relative deformations of composite materials were recorded, the most effective zones of transverse clamps location and places where deformation along the fibers did not develop were identified, therefore, the composite in the reinforcement system did not work. The obtained data make it possible to develop the most rational reinforcement options.

Keywords: concrete, reinforced concrete, composite material, carbon fiber, external reinforcement, deformations, compressed elements

The existing classification of social objects is considered, using the example of school buildings with a link to the capacity of pupils and the location in settlements of different types. The key external and internal factors that influence the decision of the construction organization to sign a contract for the construction of school institutions are identified, the problem is described - insufficient transport accessibility, lack of resource base, Construction time lag in the implementation of social projects. The influence of the chosen design solution, as well as climatic conditions on project implementation dates was considered.

Keywords: classification of social purpose objects, influence of constructive decisions on the realization of construction object, the ratio of transport accessibility of regions, supply of resource base

The schematic solution of the heating system is analyzed, as well as possible variants of design solutions. A multi-variant hydraulic mode of operation of the heating system of an apartment building is simulated on a simulator stand. The results of the experimental study are presented, and based on the change in design costs and the value of the adjustable pressure drop in parts of the system, proposals are made that allow reducing the cost of water heating systems of buildings under construction, as well as suggesting an increase in the simplicity of adjustment and quality of system regulation.

Keywords: water heating system, oxygen permeability, gas permeability, polymer pipes, gas solubility

This article presents the results of experimental study of the strength of wood and concrete specimens under local buckling by a flat die under short-term loading action. At joint operation of a reinforced concrete slab and a timber beam in the connection there is buckling of timber and concrete elements, therefore it is necessary to know values of strength at these types of loading of timber and concrete. The strength values of timber, concrete on expanded clay aggregate, compression and buckling strength ratios of materials, as well as physical properties of materials according to the requirements of normative documents have been determined. The values of timber deformation were obtained and the graph of deformation dependence on stresses and graphs of deformation growth were plotted; the coefficient of soil stiffness was obtained to determine the strength for local crushing of materials

Keywords: short-term loading, strength, flat die, compression, buckling, coefficient of subgrade reaction, timber, concrete

The article presents a method for determining the stress-strain state of pile foundations for metal supports of power transmission lines during technical examination of power grid facilities in the Far North. An example of calculation using the LIRA automatic software package is given. The most stressed sections of structures are determined. The prospect of using CAD during technical examination of power grid facilities is proved.

Keywords: building structures, metal structures, energy facilities, stress-strain state, technical expertise

The paper considers the experience of using neural networks in construction. The widespread coverage of AI success in various areas of construction has led to an increase in business and public interest in the successful implementation of AI in various construction areas. Examples of the use of neural networks in the construction expertise of the working documentation "Metal structures" and "Metal detailed structures" are given. The process of solving the assigned tasks by an expert builder in comparison with the answers received by the neural network is described. A comparative analysis of the quality of the results obtained by the expert builder and artificial intelligence is given. As part of this study, the main algorithms for training neural networks that are applicable to solving the problem were analyzed. Particular attention is paid to algorithms capable of efficiently handling parameter variations and new configurations not represented in the training dataset. The use of these algorithms will provide increased accuracy when scaling the solution. A neural network forecast for this area of construction expertise is given.

Keywords: neural network, construction, construction expertise, expert builder, comparative analysis, training sample, neural network forecast

The article examines modern construction technologies used in the North Caucasus region of Russia and their impact on the efficiency and sustainability of the construction industry. In the context of growing economic and environmental challenges, as well as changing social needs, automation is becoming a key factor in optimizing construction processes and project management. The main focus is on the analysis of the current state of the construction sector in the North Caucasus, its main problems and prospects for the application of new technologies. Innovations such as Building Information Modeling (BIM), robotics, drone technologies, 3D printing of buildings and the use of Internet technologies for monitoring and managing construction processes are considered. Examples of the successful application of these technologies in various projects in the region are described in detail, which allows us to assess their impact on the productivity and quality of work performed. The article also examines the issues of financing the implementation of innovations, training personnel and creating the necessary infrastructure to support automation. The barriers and challenges that contractors and construction companies face when switching to new working methods are considered. Attention is paid not only to economic but also to environmental aspects - how automation can help reduce the impact of the construction industry on the environment. In addition, the paper presents a forecast for the development of the construction industry in the North Caucasus, taking into account new technologies, as well as recommendations for their implementation to achieve sustainable growth and increase the competitiveness of regional construction. Given the specifics and needs of the region, the emphasis is on the possibility of adapting global trends to local realities. Thus, the article emphasizes the importance of innovative automation technologies for the modernization of construction production in the North Caucasus, their role in increasing the efficiency and sustainability of the industry, and also offers strategies for the successful implementation of these technologies in the conditions of a particular region.

