Introduction. A nonlinear numerical analysis of a monolithic ribbed multi-span floor slab was performed to assess the influence of corrosion damage to reinforcement and concrete on the stress-strain state. Corrosion damage to the reinforcement was taken as a 25 % loss of the bar cross-section along 70 % of the beam length. Damaged concrete was assumed to have a strength class of B5.

Materials and methods. Finite element models of full-scale tests were developed and their verification numerical calculations were performed. A finite element model of a fragment of the ribbed floor slab using solid finite elements was developed for stress-strain state analysis. The laws of nonlinear deformation for concrete and reinforcement were taken into account.

Results. Tensile stresses in the reinforcement bars were obtained for both the corrosion-damaged and undamaged models. Based on these results, graphical dependencies illustrating the redistribution of forces in the monolithic beams were plotted. A comparative analysis of deflections and the size of the compressed zone of the slab in the damaged and undamaged numerical models was performed.

Conclusions. The qualitative influence on the redistribution of forces in monolithic corrosion-damaged and undamaged beams was determined based on the criterion of plastic hinge formation. An increase in deflection and the size of the slab’s compressed zone by 23 % was identified in the damaged models.

Introduction. A separate category includes river-bed pressure buildings of hydroelectric power plants. Such buildings include reinforced concrete piers, beams, pressure walls together with the floors of machine rooms, foundation slabs, etc. At the same time, as an integral element, they have inter-block construction joints. During the long-term operation, problems arise, which lead to a decrease in the operational characteristics of reinforced concrete structures of hydroelectric power plant buildings.

Materials and methods. The reinforced concrete structure of the Tishrin hydroelectric power plant’s channel pressure building was modelled using the finite element method to determine the stress-strain state under the influence of an earthquake with an intensity of more than 8 points. The corresponding calculations were performed based on dynamic theory using accelerograms.

Results. The calculations of the stress-strain state of the reinforced concrete channel pressure building of the Tishrin hydroelectric power plant showed that the opening of the inter-block construction joints, the contact joint between the base of the hydroelectric power plant building and the foundation, and the formation of cracks in the monolithic part occur under the influence of tensile stresses.

Conclusions. Based on the results of the calculations, it was necessary to reinforce the reinforced concrete structures of the Tishrin hydroelectric power plant, for example, by using pre-stressed composite reinforcement.

Introduction. The pressure walls of the machine rooms and the shield walls of the reinforced concrete channel buildings of hydroelectric power plants/pumped-storage hydroelectric power plants are subjected to the pressure of the upper/lower water level, which is transmitted to the floors and other structures of the buildings. The condition of the structures of long-term operated reinforced concrete channel buildings of hydroelectric power plants/pumped-storage hydroelectric power plants may require their reinforcement, for example, with external reinforcement made of carbon composite materials.

Materials and methods. The load-bearing structures of the reinforced concrete channel buildings of hydroelectric power plants and pumped-storage power plants were installed, and their condition may require reinforcement. Laboratory tests have been conducted on models of a section of the upper wall of the machine hall of a reinforced concrete channel building of a hydroelectric power plant at a scale of 1:15 (without reinforcement and with reinforcement using carbon composite tape on the stretched edge). Numerical finite element methods are used to conduct computational studies of the stress-strain state of the channel building of a hydroelectric power plant/pumped-storage power plant.

Results. The experimental studies demonstrated a significant positive effect of external reinforcement on the displacement of the top of the models, the opening width of the inter-block joints, and the stress in the tensioned reinforcement within the joints. A three-dimensional mathematical model of a river-bed hydroelectric power plant was developed for computational studies.

Conclusions. The condition of the structures of long-term operated reinforced concrete channel buildings of hydroelectric power plants and pressure buildings of pumped-storage hydroelectric power plants may necessitate their reinforcement, for example, with external reinforcement made from carbon composite materials. Based on the results of the laboratory studies, the method of reinforcing the structure of the upper wall of the machine hall of a reinforced concrete channel building of a hydroelectric power plant using carbon composite tapes was validated. A three-dimensional mathematical model of a hydroelectric power plant channel building was created to conduct computational studies.

Introduction. The digitalization of the construction industry and the introduction of information modelling (TIM) technologies require the development of new approaches to the evaluation of working documentation. Traditional methods of manual verification are time-consuming, subjective and do not provide reproducible results. This paper proposes a method for intelligent evaluation of working documentation prepared using information modelling tools, based on formalized logical rules and neural network analysis.

