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The paper discusses the main aspects of implementing BIM technologies in the management of multi-apartment buildings. It highlights the features of implementing the system, including the stages of creating a digital model of the building, requirements for personnel, and specific skills. The advantages and opportunities that arise in the management process of multi-apartment buildings with information modeling technologies are noted. Specifically, it simplifies processes such as document storage and transmission, organization of building operations, current repairs of buildings and structures, and more. The prospects for the implementation of information technologies in the housing and utilities sector in the Russian Federation are already outlined: by 2023, developers are required to use these technologies when planning and constructing multi-apartment buildings. The government is implementing a series of systemic initiatives and measures aimed at the digitalization of multi-apartment building management, supporting the development of the sector towards a service model, and ensuring comfortable living conditions for citizens. To support these initiatives, it is necessary to unify requirements for services, standards for data collection, transmission, processing, and access, and to clarify the rules of interaction among participants, taking into account the active implementation of digital technologies in practice. The primary principle of digitalization should be economic feasibility. The implementation of digital technologies should provide real value for developers, management organizations, owners of residential and non-residential premises, and authorities. To achieve digitalization results, it is necessary to create conditions that stimulate the efficiency of interaction between subjects involved in the digitalization of multi-apartment building management. In particular, it is required to establish requirements for the implementation of information technologies at the legislative level.

The study investigates a thermosetting polymer filled with montmorillonite. Montmorillonite is a naturally occurring layered mineral with particle sizes ranging from 8 to 12 µm. The thermosetting polymer was DER-330 epoxy resin and FCH-S hardener. Rheological and physical-mechanical studies of the properties of epoxy resin modified with montmorillonite were carried out. Viscosity versus shear rate is shown for uncured pure epoxy resin and resin modified with montmorillonite particles at room temperature. At low shear rates, a significant effect of montmorillonite on the properties of the composite is observed. The low shear rate further allowed epoxy molecules to leak between the layers of montmorillonite platelets, causing swelling and increasing the distance between them. As the shear rate increased from 8 to 20 s-1, the percolation time of montmorillonite decreased, which affected the decrease in viscosity. When the shear rate increases above 20 s-1, no significant changes in viscosity occur; for both samples a monotonic line is observed on the graph. The addition of montmorillonite to epoxy resin changes the chemical composition of the composite, which leads to changes in rheological and physical-mechanical properties. The addition of montmorillonite retards gelation, which can affect processability, cure time, and final properties of the composite. Morphological studies were carried out to determine the degree of dispersion of montmorillonite particles in the polymer composite using a transmission electron microscope. The uneven distribution of montmorillonite particles predominated in all samples. Apparently this is due to the curing conditions of the polymer composite and insufficient dispersion time. Physical and mechanical studies were carried out on samples made of a composite with montmorillonite in comparison with samples from pure epoxy resin. The flexural strength of samples made from the resulting composite is comparable to the strength of samples made from pure epoxy resin. In turn, the viscosity increased by 170%.

Рассмотрены нормы по расчету сжатых сталежелезобетонных стоек, а также экспериментально-теоретические исследования других авторов. Выполнено экспериментальное исследование работы сжатых стоек с малым эксцентриситетом на диапазоне гибкостей от 6 до 20. Выполнено численное моделирование различных вариантов конструкций: с бетонами от В30 (С25/30) до В100 (С90/105), с сердечником в виде двутавра, с сердечником в виде квадрата. Полученные данные экспериментов и расчетов сопоставлены с теоретическими кривыми коэффициента продольного изгиба. Установлено, что кривые коэффициента в СП 266.1325800 и Eurocode 4 имеют не корректную форму и не отражают действительной работы сталежелезобетонных сжатых элементов. Использование кривой СП 266.1325800, основанной на кривой для железобетонных конструкций, а также кривых Eurocode 4, которые приняты как для стальных сечений (по Eurocode 3) – не дает нормального запаса конструкций и не обеспечивает надежность. Оба норматива игнорируют различный характер работы бетонов обычной и высокой прочности. В результате исследований установлено, что класс прочности бетона на сжатие влияет на устойчивость стержней с гибкостью от 6 до 10, при этом влияния формы поперечного сечения сердечника (вида жесткого армирования) практически нет. Для гибкостей от 10 до 20 может быть принята единая для всех бетонов кривая коэффициента. Разработаны кривые коэффициента для расчета сжатых элементов при малых эксцентриситетах и кратковременном действии нагрузок; предложена формула расчета несущей способности сжатых стоек.

In the realm of geotechnical engineering, deep excavation projects face intricate challenges, especially concerning the stability of barrette walls, which are highly susceptible to deformation and stress at their joints. This study focuses on evaluating the deformation and force behavior of barrette wall joints at the position of greatest deformation. The Finite Element Method (FEM) is utilized to simulate the behavior of these structures under various load conditions. The Analysis of Variance (ANOVA) method is employed to statistically analyze the FEM data, assessing the impact of different factors on deformation and force distributions within the barrette wall joints. The specific objective of this study is to determine the statistical significance of the observed deformations and understand the influence of construction stages on joint integrity. This methodological synergy enhances the predictability of engineering assessments and ensures that design and construction decisions are grounded in solid empirical evidence. The study's findings emphasize the importance of precise monitoring and advanced predictive techniques to mitigate potential risks associated with deep excavations, particularly at critical joint locations. The results indicate that the deformation patterns are primarily influenced by the geometrical setup of the walls and the mechanical properties of the soils. The greatest deformations were typically observed where the wall joints experienced the highest bending moments and shear forces, conditions exacerbated by unfavorable soil mechanics and hydrostatic pressures. The clear and consistent increase in total displacement highlights the progressive destabilization of the wall as the excavation depth increases. By integrating ANOVA with FEM, this study contributes to enhancing safety and efficiency in deep excavation projects by ensuring that decisions are grounded in empirical evidence.

