Introduction. The paper is devoted to one of the objects of cultural heritage forming the architectural appearance of the Musin-Pushkin Estate at the intersection of Dobroslobodskaya and Spartakovskaya Streets in Moscow (now the complex of buildings of the Moscow State University of Civil Engineering) — the main house of the ensemble. This building has a status of federal cultural heritage object and has undergone numerous renovations and reorganizations by present time, and we can see the signs of it in the interiors and on the facades of the monument. Besides, the monument has a great construction history and includes building parts of different periods and architectural styles, which were detected as a result of historical-architectural and field studies. Thus, D.A. Shepelev’s house became the core of the ensemble on “Razgulay”, which later became part of the main building of Musin-Pushkin Estate. The results of the historical-architectural and field studies were considered in the article “D.A. Shepelev’s house as part of the main house of the Musin-Pushkin Estate in Moscow according to the materials of historical-architectural research”, published in the journal Vestnik MGSU. No. 6. 2023. The main aim of this work — to consider information from historical-architectural and field studies in a range of the similar, typologically and stylistically close constructions. This will allow to present the authentic appearance of the disappeared building with the greatest reliability and to give its graphical reconstruction.

Materials and methods. The study of the monument was based on the method of comprehensive source study, which includes the search and analysis of sources, literature, and selection of analogues. Studying of the object among stylistically and typologically similar buildings was based on historical-architectural and field studies with using of comparative method.

Results. As a result of the conducted research, the materials revealed in the course of historical-architectural and field studies, when considering them in the circle of analogues, received their stylistic identification and found confirmation in the considered, stylistically and typologically close buildings. The conducted analysis allowed us to propose a reconstruction of the original appearance of D.A. Shepelev’s house with baroque facade decoration typical for that time.

Conclusions. The proposed reconstruction is the result of complex research, which allows to present the original appearance of the building, which became the basis for the now existing main house of the Musin-Pushkin estate, although this reconstruction does not pursue the purpose of its recreation. It only marks the original appearance of the monument and reveals one of the pages in the history of such a significant for Moscow estate complex.

Introduction. This paper presents the results of the decomposition of the synthesized free damped vibrations of a linear cantilever dynamic model into elementary components using singular value decomposition of the displacement matrix.

Materials and methods. The well-known representation of a rectangular matrix in the form of a product of three matrix multipliers, called singular value decomposition (SVD), was used in the study.

Results. Representing the dynamic response of a structure in a certain matrix form allows for the results of the singular value decomposition to have a clear physical interpretation: the left singular vectors approximate the eigenvectors, the singular values themselves determine the contribution of individual eigenmodes to the overall dynamic response, and the products of singular values and right singular vectors approximate the modal coordinates of the dynamic system at the time under consideration. Singular value decomposition allows to “automatically” obtain an a priori vector basis based on the external manifestations of the dynamic reaction (displacement, velocity or acceleration of the points of the structure), whereas the eigenvectors traditionally used for these purposes are a posteriori basis based on the study of the internal inertia, stiffness and damping properties.

Conclusions. This study confirmed the possibility of using displacement matrix SVD to determine the major dynamic parameters of linear dynamic systems: eigenmodes, eigenfrequencies and quantitative damping parameters. All stages of obtaining and subsequent analysis of the dynamic response elementary components are easily automated, which allows to consider SVD as a basis for software development of automatic dynamic monitoring systems of structures under construction and in operation.

Introduction. A nonlinear differential equation of the third order with a polynomial right part of the seventh degree describing wave processes in beams is considered. When studying this class of equations, generally unsolvable in quadrature, the authors use a method allowing to obtain an analytical approximate solution. This kind of research is based on the solution of several mathematical problems. The paper generalizes previously obtained results of the study of one class of nonlinear differential equations with moving singularities to the complex domain.

Materials and methods. The problem of finding the exact limits of application of the approximate solution of a nonlinear differential equation in the neighborhood of a moving singular point is considered. Previously, the boundaries of the application area of the approximate solution were determined on the basis of the theorem of unique existence, but further, the obtained area was reduced due to the perturbation of the moving singular point. Applying elements of differential calculus to estimate the error of the solution, in this work, it is possible to expand the scope of the approximate solution and bring it closer to the initially obtained area.

Results. The exact boundaries of the area of application of the approximate solution are obtained. Theoretical provisions are confirmed by numerical calculations, which characterizes their reliability. Two numerical experiments are considered. In the first one, a point falling under the previous and new area obtained in this paper is taken. In the second, the point falling only under the new theorem is taken.

Conclusions. The author’s approach of the method of analytical approximate solution is further developed on the example of the considered class of nonlinear equations. The paper summarizes the results obtained earlier in the research of the exact limits of application of the approximate solution of the considered class of equations in the vicinity of a moving singular point in the complex domain. The presented studies are confirmed by numerical experiments.

Introduction. The paper describes a fundamentally new method of passive damping of vibrations of a structure in the vicinity of its resonant frequencies. The method is based on the use of piezoeffect. For this purpose, piezoelectric elements are added to the structure, which serve as energy converters (mechanical energy into electrical energy and vice versa).