Materials and methods. The methodology implements a two-channel approach: parallel assessment of the digital model and textual and graphic documentation. It is based on a multi-level structure of indicators, a logical Boolean model, as well as a neural network architecture that includes a graph subnet (GNN), a text subnet (BERT) and a convolutional subnet (CNN), combined into a multilayer classifier. As a result, there are four discrete decisions: adopted, adopted with revision, sent for revision, refusal to accept. The possibility of working with an incomplete set of documentation is taken into account. Verification of the methodology was carried out using an expert survey.

Results. A mathematical model has been developed that describes the logic of evaluating documentation by performance criteria, percentage compliance and quantitative metrics. Expert validation showed a high consistency of assessments (W ≈ 0.52), especially in the logic of the structure, division into critical groups and two-channel. The most problematic aspects are the architecture of the neural network and feedback.

Conclusions. The methodology proved its applicability for the tasks of internal audit, automation of control over the acceptance of documentation, preparation for examination and assessment of the degree of readiness of working products. The development of
the model is possible through the clarification of the architecture and the expansion of the set of indicators.

Introduction. The object of the study is the structures of overhead power lines (OPL), including their foundations; the subject is the actual performance of these structures (APS) at the various stages of the OPL life cycle (LC) (construction, operation and reconstruction), as a linear structure, which determines the practical significance of this paper. The aim is determined by the need to ensure the required regulatory reliability of OPL operation. The objectives of the study are to investigate the factors affecting the actual performance of OPL at the various stages of their life cycle.

Materials and methods. The actual operation of overhead line structures, as a set of real deviations of the characteristics of the elements from the standard values, is defined in the form of specific factors. The factor of emergency damage to structures, including the collapse of poles, is also included in the actual operation of structures. After repair or reconstruction, such as the replacement of damaged and collapsed poles or the replacement of old wires with new innovative wires, the operation continues as part of the life cycle.

Results. This is a real example of the successful reconstruction of a 220 kV overhead line, where the wires were replaced with new innovative wires with a gap, which allow the current-carrying part to move relative to the supporting core under high-temperature deformations. This reconstruction is possible due to the increased strength and reduced diameter of the new wire with a compact cross-section. This allowed the new innovative wires and lightning rods to be hung on old poles with reinforced foundations, significantly reducing the cost of the overhead line reconstruction.

Conclusions. This approach allowed the use of old poles for suspending new wires and a lightning protection cable. As a result, the capacity of the 220 kV overhead line increased by 60 % or more. The life cycle is represented by a new graphical model, the “life curve”, which shows the change in the failure rate ω over time τ. The curve consists of three main stages: break-in, normal operation, and wear. This graph is proposed to describe the process of subsequent reconstruction as the fourth main stage, with an extended time axis as part of the new life cycle of the overhead line.

Introduction. The problem of increasing the bearing capacity and stiffness of wooden bending elements is considered. The relevance of the work is due to the need to develop effective reinforcement methods that take into account the anisotropy of wood and the compliance of joints. The aim of the study is to improve the design of strengthening wooden beams using metal toothed plates (MTP) as external reinforcement and to develop a methodology for their calculation, taking into account the joint work of the elements.

Materials and methods. Based on the theory of composite rods by A.R. Rzhanitsyn, a method for calculating beams reinforced with MTP on a part of the span was developed. The compliance of the connections at the “beam – plate” interface was taken into account. A numerical analysis was carried out to assess the influence of the MTP type (GNA-20 and T-150), the length of the reinforced section and the value of the preliminary stress on the stress-strain state of the structure.

Results. It was found that strengthening the stretched zone of the beam with MTP can reduce normal tensile stresses by 12.3–59.6 %, and compressive stresses by 6.2–30 %, depending on the type of plate and the level of prestress. The maximum beam deflection is reduced by 1.7–27.5 %. The greatest efficiency was achieved when using GNA-20 plates with prestressing

Conclusions. A new reinforcement design and its calculation methodology are proposed. The effectiveness of using MTP to increase the strength and stiffness of wooden beams is proved. The use of GNA-20 type plates and the development of new types of MTP with improved characteristics for more complete inclusion in the work of the structure are recommended.

Introduction. This paper provides a literature review on methods for mathematically modelling steady-state and transient temperature fields in building envelopes. It is demonstrated that the thermal state of the envelope affects the energy conservation and energy efficiency of a building. It is noted that the development of temperature calculation methods is particularly relevant given the emergence of new design solutions and thermal insulation materials, such as the use of phase-change materials, the development of zero-energy buildings, and the consideration of green building.

Materials and methods. The literature review was written using both Russian and international sources. Russian papers from the Higher Attestation Commission (HAC) list and dissertations by candidates of technical sciences (PhD) were used. International sources indexed in international databases (Scopus and Web of Science) were also included.