Modular blocks are widely used in industrial and civil engineering both as stand-alone structures and combined into block-modular buildings. Modular block consists of the load bearing frame, wall fencing, roof and floor decking. The modular block, with wall fencing made of corrugated sheet continuously welded to the beams, is a spatial system, with beams and corrugated webs working together. The steel modular block for the gas pumping unit on a gas turbine power plant is considered in the paper. Assessment of the corrugated web thickness effect on the load bearing capacity of the block is performed. Numerical investigation of stress-strain state of the blocks with different thickness of corrugated web is carried out by the finite element method. The values of the ultimate destructive load on the blocks with different thickness of the corrugated web are determined. The values of the allowable load on the block and the criteria for its limitation have been established depending on the stress-strain state of the block and the causes of destruction. For comparison, a calculation was made of a block with walls made of sandwich panels that are not included in the work of the frame. It is determined that ultimate load on the block with corrugated webs is 1,5-6 times greater than on the block with wall sandwich panels.

At a single action on a concrete and reinforced concrete structure short-term dynamic load, the value of which may exceed the value of the static load-bearing capacity of the structure, it was observed that failure will occur not immediately, but after a certain time (delayed failure time td). If the dynamic load action is stopped before the moment td, the structure will not collapse. Therefore, the accurate determination of the delayed failure time of concrete is an important and relevant problem. To solve this problem, the paper presents a visco-elastic-plastic model to describe the stress-strain state of concrete under dynamic loading. This model consists of 2 elements: a nonlinear spring A and a piston B connected in parallel. Element A describes the nonlinear elastic-plastic properties of concrete, and element B takes into account the high-strain-rate effect of concrete. Under the action of sudden dynamic loads with an intensity greater than the static bearing capacity of the concrete, piston B helps to inhibit the development of deformations initiated in element A. Based on the proposed model, the delayed failure time is defined by the time interval required for the deformation of concrete to reach its ultimate value. The main factors affecting the deformation and failure of concrete such as concrete compressive strength, overload level, and viscosity are also investigated. Specifically, as follows: The higher the static compressive strength of concrete, the lower the delayed failure time. When a dynamic force of greater intensity is applied compared to the bearing capacity of the concrete, the faster the specimen will destroy. In addition, the viscosity coefficient significantly reduces the strain rate of concrete and the corresponding delayed failure time increases as the viscosity increases.

Solution of the problem of two-dimensional theory of elasticity with the use of discrete-continual finite el-ement method in the presence of crack is under consideration in the distinctive paper. The original operational continual and discrete-continual formulations of the problem are given, an example of analysis are presented.

The article presents a probabilistic approach to the design of flexural elements made of cross-laminated timber (CLT) as one of the promising materials for sustainable construction. The variability of the elasticity modulus and the ultimate strength of the timber layers effects on the structural safety. Such uncertainty can be modeled by using probabilistic and statistical methods. Information is presented on tests of a three-layer CLT panel during bending, and statistical parameters are given for wooden control samples of the CLT panel layers. The implementation of the presented approach makes it possible to obtain an estimate of the reliability index or the failure probability for the CLT structural element according to the criterion of normal cross-sections strength. With a given target level of reliability or risk value, the reliability level of the design solution of a cross-laminated structure can be quantified.

In this paper, the problem of numerical modeling of the dynamic behavior of bending beams made of the materials with a developed internal structure is considered. The simulation is performed taking into account the non-local elastic properties of the material in time. According to the principals of nonlocal mechanics, it is assumed that elastic forces in a structure depend on the entire history of its deformation, and not only on the instantaneous deformed state. The proposed dynamic deformation model is proposed as an alternative to detailed three-dimensional models. The nonlocal dynamic deformation model is integrated into the algorithm of the FEA method to make it applicable to solving applied engineering problems. The numerical implementation of the model is performed in Python. A technique for selecting the scale parameter of a non-local model based on experimental data using the least squares method and the dichotomy method has also been developed and implemented. To identify the possibility of extrapolation of the scale parameter values determined according to the developed methodology, a series of numerical experiments were conducted, on the basis of which scale parameters for beams of different lengths were obtained and the stability of the nonlocal model was evaluated.

The results of numerical investigations of the filtration regime and stability of an earth dam under reservoir drawdown are considered. The problem of unsteady filtration in a homogeneous earth dam is solved. The parameters of the filtration flow are determined: the position of the depression surface, the values and direction of filtration gradients and flow velocities. The changes in the maximum filtration gradients and the probability of filtration deformations are analyzed. Calculations are made to assess the stability of the upstream slope during the stages of reservoir drawdown with different velocities. It is shown that a dam with a large stability margin when the reservoir is full may lose it and be destroyed in the process of drawdown. Conclusions are drawn about the necessary measures to ensure reliability and safety during operation of the structure.

В настоящее время конструкции из современных алюминиевых сплавов находят все боль-шее применение практически во всех сферах промышленного и строительного производства, что является следствием уникальных физико-механических свойств алюминиевых сплавов, позволяющих создавать эффективные по весовым, прочностным и эстетическим параметрам конструкции самого разнообразного назначения, обладающие при этом повышенной коррозионной стойкостью по сравнению со стальными конструкциями. Однако изготовление конструкций из алюминиевых сплавов является более сложным технологическим процессом из-за необходимости применять специальные методы сварки алюминия по сравнению с традиционными методами сварки стальных конструкций. Наиболее распространенные в настоящее время аргонодуговой метод и метод сварки трением с перемешиванием конструкций из алюминиевых сплавов более сложно реализуются в полевых условиях при монтаже и сборке элементов кон-струкций на строительной площадке, и требуют квалифицированного персонала. По этой причине является актуальным использование иных методов сварки элементов алюминиевых конструкций, не требующих сложного оборудования и квалифицированного персонала аналогично классической электросварке.

A composite hydraulic structure is used to solve the problems of sediment and floating materials, respectively. A pier (obstacle) is used at the downstream of the composite hydraulic structure to increase water depth, decrease flow velocity, and dissipate the flow energy. The paper deals with the effect of single pier and double piers on the hydraulic characteristics of the composite structure. Circular and square shapes are adopted in the study with different spacing measured from the downstream of the composite structure. The experiments reveal how the level of the hydraulic characteristics is changed due to the existence of the pier/piers as compared to without the existence of the pier/piers. The statistical data which is collected from the experiments shows the alteration in the average downstream water depth, discharge coefficient, Reynolds number, upstream Froude number and downstream Froude number regardless of pier shape and spacing. The alteration happens owing to a change in the separation zone of water flow along the pier circumference. Nonlinear water surface profile is appeared when the pier is located at the downstream, while linear water surface profile is appeared clearly when the downstream without pier. Also the interference between overflow velocity and underflow velocity will be reflected in the hydraulic characteristics.