Keywords: construction, additive technologies, modern trends, construction production technologies, construction industry, additive technologies, ecology, construction processes, North Caucasus

This paper is the first of a series of works, which the authors have devoted to the analysis of experimental data available in the literature on the influence of various factors on the strength of reinforced concrete monolithic walls of civil buildings. Among them the most significant ones were identified: the ratio of height to wall width, the ratio of height to wall thickness, the class of concrete and the class of reinforcement, the reinforcement scheme and the loading scheme, etc. The most important factors were identified. It is established that the scientists of the past and present in their works, due to the complexity and costliness of experiments, considered a limited small number of factors in a separate study - 1...3, often without taking into account their mutual influence. There is no theoretical interpretation of the results obtained in these works, and no scientific publications summarising the accumulated experimental material have been found. This paper and our subsequent publications are an attempt to eliminate this gap. In the present paper, a classification of all factors is given and the joint action of factor No. 1, which takes into account the H/B aspect ratios, and factor 15c, which takes into account the joint action of vertical and horizontal loads, is considered. The results of this analysis will allow us to make the next step towards the improvement of the methodology for calculating the strength of monolithic reinforced concrete walls, which will take into account the different types of influencing factors as much as possible.

Keywords: reinforced concrete, monolithic walls, experimental data, strength, stiffness, crack resistance, influence factors, geometrical parameters, loads, deformations

This article presents a new method of strengthening reinforced concrete columns using metal and composite materials. The analysis of existing traditional and modern methods of strengthening of reinforced concrete compressed elements has been carried out and their main disadvantages have been identified, taking into account which a new reinforcement method has been developed. This study presents the results of testing the effectiveness of a new reinforcement method, describes in detail the basic schemes, technology and procedure for performing reinforcement work. The results of the conducted experimental studies are presented. The strength of the control samples was compared with the reinforced ones. Proposals have been developed to strengthen reinforced concrete columns with metal elements arranged longitudinally and composite materials glued in the form of clamps with fibers arranged in the transverse direction.

Keywords: steel, reinforced concrete, heavy concrete, test, rack, composite material

The article considers the parameters of rational use of additional support faces of reinforced cylindrical mesh shells. The assessment of the features of shaping has been carried out and the choice of the topology of surfaces within the limits of ensuring the stability of the structure has been justified. Recommended ratios of overall dimensions are proposed and corresponding calculation models are formed. The criteria for determining the sensitivity of the grid are given, taking into account additional support faces and the fulfillment of the conditions of limit states. A range of acceptable values of curvature and geometric parameters for the creation of reinforced cylindrical mesh shells has been obtained. The effect of increasing stiffness and increasing height on the performance of the mesh surface is analyzed. The characteristic patterns of changes in nodal deviations and internal force factors of vulnerable zones are revealed.

Keywords: cylindrical mesh shells, additional support surfaces, shaping, parameter ratios, reinforcement, stability

The article provides a brief overview of foreign experience in the application of information modeling technologies (BIM) in "green" construction. The work carried out a scientometric assessment of publications on the topic of BIM in "green" construction. As a result of the review, it was found that BIM has recently been increasingly used in the field of "green" construction, forming a new stage of resource efficiency and minimizing the negative impact on the environment.