Results. The paper describes the work of A.V. Kolesnikova, which considers a physical and mathematical model for describing non-stationary two-dimensional heat transfer in a heterogeneous fragment. The paper of L.A. Puldas is presented, examining a multifactor thermophysical model that takes into account the multi-layered nature of structures, the non-stationarity of processes, and the presence of moisture and gaseous media. The approach of T.A. Miroshnichenko, which solves the problem of the influence of a cylindrical connector on the thermal state of a three-layer enclosing structure in a cylindrical coordinate system, is considered. The mathematical model and software of N.S. Kotlyarova, allowing one to determine the three-dimensional temperature field and additional heat losses, are studied.

Conclusions. The optimal way to determine the temperature field of a building’s enclosing structure is to use a nonlinear two-dimensional or three-dimensional transient heat equation. For complex object geometry, it is possible to divide the spatiotemporal domain into a number of subdomains with their own boundary conditions. For a combined problem, it is possible to supplement the heat equation with other equations, such as the equations for the transport of water vapor, air, water, and ice.

Introduction. Capital repair of buildings is a comprehensive process that encompasses a wide range of building maintenance and construction processes. To achieve maximum efficiency, it is crucial to properly plan and manage resources, taking into account the specifics of objects, conditions, and characteristics of work performed. It is necessary to study and implement methods for combining operations that allow reducing the duration of capital repairs and lowering costs in construction and maintenance production.

Materials and methods. In this research, modern approaches to designing organizational and technological models for capital repair production were utilized. Algorithms for calculating parameters such as resource consumption intensity, task execution duration, and interprocess connection conditions were developed. Special attention was given to methodologies for assessing organizational downtimes and modules enabling efficient distribution of labour and material resources.

Results. The proposed methodologies enable optimization of capital repair processes through rational allocation of resources and overlapping of works. The use of combined flows for roofing, facade renovation, and engineering systems installation in multi-apartment residential buildings demonstrated significant reduction in total repair time without compromising the quality of executed works. Developed algorithms provide computational justification for selecting an optimal method of performing tasks.

Conclusions. The conducted research confirmed the significance of variability in overlapping works during the capital repair of buildings. Proposed algorithms and techniques make it possible to significantly reduce both the time required for completion and the cost of the works.

Introduction. A diagram of a statically determinate truss with parallel chords and an algorithm for deriving an analytical dependence of the magnitude of the structure deflection under the action of a uniformly distributed nodal load and the first frequency of natural oscillations on the number of panels are proposed.

Materials and methods. The material of the truss rods is elastic, the hinges are ideal, the load is nodal. The truss is externally statically indeterminate. All calculations of forces in symbolic form and transformations are performed in the computer mathematics system. The Maxwell – Mohr formula is used to calculate the deflection. The formula for the first frequency is derived based on a version of the approximate Dunkerley method under the assumption that the truss mass is uniformly distributed over its nodes. The nodes perform vertical oscillations. To calculate the coefficients in the formulas for the dependence of deflection and frequency, the induction method is used with respect to the number of panels. The solution of the obtained recurrent equations is performed in the Maple computer mathematics system.

Results. The coefficients of the formula for calculating the deflection have the form of polynomials with respect to the number of panels of a degree not higher than fourth. It was found that for a certain number of panels the truss allows kinematic variability. An example of a kinematically consistent distribution of virtual velocities of truss nodes is given. The method used to estimate the oscillation frequency showed good accuracy in comparison with the numerical method, which takes into account all degrees of freedom of the adopted truss model. The calculation was performed for kinematically admissible numbers of panels. The general term of the sequence of such numbers is given.

Conclusions. The methods and algorithm used to estimate deformations and natural frequency have proven their efficiency and can be applied to similar calculations of regular structures. The found cases of kinematic variability indicate the need for kinematic verification of the rod structures used in practice.

Introduction. The regularities of the propagation of harmonic longitudinal waves in discretely inhomogeneous linearly elastic rods are investigated. The relevance of the study is due to the problem of controlled transfer and localization of mechanical energy in engineering systems. The aim of the work is to develop a general analytical solution for the wave field in semi-infinite discretely inhomogeneous rods consisting of an arbitrary number of layers, as well as to show that the choice of the sequence of layers, their thicknesses, and the contrasts of mechanical parameters (Young’s modulus, density, and acoustic impedance) makes it possible to control the amplitude-frequency characteristics and to create zones of amplification and attenuation of vibrations in prescribed frequency ranges.

Materials and methods. A general analytical solution is proposed for rods composed of a finite number of layers with piecewise constant parameters. In each layer, the field is represented as a superposition of counter-propagating traveling waves, and at the interfaces the continuity conditions for displacements and normal stresses are satisfied. This leads to a matrix description (the transfer, or impedance, matrix method), which makes it possible to compute complex amplitudes in the layers, obtain reflection/transmission coefficients for a given excitation frequency ω, and construct amplitude-frequency characteristics at an arbitrary point of the rod. A procedure is presented for numerical finite element modelling of discretely inhomogeneous rod models in the ANSYS Mechanical APDL software package.