This paper presents a contribution to the study of the stability of steel trusses. The paper proposes an analytical model for the determination of the buckling length coefficient of the truss N by the lateral torsional buckling approach. The model is derived by considering the equilibrium of the truss under the action of the applied loads and the buckling load. The buckling load is determined by considering the lateral buckling of the equivalent beam and the interaction between the members. The model is validated by comparing the predicted buckling loads with the experimental results of several steel trusses. The results show that the model can predict the buckling loads with good accuracy. The proposed model is a valuable tool for the design of steel trusses. The model can be used to determine the buckling length coefficient of the truss and to ensure that the truss is safe and reliable.

В последние десятилетия наблюдается повышенный интерес к изучению напряженно-деформированного состояния трубобетонных конструкций – композитных элементов, состоящих из стальной трубы-оболочки и бетонного сердечника, находящегося в состоянии трехосного сжатия. В таком сочетании сталь и бетон позволяют достичь лучших прочностных и деформативных характеристик, чем при их раздельной работе, что позволяет проектировать безопасные и экономичные конструкции. В настоящей статье приводятся результаты экспериментального исследования процесса деформирования изгибаемых трубобетонных элементов малогабаритных круглых сечений. Показано, что при трехточечном поперечном изгибе трубобетонной балки помимо прогиба за счет искривления оси стержня, существенное влияние на вертикальные перемещению оказывают деформации локального смятия в местах приложения сосредоточенных нагрузок. Проводится оценка возможности применения классической теории изгиба полой стальной балки по модели Бернулли. Сопоставляются результаты испытаний и диаграммы деформирования полых стальных труб (аналитические и экспериментальные данные) и сталежелезобетонных балок труб, заполненных бетоном. Произведена качественная и количественная оценка вклада наличия бетонного сердечника на несущую способность и деформативность (в т.ч. местное смятие) элемента. Наличие бетонного сердечника в композитном стержне дает существенное утяжеление конструкции, однако в случае внецентренного сжатия несущих вертикальных элементов многоэтажных зданий эффективность применения трубобетонных элементов весьма эффективно.

The study provides experimental and theoretical investigations of stress relaxation in concrete under preset constant deformation of specimens and proposes an approach to the mathematical determination of stress relaxation in concrete. In addition to mathematical modeling, parallel long-term tests were performed on concrete specimens of the same class under four different regimes: determination of concrete creep in compression (concrete prism specimens in spring installations) according to GOST 24544; determination of concrete relaxation in compression (concrete prism specimens in special installations, determination of concrete creep in bending (concrete specimens-beams in rack-type installations working in bending and loaded with gravity load) according to GOST 24544; determination of concrete relaxation in bending (concrete specimen beams, with applied initial deformation in the middle of the span Determination of stress drop was performed using electronic dynamometers built between the specimen and the point of load application. A new concept, "relaxation measure Rm", was proposed. This value is similar in meaning to the creep measure and characterizes the degree of stress reduction in time due to relaxation when loaded with a unit relative strain. The introduction of relaxation measure allows to simplify the relaxation equation and significantly simplifies its solution. According to the results of calculation by the proposed computational algorithms for determining the relaxation measure in comparison with the experimental data, a satisfactory convergence of the results is obtained Qualitative conclusions about the applicability of the methodology of SP 63.13330 for reducing the modulus of elasticity of concrete in creep and relaxation.

The design of optimal seismic protection systems on bearings with hysteresis behavior leads to a conditional multidimensional global optimization problem with a nonlinear and non-differentiable objective function. In this paper, bearings with bilinear characteristic with hysteresis are considered, i.e. for each nonlinear bearing there are four parameters to optimize: ultimate elastic displacement and stiffness for the elastic mode and ultimate displacement and stiff-ness for the inelastic mode. We study the seismic response of an elastic beam on four nonlinear bearings under vertical seismic ground motion. The perturbation functional as an integral of the quadratic form of the state vector with a weight matrix formed from the stiffness and inertia matrices of the system on equivalent elastic supports is considered as the objective function. Minimization of the functional means the minimum of the total energy of the system on equivalent elastic bearings. Genetic algorithm is used to solve the optimization problem.

Low specific weight and high mechanical strength (especially at elevated temperatures) of titanium and its alloys make them very valuable aviation materials. In the field of aircraft construction and aircraft engine production, titanium is increasingly replacing aluminum and stainless steel. At present, aircraft developers are restructuring the whole material science concept of aircraft construction, actively involving and using various types of composite materials based on titanium alloys. Combined with the properties of titanium, FML composites based on titanium have greater stiffness, impact resistance, heat resistance, and corrosion resistance especially compared to similar aluminum-based materials. The paper investigates the dynamic characteristics of hybrid titanium-polymer composite materials (TPCM) based on titanium alloy BT-23 and fiberglass with a brief presentation of the main characteristics of prepregs. The process of manufacturing specimens for testing including heat treatment, ply laying scheme and reinforcement scheme in two variants is described. The results of experimental studies of natural frequencies and damping coefficient by the method of free damped oscillations in free oscillations of TPCM plates are presented. The tests are carried out on a specially designed unit with a triangulation sensor in the variant of vertical loading. Two identical specimens with different overall dimensions are tested.Each specimen was tested with a different amplitude. Five tests were conducted for each amplitude. The physical constants of the specimens were pre-determined in static tests. The natural frequencies and damping coefficients for the titanium-polymer composite specimens were found.

The results of the analysis and generalization of research on the problem of using man-made industrial waste for the production of composite slag-alkali binders and concretes based on them are presented. The disposal of industrial man-made waste and their use in the production of composite binders are issues of global importance. Therefore, much attention is paid to this issue in the industrialized countries of the world.The influence of waste products from the enrichment of polymetallic ores – carbonate-barium tailings on the performance properties (strength, water absorption, density, etc.) of composite slag-alkali binders and concretes based on them has been studied. Various methods of introducing modifying additives into the composition of composite slag-alkali binders and concretes based on them have been investigated. The optimal amount of introduction of modifying additives into the composition of composite slag–alkali binders - waste of carbonate-barium tailings and an efficiency indicator for the effect on the activity of concrete, depending on the type of alkaline component and hardening conditions, has been established. The methods of conducting experimental work to determine the operational properties of slag-alkali binders and concretes based on them are presented.