Keywords: information modeling technologies, "green" construction, sustainable development, building life cycle, resource management, energy efficiency and environmental friendliness

Modern designs of water heating systems are saturated with different types of regulators, but their use is more often justified not by a systematic approach, but by solutions necessary for the operation of the system in its individual parts. The objectives of the presented work are to obtain and systematize experimental data to study the variable hydraulic mode of operation of horizontal water heating systems using apartment stations. In this paper, a problem in the field of development of modern water heating systems that needs to be solved is formulated. The analysis of the schematic solution of the heating system, as well as possible design options, was carried out. A simulation of the multivariate hydraulic mode of operation of the heating system of an apartment building was carried out on the simulator stand. The results of an experimental study are presented, and based on changes in design costs and the value of the adjustable pressure drop in parts of the system, proposals are made to reduce the cost of water heating systems for buildings under construction, as well as suggesting an increase in the ease of setup and quality of system regulation.

Keywords: balancing fittings, hydraulic characteristics research, water heating system, automatic regulators

The development of methods for calculating structures made of ultra high-performance steel fiber-reinforced concrete (UHPC) in terms of strength and deformations is an important step towards the introduction of this innovative material into the practice of design and construction. This paper presents the results of finite element modeling of the operation of UHPC I-beam in the area of action of shear forces. The SMM model integrated in the OpenSees framework application is used for the walls of beams under conditions of flat stress. The authors have added new classes of materials that implement the averaged deformation laws of UHPC (with and without fiber) and the reinforcement placed in it. The calculations showed good convergence with the authors' own test results of the UHPC I-beams, as well as with the results of experiments by other researchers.

Keywords: shear strength, shear force, ultra high-performance steel fiber-reinforced concrete, I-shaped beams, OpenSees

The choice of the method of force calculation of building structures is preceded by an analysis of the static determinacy and immutability of the rod system using structural formulas, while for different types of structures - for beams, trusses, frames, arches, etc. - sources offer different formulas. It is shown that for the structural analysis of all rod systems it is sufficient to determine the degree of structure anomaly using the formula of P.L. Chebyshev. The development of the linear-monad theory of structure makes it possible to formalize the dependence of the number of rods and hinges on the number of external and internal contours in the synthesis of both normal and anomalous structures

Keywords: beam, truss, frame, arch, structure, analysis, synthesis, immutability, definability, degree of anomaly, rods, system, contour, monad, hinge

The situation of occurrence, identification and management of risks arising during the construction process is analyzed. Uncertainty of decision-making in construction projects involves the creation of methods that ensure the reliability of decisions and their effectiveness. Such a method was developed in the Russian Project Management Association. The paper provides an example of using this method on a real construction site. An analysis of risks arising during the implementation of a construction project was conducted, a risk map was created for this project and the PERT method was applied when creating a calendar plan.

Keywords: uncertainty, risk event, probability, risk, damage, danger, reliability, risk analysis, investment and construction project, PERT method

Based on the results of experimental studies of the propagation of bending waves, the ability of the developed technique to assess the strength of a brick treasure is considered. A comparative analysis of the strength of the masonry was carried out using different methods (L.I. Onishchik formula, Eurocode 6). According to the correlation dependencies between the velocity of propa-gation of elastic waves and the strength of masonry, the presented practical data made it possible to prospectively evaluate the method using bending waves in the survey of buildings and struc-tures.

Keywords: experimental studies, brickwork, elastic waves, bending wave velocity, strength

The method of determining the stress-strain state of metal poles of power transmission lines during the technical examination of electric grid facilities is analyzed. An example of a calculation using the automatic LIRA software package is given. The most stressed sections of structures are determined. The calculated method confirms the hypothesis that the triangular cross-section of the traverse of the portal intermediate support of the 500 kV overhead line is more economical (more efficient) than a tetrahedral (classical) cross section.

Keywords: building structures, metal structures, energy facilities, stress-strain state, technical expertise

Providing the population with comfortable housing has always been a pressing issue. However, there are very few formalized criteria for this, apart from the regulation of minimum floor areas. In this context, the article deals with the problem of evaluating the efficiency of residential space design solutions in terms of their logistical comfort. For this purpose, a method is proposed that uses the apparatus of graph theory and allows to calculate the time cost of an "idle" move for a representative of a given social group in relation to the evaluated design solution. An idle move is a user's movement between characteristic functional zones of the layout. A special matrix is used to model the links between these zones, the construction of which is similar to that of the incident matrix in undirected graphs. As an example of the applicability of the proposed approach, several variants of layouts of one-room, two-room and three-room flats are considered. The comparison of the obtained results for different types of layouts, including those that existed 15-20 years ago and modern ones, indicates a tendency to increase the logistic comfort of modern layouts.