Results. It is shown that discrete material inhomogeneity makes it possible to purposefully shape the amplitude–frequency characteristics and control wave processes by creating zones of amplification or attenuation of vibrations. Using a three-layer rod as an example, the dependences of vibration amplitudes on material parameters (different wave propagation velocities in the medium) and on the frequency of external excitation are presented. Numerical verification against the analytical solution has been carried out, confirming the correctness of the modelling procedure.

Conclusions. The obtained results open up prospects for practical applications in solving engineering problems, including the design of seismic barriers, waveguides, and filters with prescribed dynamic properties that increase the resistance of structures to vibrational and seismic action.

Introduction. The problem of reducing thermal energy consumption and increasing the energy efficiency of heating systems in the residential sector in order to increase their life cycle is considered. The development of new heating device designs is an urgent priority. The aim of this study is to conduct a computational experiment to determine the hydrodynamic characteristics of simulated tubular radiators of various types, including designs featuring enhanced coolant turbulence.

Materials and methods. An analysis of relevant scientific literature devoted to improving the efficiency of heating systems was carried out.  The modelling of the coolant flow process was performed using the SOLIDWORKS software package.

Results. New designs of heating devices were developed that enable a reduction in heat energy consumption and an increase in the overall energy efficiency of heating systems. The influence of structural elements on coolant flow was investigated. It was found that maximum turbulence values and heat exchange efficiency are achieved by using spiral inserts in radiators.

Conclusions. Practical experiments have confirmed an increase in the efficiency of heating devices with spiral inserts by approximately 3  %, which leads to a reduction in energy consumption and operating costs. Improved equipment characteristics reduce the load on utility networks, extending their service life and reducing the need for frequent maintenance.

Introduction. Long-term operation of concrete products and structures under conditions of elevated temperature and humidity leads to deterioration of the physical and mechanical properties of concrete, which is caused by changes in the structure and phase composition of the cement matrix. In this regard, the study of the role of fine aggregates in the processes of cement matrix destruction under water-thermal exposure is of particular interest.

Materials and methods. Materials used for research: Portland cement CEM I 42.5N manufactured by “Oskolcement” CJSC; industrial screening of crushed quartzite sandstone by Lebedinsky Mining and Processing Plant; fine aggregate from crushed quartzite sandstone and granite in laboratory conditions. The compressive and bending strength of the specimens was determined using a hydraulic press PGM-100MG4. The microstructure was studied using a Tescan Mira 3 SEM. An STA 449 F1 Jupiter NETZSCH synchronous thermal analyzer was used to analyze the hydration products. Ultrasonic testing was performed using a Pulsar 2.2 device.

Results. It was established that concrete specimens made of quartzite sandstone exhibit a higher thermal and moisture resistance index compared to specimens made of granite aggregate. This is due to the higher absorption of lime by quartzite sandstone, which leads to the formation of thermodynamically stable compounds under conditions of high humidity and temperature. The continuous increase in the speed of the ultrasonic signal in the thermal and moisture-cured concrete specimens with the studied aggregates indicates a slowdown in the destructive processes caused by the recrystallization of hydrate phases. At the same time, due to the interaction of aggregate minerals with hydrated phases, the adhesion to the cement matrix and the strength characteristics of concrete increase.

Conclusions. Comprehensive studies showed that the most stable structures in thermo-humidity conditions are created in fine-grained concretes based on quartzite sandstone. The results obtained indicate the need for careful selection of aggregates, taking into account their ability to form thermostable hydrate phases.

Introduction. This paper discusses the application of artificial intelligence (AI) technologies in students’ final qualification projects (FQP) to solve problems in the construction industry. The tasks solved by students in 2023–2025 across three educational programmes using AI methods are analyzed. The aim of the analysis is to assess the level of AI implementation in students’ final qualification projects.

Materials and methods. The prerequisites for using AI to solve problems are described, criteria for assessing the progress of AI implementation are defined, AI technologies used in problem-solving are identified, and levels of AI technology implementation are established.

Results. The results of the analysis are presented in a clear and accessible format. It is noted that works involving the development and testing of automated systems using AI are of particular interest. The topics of such works are listed.

Conclusions. The most sought-after and accessible AI technologies are machine learning and computer vision, whilst the largest number of problem-solving applications using AI correspond to the construction phase. The task of preparing relevant topics for final-year projects for the automated solution of construction problems using AI has been set. Research prospects have been identified: the development of AI models, methods and technologies for application in the construction industry.