A discrete-continuous approach was applied to the moisture transfer equation, which made it possible to obtain an analytical solution for the moisture potential. The new method was applied to study the unsteady-state moisture regime of the facade heat-insulating composite system with expanded polystyrene insulation and aerated concrete base. It was found that the mass moisture content of building materials achieved in the walls during the period of operation is lower than the mass moisture content used in construction regulations, which makes it possible to increase the accuracy of calculating the transmission heat losses of the building. Calculations of heat losses of a two-storey building in the climatic conditions of Moscow (Russia) showed a decrease in the heating system load by 5 %, and the reduction in heat losses for specific premises of the building ranged from 3.6 to 7 %.

High air permeability and the presence of thermal bridges at the junctions of wooden frame wall panels have a significant impact on the thermal balance of the building and its operational characteristics. The importance of improving the energy efficiency of nodal interfaces of panels with a wooden frame is undeniable. To date, there is no single generally accepted method for calculating heat losses through nodal interfaces of panels with a wooden frame. Based on the analysis carried out, it is necessary to carry out calculations and measurements that allow creating this calculation methodology. To carry out numerical studies, a list of characteristics and parameters affecting their conduct is formulated: the influence of the thickness of a li-ear-discrete inclusion on the heat-protective properties of the panel docking unit; the thermal conductivity characteristics of the material used to fill linear-discrete inclusions affecting the heat flux density of the node interface; consideration of the influence of the outdoor temperature of air depending on different climatic zones on the density of heat flow. The dependences of the heat flux density on the "inner" surface of the experimental samples on the thermal conductivity coefficient of the material of the insulating insert, the width of the insulating insert and the outside air temperature were revealed and the nature of the temperature distribution on the "inner" surface of the prototypes was established. By calculating two-dimensional temperature fields in the cross section of the node, isofields of temperature distribution inside the structure, isofields of heat flux density and its direction, lines of temperature distribution and heat flux density along the inner and outer surfaces are obtained. It was found that the heat flux density in the ribs with heat-insulating inclusions is lower in comparison with solid wood parts by an amount from 13% to 52%.

The method of replacing the existing distributed load with an equivalent load in the form of concentrated forces applied at the nodes is often used in frame stability problems. This replacement of the initial flexural equilibrium with an unbended tension-compression equilibrium introduces certain errors in the calculated values ​​of critical loads. These errors can be of different signs (ie, the calculated "pseudo-bifurcation" critical force can be either greater than the actual one or less than it). The paper demonstrates the errors of such a load change on the example of frame stability problems.

In this paper, the solution of a joint temperature filtration problem is considered in relation to a soil dam in a cryolithozone. The dam is designed according to one of the principles adopted for the design and construction of structures in such climatic conditions. A description of the methodology used is given. Using the PLAXIS software package, a numerical solution to the problem was obtained, taking into account the phased construction of the structure, repair and reconstruction of the structure caused by the occurrence of an emergency situation after rapid filling of the reservoir. The obtained results of solving the temperature filtration problem revealed problems with ensuring the "frozen" regime of the structure and the need to take additional measures for this.

In the realm of urban construction employing excavation techniques, safeguarding existing underground structures from detrimental consequences arising from surface construction operations poses a formidable challenge. The reduction of loads due to excavation activities can induce unintended responses, potentially jeopardizing subterranean infrastructure, particularly high-safety-demanding structures like Tunnel Boring Machine (TBM) tunnels. This article introduces an uncomplicated method for ascertaining the axial displacement of TBM tunnels amidst concurrent surface excavation activities. Primarily, the approach entails the identification of stress variations encountered during soil excavation at the tunnel face. Subsequently, employing the solutions derived for the determination of tunnel deformation subjected to concentrated loads, the deformation incurred by the tunnel due to alterations in excavation-induced stress is quantified. The analytical outcomes are meticulously juxtaposed against results generated from a three-dimensional computational model. The comparative analysis demonstrates that the displacement values and axial deviations calculated using the proposed analytical method exhibit only marginal disparities of 4,3% and 1%, respectively, when compared to those obtained through finite element analysis. This study underscores the efficient predictive capabilities of the analytical method in assessing tunnel deformations, enabling a preliminary estimation of critical parameters associated with the excavation pit. These findings have significant implications for mitigating adverse impacts on existing subterranean infrastructure in densely populated urban areas.

Energy methods for calculating structures, which have become popular for a century, are based on the Lagrange principle and have the meaning of equality of work of external forces and internal forces. Having proved their effectiveness in the overwhelming majority of problems of structural mechanics, they became the dominant approach in formulating the problems of studying solid deformable systems and gave rise to the main methodology for solving problems. As a result, a situation has arisen that the internal potential energy of a deformed body remains insufficiently studied. The paper develops an approach to the study of the symmetric structure at critical levels of strain energy. The criterion of critical levels of strain energy, based on the concepts of "self-stress" ("self-balance") of a deformable body. Limiting values of the structure strain energy may get by varying the reactions and deflections in the nodal points. The extreme values of forces and displacements of the rods are calculated in matrix form from the values of nodal reactions (displacements). Methodology for studying the energy properties of a system is shown on the examples of the study of symmetric rod systems without involving the concept of external forces. The technique is based on matrix methods of structural mechanics and the mathematical apparatus of eigenvalue problems. The comparison of structural design and structural analysis solution of structural mechanics tasks by traditional methods and with the proposed methodology is carried out.

Shallow shells with variable curvature, prestressing contour and fixed above by horizontal reinforcing of two opposite contour elements are considered in the given article. These two offered ways practically produces non-moment state and increase loading capacity of the shallow shells several times. Method of definition of loading capacity of the shallow shells with a flat rectangular contour was worked out, and it's aim consists of that initial moment state before loss of loading capacity is described by nonlinear differential equations of the theory of the shallow shells. And then accentuating the main part of the solution of equations we receive the linear system of homogeneous differential equations with variable coefficients. The solution of the linearizated equations enables to define the forms of losing of loading capacity of shallow shells.