Keywords: planning solution, logistic comfort, idling, graph theory

Advanced nuclear power technologies such as small modular reactors (SMRs) and micro-reactors, a subset of SMRs, have the potential to play a key role in the coming nuclear power expansion. Connect with technical innovators, manufacturers, designers, and government regulators to discuss advancements and gain insights on the latest AMR and SMR projects in the UK and globally. 2024 year's world patents are presented.

Keywords: nuclear technology, small modular reactor, micro-reactor, modern patents

Authors considered the thermal inertial properties of some building envelope constructions which included the changes of internal surface layer materials. Researchers described the thermal and physical characteristics of 6 building surface layer materials. It has been determinate the radiant temperature of building envelope inside surface with changes of wall construction after 225 hours cooling process and initial temperature equal to +23 оС. Authors defined the cooling time of building envelope inside surface to 0 оС at different types of surface layer materials. Numerical experiment was done with modern program complex “Stf”. Modeling process was completed in program which was realized with finite difference method and constant heat transfer coefficient. There are new experimental results which were determinate during the research and realizing the mathematical model of non-stationary element’s cooling process. Results could be interested for researchers of thermal phenomena in building envelopes and designers of microclimate engineering systems in buildings and structures.

Keywords: air temperature, radiation temperature, stationary regime, non- stationary regime, building envelope, emergency regime, thermal inertia, inside surface layer, program, building materials

The article shows the importance of analyzing the state of strength properties of old wood during restoration work and monitoring the state of the structure. In particular, the physical and mechanical properties of wood during long-term use in an aquatic environment are analyzed. Changes in the chemical composition of wood as a result of use in the water of the Gulf of Finland are determined. Using the example of logs of the crib foundation of the Kronshlot fort, it is described how a change in the chemical composition of the material affects its strength properties.

Keywords: Mechanical properties of wood, long-term strength, chemical composition of wood, water-soluble extractive substances

Slag-alkali binder (SAB) is obtained by polymerization of granulated blast-furnace slag (aluminosilicate component) ground in a ball mill with an alkali activator, resulting in an environmentally friendly hydraulic polymer binder. Slag-alkali concrete (SAB) based on SAB has become an alternative to traditional concrete based on portland cement (PTC). Reinforcement bars in combination with SAB make it possible to obtain concrete structures with high adhesion properties to reinforcement compared to concrete based on portland cement. However, due to differences in the production process of SAB, there are obvious differences in technical properties, including adhesion characteristics. However, proper standardization is needed for its production and operational testing to limit contradictory results in the laboratory and on the construction site.

Keywords: metallurgical waste, granulated slag, crushing, chemical activation, reinforcement, adhesion, strength

The rocks that form a natural geological reservoir for underground gas storage, during the operation of UGS, are exposed to prolonged cyclic loads caused by periodic injections and withdrawals of natural gas. At the same time, it is possible to develop and accumulate residual deformations in rocks that cause irreversible changes in the properties of rocks and this must be taken into account when designing and operating UGS.

Keywords: underground gas storage, geomechanical modeling, cavern, salt massif, deformations

Geopolymers and alkali-activated materials are cement-free composites formulated by activating alumino-silicate materials, such as fly ash, meta-kaolin, and silica fume, and calcium-rich materials. The Geopolymer Materials Market grew from USD 12.48 billion in 2023 to USD 15.69 billion in 2024. It is expected to continue growing at a CAGR of 29.46%, reaching USD 76.07 billion by 2030. Today we found about 750 patents of USA, China, Japan and other countries. The selected last year patents have emerged on the usage of geopolymeric mortars for 3D printing, grouting, sewage lining, and wastewater treatment.

Keywords: geopolymers, alkali-activated materials, market of geopolymers, patents on geopolymers, application in in civil engineering