Structural Health Monitoring (SHM) is a crucial discipline geared towards detecting damage in engineering structures early, aiming to prevent failures and facilitate condition-based maintenance. Traditional SHM methodologies, relying on visual inspections, analytical models, and signal processing, exhibit inherent limitations. The advent of machine learning has introduced data-driven solutions to automate various aspects of SHM, including damage detection, localization, classification, and prognosis. This paper provides a comprehensive review of recent studies exploring supervised, unsupervised, and deep learning techniques in vibration-based, image-based, and multi-sensor SHM. Support vector machines, neural networks, deep convolutional neural networks, and other advanced algorithms have demonstrated exceptional performance in assessing damage using real-world structural datasets. Despite these successes, practical challenges persist, particularly in addressing variability and deploying machine learning models effectively on full-scale structures. Overcoming these challenges necessitates a more integrated, cross-disciplinary approach, merging mechanical engineering fundamentals with machine learning expertise. This synergy can pave the way for robust field implementation and further enhance the reliability of SHM systems. The transformative potential of machine learning in SHM cannot be understated. Beyond merely shifting from time-based maintenance to condition-based strategies, machine learning can automate and continuously evaluate structural integrity, ensuring the longevity of engineering structures. As we delve deeper into the intersection of mechanical engineering and machine learning, the prospect of a future where SHM seamlessly integrates with advanced technologies becomes increasingly tangible.

Numerical hydrodynamic modeling of the flow of water and sediment through the fish-spawning pass of the Bagaevsky hydroelectric complex on the river Don is considered. The calculations use two-dimensional shallow water and sediment transport equations by the STREAM 2D CUDA software complex. Recommendations are made to change the longitudinal profile of the bottom and the configuration of the inlet section, as well as to increase the coefficient of roughness of the bottom and sides of the channel to ensure fish protection requirements.

A methodology for constructing variational formulations and solving geometrically nonlinear mixed problems by the finite element method is considered using the example of equilibrium of a flexible tensile thread. The results of solving the model problem are presented.

Key aspects of developing effective systems for the external reinforcement of building structures, made of composite polymer materials containing carbon fibers and no-bake polymer binders, ensuring shape formation in the temperature range of 15 - 40 °С no more than 24 hours, characterized by operability in the temperature range from minus 45 ° C to plus 60 ° C.. PCM-based SVA has a number of advantages compared to clips and metal profiles traditionally used for repairing building structures: the load-bearing capacity of the rods increases, the cost of the strengthening of load-bearing structures is reduced, and the seismic resistance of engineering structures is increased. In relation to composite SVA building structures, the following types of construction chemicals are used: primer, putty, adhesive, protective coating. The production of unidirectional tapes was carried out on a Dornier double rapier loom, modernized for processing carbon fibers. The results of experimental studies of the developed polymer binders and carbon reinforcing fillers are presented. It is shown that the developed materials can be successfully used to strengthen and repair engineering structures. The technological features of strengthening and repairing building structures with composite external reinforcement systems using the contact molding method and ready-made lamellas are described. Installation of composite clamps on vertical surfaces is carried out by fixing the canvas in the extreme position, followed by laying, smoothing and rolling along its length. Rolling is done from the middle to the edges. Before gluing the blanks, the lamellas are laid out on a work table (workbench) and thoroughly wiped with a rag moistened with acetone. Results of the large-scale implementation of these new materials and technologies in the construction industry are presented.

Проблема сжигания природного топлива в настоящее время является крайне важной экологической задачей. Дымовой газ, выбрасываемый в атмосферу, негативно влияет на окружающую среду. Последствия этого могут быть самыми разнообразными, от выпадения осадков, содержащих кислотные соединения, до повышения уровня легочных заболеваемостей населения. Решением проблемы сжигания топлива при выработке энергии в тепловых электростанциях может служить конструкция, называемая комбинированным высотным сооружением. Она объединяет в себе две составляющие: градирню и, непосредственно, дымовую трубу. Исследование характера течения газов в таком сооружении является чрезвычайно важной задачей, так как от процесса смешения дыма с дополнительно подаваемым воздухом в трубу зависит концентрация выброса вредных веществ в атмосферу. Данная статья посвящена численному изучению газодинамики в рассматриваемых сооружениях. Представлено обобщение метода поверхностей равных расходов для описания внутренней аэродинамики сооружения. В основе математической модели используется вязкий сжимаемый газ. Течение описывается системой уравнений Навье-Стокса, записанной в параболизованной форме, дополненной алгебраической моделью турбулентности. Численное решение проводится методом конечных разностей. Рассмотрены различные варианты геометрии конструкции и начальных условий. Отмечено благоприятное воздействие начальной закрутки потока на интенсивность смешения дымовых газов и уменьшение концентрации вредных веществ на выходе из трубы. На основе проведенных исследований разработаны рекомендации для проектирования и профилирования возводимых сооружений.

The strength properties of subsiding loess soils are considered in the mathematical modeling of their compaction by deep explosions. Soil compaction is carried out in order to eliminate their subsidence properties. Correlation and regression analyzes of the dependences of strength on the physical characteristics of loess were carried out, using the soils of the North Caucasus as an example. The correlation dependence of the specific cohesion and the angle of internal friction on the physical characteristics of the subsidence soil is established. Correlation coefficients were obtained for various indices of moisture content and loess density. The studies were carried out before and after soil compaction in this way. Both positive and negative correlations between the studied characteristics of subsiding loess soil were recorded. With an increase in moisture, a high correlation was observed with the strength characteristics of the soil before and after its compaction by deep explosions. The equations of regression of specific cohesion and the angle of internal friction on soil moisture and density are constructed. The reliability coefficients of approximation of theoretical regression equations and experimental data demonstrate high values. The regression equations of specific adhesion and the angle of internal friction on soil moisture showed that the values of strength characteristics increase with decreasing values of soil moisture. The regression dependence of the specific cohesion and the angle of internal friction on the density of subsidence loess has been studied. It has been established that an increase in the values of strength characteristics was recorded with an increase in the density of loess soil before and after its compaction by deep explosions. The constructed regression equations make it possible to predict the strength characteristics of loess at the stage of designing the bases and foundations of construction objects.

Experimental and numerical studies of the bearing capacity and deformation of T-beams with a flange made of high-strength concrete and longitudinal reinforcement of class A500C with a web made of concrete of ordinary strength were carried out on prototypes of beams and numerical models. The beams being tested are considered at different percentages of reinforcement. The calculation scheme of the beams corresponded to a four-point bend. As a result of experimental and numerical studies, the nature of the destruction of beams, their deformation and the nature of cracking are determined. Experimental and numerical relationships of relative deflections on relative bending moments are obtained. A comparative analysis of the values of the bearing capacity and the relative height of the compressed zone of the beams, obtained experimentally, numerically and according to SP 63.13330.2018, was carried out. The nature of the distribution of deformations in concrete of normal section of beams at different levels of loading is determined.

While designing high-rise buildings, it is necessary to take into account the influence of stages of their erection, this is the sequence of loading, on the change in physical-mechanical properties of soils. The calculation of deformations of subgrade is made with due regard for the change in soils properties comparing with the initial (natural) state. On the basis of the results of experimental studies, the authors substantiate the necessity for introducing the new parameter which makes it possible to characterize the mechanical condition of the soil at any stage of loading and can be used for creating calculation models. An analytical diagram of soil deformation in coordinates «σ1–ε1» for triaxial compression (where σ1 – vertical stresses (deviator), ε1 – linear deformations under the triaxial compression) is adopted as this parameter. The procedure for constructing transformed diagrams of the soil state under the long performance triaxial loading is described. The procedure obtained was approbated when calculating deformations of the foundation base of the high-rise building with due regard for the influence of staging of construction and rheological properties of soils on the change in the base rigidity and, as a result, on the redistribution of stresses among separate elements of the system “subgrade –foundation – upper part of the building.

The features of the behavior of steel-plate composite walls for static loads are considered. Based on the analysis of modern technical and regulatory documentation, the rationale for the chosen research topic is given. A review of the literature is performed, and the features of development are noted. A detailed description and features of the experimental structures under study and the materials used are presented. The features of the test are considered, and the test equipment is described. Analytical and numerical calculations of structures for eccentric compression have been performed. The description of the calculation complex and the used models of materials is presented; the description of numerical models, the features of their construction and calculation are given, the results of calculations are presented – stress distributions, deformations, features of cracking. The general types of experimental eccentric compression wall models are presented, the nature of the loss of bearing capacity of experimental structures is described, and a picture of destruction is presented. The analysis of the experimental data obtained and their comparison with analytical and numerical calculations are performed.

To date, for some elastic systems with a finite number of degrees of mass freedom, in which the directions of mass movement are parallel and lie in the same plane, methods have been developed for creating additional generalized targeted constraints and generalized targeted kinematic devices. Each generalized targeted constraint increases, and each generalized targeted kinematic device reduces the value of only one selected natural frequency to a predetermined value, without changing the remaining natural frequencies and natural modes. Earlier, for elastic systems with a finite number of degrees of mass freedom, in which the directions of mass motion are parallel, but do not lie in the same plane (for example, plates), an approach for the computing of a matrix of additional stiffness and a method for the development of computational schemes of additional generalized targeted constraints were developed. Also earlier, for such systems, an approach was proposed for the computing of a special matrix with allowance for additional inertial forces that determine a generalized targeted kinematic device. At the same time, the method of development of computational schemes of kinematic devices was not proposed. The first part of the paper was devoted to approach, that made it possible to develop computational schemes of generalized targeted kinematic devices for such systems as well. A variant of the computational scheme of constraint for the rod system with one degree of activity was considered. Some special properties of such targeted kinematic devices were revealed. The distinctive second part of the paper is devoted to corresponding samples of analysis.

The article proposes a method for processing concrete creep curves based on the nonlinear equation of V.M. Bondarenko. The experimental data of A.V. Yashin is used. The problem of finding rheological parameters and the nonlinearity function is posed as a nonlinear optimization problem. The objective function represents the sum of the squared deviations of the experimental values of the creep strain from the theoretical values for all creep curves for one concrete at different stress levels. The minimum of the objective function is found using the interior point method, the surrogate optimization method, the pattern search method, the genetic algorithm, and the particle swarm method. It has been established that the first of these methods has the greatest efficiency. The proposed approach provides high quality approximation of experimental curves at all stress levels. It is shown that for concrete the nonlinearity of creep deformations is more pronounced than the nonlinearity of instantaneous deformations, and the same function cannot be used to describe these two types of nonlinearity.

The article focuses on the possibilities of multi-optional design of repair and rehabilitation works on dilapidated pressure pipeline networks with the use of automated complexes in order to achieve minimum energy costs in water transportation with regard to the temperature factor. Two automated programs based on hydraulic and energy calculation operations are presented as digital tools. As a basic variant of reconstruction of dilapidated pipelines, the trenchless Swagelining technology was accepted. It is realized by pulling pre-compressed polymer pipes into old pipelines with their subsequent straightening. The paper presents information on regulatory and technical documentation and the application of advanced technology, installation and operation conditions, as well as comparative assessment of energy consumption after reconstruction of dilapidated sections of pipelines with polymer pipes with the possibility of minimizing energy consumption during water transportation under non-isothermal conditions of pipeline operation.

The publication relates to the problems of digitalization of building materials science. The relevance of developing a digital model of concrete for solving optimization problems of design and synthesis of its structure, clarifying methods for calculating building structures, and improving the technology of their production is shown. The evolution of information modeling of concrete is analyzed in the context of the stages of development of system-building materials science and technology. A review of the main modern methods of computer modeling of concrete structure in domestic and foreign scientific research is provided. It is noted that these methods do not take into account the complexity of the structure of concrete. In the article, concrete is presented as a conglomerate composite with a hierarchically organized structure with dimensions from 10-10 to 10-1 m. It has a minimum of 5-6 scale levels and three types of substructure design. Substructures differ in their scale, genesis and mechanics of manifestation of properties. The first type of substructure is characteristic of the macro-, meso- and micro-scale levels. It is accepted in the form of a two-component “construction” of a spatially continuous matrix and discrete inclusions deterministically and stochastically distributed in it. The second type refers to the submicro-, ultra-micro- and nanoscale levels. It is believed to be in the form of a “microscale spatial structure” of new formations of a cementing substance from consolidated individual crystalline differences. The third type corresponds to the atomic-molecular structure of new formations of the cementing substance. The characteristics of each type of substructure are given according to: the scale of the components; features of formation; mechanics of properties manifestation; design criteria; means of synthesis. An assumption is made about the specificity of modeling each of the three types of concrete substructures and their integration into a single digital model. The task is to develop an information platform for such a model. The platform should include: a theoretical knowledge base; empirical data base; database of analytical, numerical and statistical models; algorithms for designing and synthesizing structures; optimization criteria and boundary conditions; terms of reference for computer modeling of concrete.

Civil engineers are encouraged to apply novel techniques, to improve and to adapt well-known methods amid the reality of modern life. An impressive number of restoration and strengthening techniques are developed for unreinforced masonry (URM) material well-known for centuries. Masonry may need restoration and strengthening due to errors made in the course of design, construction or long-term operation of buildings and structures. Besides, masonry needs strengthening in seismic areas. Strengthening of masonry structures, subjected to dynamic impacts during military operations, was initiated after the Second World War. Construction technologies advanced considerably over the last seventy years, and today shotcrete, a widely known strengthening technique, can be applied for a good reason. This article addresses shotcrete as a method for restoring masonry damaged by explosion impacts. Results of the laboratory testing of materials and parts of structures are provided together with improved methods of analysis. The methodology for computer-aided analysis of buildings is also presented, taking into account the staged nature of work and the ability of external shotcrete to support loads. Practical restoration of buildings is addressed in the conclusions section, and conclusions are drawn there.

The article identifies the problems of the modern international nuclear energy market, analyzes domestic and foreign experience in the construction of technically complex megaprojects, studies and systematizes organizational and technical aspects of the concept of reliability and risks of technically complex industrial facilities on the example of an international project for the construction of a nuclear power plant. The purpose of the research article is to solve one of the most important tasks – to determine the total investment risk and its assessment in an inextricable relationship with the stages of the project life cycle. The article systematizes both the principles of assessing the organizational and technical reliability of the system under study, as well as the methods of types of aggregate investment risk. A proprietary multi-criteria approach to the concept of reliability is being developed using modern theoretical methods in the context of the development of nuclear power plant construction projects abroad, respectively, taking into account country and industry risks.

Axial bearing capacity is an important factor in designing of foundation. It must be able to carry the load of upper structure without any significant deformation due to important role in pile design. A part from empirical and numerical methods, axial pile bearing capacity can be predicted by pile driving analyzer test that use wave equation analysis during the test. Prediction of the axial bearing capacity and its distribution can be achieved by combining wave equation analysis with dynamic pile monitoring. This paper compares the axial capacity of pile obtained from PDA records with predicted axial capacities obtained using empirical, numerical, and interpretation of static load test method. The empirical method used NSPT data from bore testing that conduct in site, finite element method that uses in this study is Plaxis 8.6. Both of them was compared with PDA test result of axial bearing capacity. There is a difference value of the calculation results of axial pile bearing capacity and foundation settlement. Comparing with PDA, from empirical method has smallest deviation for axial bearing capacity which equal to -268.45 kN with percentage -6.05%, smallest settlement equal to 0,0044 m. Plaxis result shows that distinction between Qult result equal to -11.00 kN with percentage -0.24% and settlement of foundation equal to 0,005 m. From interpretation of static loading test method smallest deviation for Qult which equal to -40,00 kN, with percentage -0,90%, and smallest settlement equal to 0,0055 m. So, from all method the smallest deviation for Qult and PDA result is used finite element method. This is due to many data parameters has been inputted and analyzed in the Plaxis program, so the results of calculation analysis are more detailed and closer to the situation in the research site. Differences in axial bearing capacity can be caused by the test was carried out which depends on the accuracy of operator and parameters that used in the calculations.

A finite element method, as well as the algorithm and the program for solid reinforced concrete structures analysis have been developed, taking into account plastic deformations of concrete. A modified Willam & Warnke failure criterion was used, supplemented by a flow criterion. Two models of volumetric deformation of concrete have been developed: an elastic model under brittle fracture and an ideal elastic-plastic model. An eight-node solid finite element with linear approximation of displacement functions, which implements the deformation models above mentioned, is constructed. This finite element is adapted to the PRINS computational software, and as part of this program it can be used for physically nonlinear analysis of building structures containing three-dimensional reinforced concrete elements. Modern building codes prescribe to carry out calculations of concrete and reinforced concrete structures in a nonlinear formulation, taking into account the real properties of concrete and reinforcement. To verify the developed finite element, a series of test calculations of a beam in the condition of pure bending was carried out. Comparison of the calculation results with experimental data confirmed the high accuracy and reliability of the results obtained.

Un-bonded fiber reinforced elastomeric isolator (U-FREI) is a relatively new type of multi-layer elastomeric isolator in which fiber layers are used as reinforcement to replace steel sheets in conventional steel reinforced elastomeric isolators. It is installed directly between the substructure and superstructure without any connection at the interfaces. Most of the previous studies on the U-FREIs supported to the base-isolated buildings are masonry or stone structures. In this study, the dynamic responses of a reinforced concrete (RC) building supported on square U-FREIs under the action of recorded real time-history ground motions of earthquakes are investigated by finite element analysis using SAP2000 software. A hypothetical 4-storey reinforced concrete building constructed in Vietnam is selected for the study. Comparison of the dynamic responses of the base-isolated building and corresponding fixed-base building is carried out to evaluate the seismic vulnerability of the base-isolated building under earthquakes. Finite element analysis results show that peak values of floor acceleration and inter-storey drifts at different floor levels, and peak value of base shear of the base-isolated building are lower than those of the corresponding fixed-base building. The U-FREIs are found to be very effective in reducing seismic vulnerability of low and mid-rise RC buildings.

Образование осадка на стенках труб и каналов оказывают существенное влияние на эффективность и надежность технологического оборудования. В статье рассмотрено влияние образование осадка на процесс ультрафильтрации сточных вод комбината железобетонных конструкций, представляющие водомасляные эмульсии с большим содержанием взвешенных веществ. На основе развитой ранее Е.П. Медниковым теории турбулентной миграции частиц в сдвиговом турбулентном потоке газа получено решение задач об осаждении частиц на стенки круглых каналов из потока вязких жидкостей в широком диапазоне числа Шмидта. Получены уравнения для определения коэффициента массоотдачи из ядра потока к стенкам канала для двухслойного пограничного слоя по теории Прандтля, трехслойного – Кармана и модернизированного трехслойного Ландау-Левича. Результаты расчетов коэффициента массоотдачи частиц от ядра потока к поверхности канала по предложенной модернизированной модели показали наибольшую интенсивность осаждения частиц диаметром от 10 до 40 мкм. Адекватность модели была проверена путем сравнения расчетных параметров с результатами известных отечественных и зарубежных исследователей и показала хорошую верификацию.

The combined foundation plates, having circular form and consisting of several parts which have different laws of thickness variation, are under study. The constructions under examination are subjected to an action of antisymmetric load distributed along circumferences according to the laws or . Similar problems occur in the cases of seismic and wind loads. The interaction with elastic foundation is taking into account. The conditions of the construction’s different parts conjugation are fulfilled. In this work for solution of such problems the analytical approach is used for the first time. The method of compensating loads (MCL) is applied. The solutions are obtained in closed form in terms of Bessel functions. As an example the foundation plate, consisting of two parts, is considered in detail. The inner part of the slab under study has the variable thickness, the outer one has the constant thickness.

The Semarang-Demak Toll Road was planned with detailed procedures to address disorganized road networks, increased traffic volumes, congestion, land subsidence, and tidal floods. It has toll entrances in Semarang, Genuk, and Sayung sub-districts and ends in Demak City. Its purpose is to minimize traffic jams, provide access to tourist cities, and serve as a tidal barrier sea embankment. The formwork support system's proper design is crucial to ensure the safe construction of the main structure. A unique disk lock and steel tubular scaffold are utilized for a slab-on-pile structure employing a flying falsework system. This approach results in a structurally sound and secure construction that is not susceptible to twisting, providing quick erection and disassembly, significantly improving construction efficiency. The system was employed in a portion of the Semarang-Demak toll road project, and its efficacy was evaluated using finite element analysis software. The software provides security and convenience in analyzing structures, paying attention to the nominal strength of each steel profile and the internal forces at work. All components are safe as their actual deflection falls within the maximum limit.

This article presents the results of the development and verification of a dynamic finite element model of a high-pressure concrete hydraulic structure (Sayano-Shushenskaya HPP). A brief analysis of previously developed models of the hydraulic structure was carried out. An algorithm for sequential refinement of the results of dynamic calculations of hydraulic structures, significant factors and approaches to modeling the dynamic stress-strain state of hydraulic structures is presented.

На примере моделирования напряжённого состояния эксплуатируемых цилиндрических резервуаров для хранения нефтепродуктов с несовершенствами геометрической формы реализован метод численного исследования тонкостенных оболочек инженерных сооружений, который включает составление и численное решение массива дифференциальных уравнений с последующей интерполяцией результатов и определением экстремальных значений перемещений (или напряжений), возникающих в резервуаре от действия гидростатической нагрузки с учётом геометрической и конструктивной нелинейности. Для реализации предложенного метода используется геометрическая теория многомерной интерполяции и аппроксимации, включая новый способ учёта начальных условий дифференциального уравнения. Последний заключается в параллельном переносе численного решения в нужную точку, координаты которой соответствуют начальным условиям. В результате удалось достичь значительного повышения быстродействия численного решения при сохранении достаточной для инженерных расчётов точности.

is presented. The method is based on the use of the algebraic theorem of P.L. Pasternak and on the new properties of the Duhamel integral, which are obtained for a dissipative system with internal friction of the material, which is taken into account on the basis of the non-proportional damping model. For displacements, velocities and accelerations, the dynamic reaction equations are written in the form of systems of linear equations and their symmetrical structure is shown. The functional dependence of the force parameters of the calculation model and the corresponding kinematic parameters of the reaction is determined by an arbitrary scalar function of time. An extended interpretation of the reciprocity theorems is given and sufficient conditions for their fulfillment are formulated, which consist in the requirement that the matrix differential operator of the equation of motion be symmetrical. New laws of reciprocity in dissipative systems are formulated and proved. The reciprocity of the product between the velocities / accelerations of masses and nodal forces is established. In contrast to the well-known theorem on the reciprocity of possible work, these laws are theorems on the 1st / 2nd derivative of possible work with respect to time and therefore go beyond the Betti principle. For particular cases of these theorems, the reciprocity of velocities and reciprocity of accelerations is shown. Expressions of general and particular theorems have a fairly simple mathematical form that does not require recourse to integral transformations, and are presented in an analytical form.

Present paper proposes a computation method for a coupled heat and mass transfer problem within the porous media where the heat conductivity properties of the media undergo changes caused by the mass transfer. Heat and mass transfer processes are coupled through the inclusion of evaporation and condensation phenomena which in turn require the solution to an another the vapour transfer problem. This complex coupled problem re-sults in a system of both linear and non-linear second order partial differential equations that are spatially discre-tized by Finite Element Method. Temporal integration is carried out analytically. Thus, the proposed system of equations covering linear vapor transfer problem, linear filtration problem and non-linear heat transfer problem is transformed into a system of both linear and non-linear first order ordinary differential equations being solved by semi-analytical method. Picard approach of successive iterations is used for linearization of the equations. Convergent solution is achieved which is demonstrated on a sample problem herein below. Proposed method gives good insight on the processes taking place within the structures being subjected to temperature and vapor pressure gradients, including the residual effects of moisture accumulation, and assesses its impact on heat con-ductivity of materials that the structures consist of. Present study is a part of more extensive research on the ap-plication of semi-analytical methods in heat transfer problems, therefore it is not exhaustive and complete. Shortcomings of the method and its possible work-arounds as well as the topics for further studies are discussed in Conclusions and Further Studies section.