Materials and methods. Piezoelectric elements are polarized piezoceramics with electrodes. Two different types of electrical conditions on the electrodes are used for passive vibration damping: a) the electrodes are short-circuited and b) disconnected electrodes. By changing the electrical conditions on the electrodes, we change the boundary value problem. The spectrum of natural frequencies of the boundary value problem for a structure with short-circuited electrodes differs from the spectrum of natural frequencies of the boundary value problem for the same structure with disconnected electrodes. The idea of the method is as follows: let the vibration frequency of the structure with short-circuited electrodes approach its resonant frequency. Let us disconnect the electrodes, thereby changing the spectrum of natural frequencies of the structure. The vibration frequency, which is the resonant frequency for the structure with short-circuited electrodes, will not be resonant for the structure with disconnected electrodes. As a result of changes in electrical conditions, the amplitudes of the required quantities (deflection, bending moment, shearing force, etc.) will decrease significantly. To evaluate the effectiveness of passive vibration damping, a simple formula is proposed.

Results. For a beam undergoing forced bending vibrations in the vicinity of its resonant frequency, calculations were performed using the proposed method of passive vibration damping, tables of vibration damping efficiency in the vicinity of resonant frequencies were obtained, and graphs are plotted. The possibility of increasing the efficiency of vibration damping by choosing the direction of pre-polarization of the piezoelectric material, the location of the electrodes and their number was investigated.

Conclusions. The results of studies of passive vibration damping near resonant frequencies using the piezoeeffect confirmed the simplicity and reliability of the proposed method.

Introduction. The objects of the research are experimental specimens of glued laminated wood with a steel rod glued along the wood fibres in each of them. The subject of the research is the values of resistance of wood to pulling out or push-through of the rod glued along the fibres, as well as the compliance of the joint. The goal of the research is to calculate the resistance according to the test results and compare the obtained value with normative data. The relevance of the research is due to the widespread application in construction of glued wood structures and joints on glued rods. The obtained data can be used in calculation models and in the calculation of nodes.

Materials and methods. Experiment and calculation methods are used in the research.

Results. The results of five specimens were used to obtain the values of total deformations for each stage of loading. It occurred due to chipping of the wooden element along the fibres at the border of the adhesive joint and the wood. Wood resistance and compliance values for each specimen were calculated and tabulated. The normative value of wood resistance was obtained. It exceeded the value specified in the normative document data. A numerical normative value of compliance was also obtained.

Conclusions. The excess of the resistance obtained from the experiment over the value in the normative document indicates its applicability with provided safety factor. In the calculation of unique structures according to special technical specifications, it is possible to use an increased resistance value obtained as the result of the experiment. The compliance of a rigid joint on rods glued along the fibres is small. In wooden structures it is not possible to avoid it completely.

Introduction. Petroleum bitumen is the main component of road surfaces, which play an important role in ensuring the safety and comfort of vehicle traffic. Over time, bitumen undergoes ageing, which leads to changes in its physical and chemical properties. Such changes cause a decrease in the quality of road surfaces, deterioration of their performance characteristics and reduction of durability. The analysis of research in the field of bitumen thermal stabilization, which is of great importance for optimization of technological processes at high temperatures, was carried out. The optimal composition of modified bitumen using stearic acid, industrial oil was determined.

Materials and methods. Bitumen undergoes serious changes during technological processes, during the transition from the bulk to the film state under the influence of high temperatures. Thus, thermal stability of bitumen is an important condition for preserving its quality at all stages of its life cycle. The issue of bitumen thermal stabilization with the use of stearic acid T-18 in combination with industrial oil I-20, which lead to increased resistance from external factors, is considered. To establish the degree of influence of modifying components on bitumen properties, a two-factor rotatable experiment with varying the amount of industrial oil and stearic acid additives, was performed.

Results. The compositions and properties of the obtained modified bitumen were studied. The analysis of the obtained results shows that the effect of stearic acid on bitumen penetration is about 6 times higher than the effect of industrial oil, while both components together have insignificant effect on the other studied properties of bitumen.

Conclusions. In order to further study thermal stability on the optimal versions of bitumen compositions, studies on mass retention of bitumen films at temperatures from 160 to 220 °C were performed. According to the obtained results, it was found that the effectiveness of stearic acid is manifested at higher temperatures and reaches values up to 25 %.

Introduction. This paper studies depressed construction sites and their presence on the territory of Arctic. Application of earth remote sensing technologies from space is indispensable for providing sub-satellite monitoring to identify emergency, damaged and abandoned construction objects in hard-to-reach regions. The purpose of the study is the possibility of deciphering depressed construction objects according to aerospace monitoring data. For the Arctic territories remote methods are relevant because of unfavorable meteorological conditions of contact methods, as well as because of the depressed nature of most settlements. Depressed construction sites are one of the main features of the surveyed territories. In the world practice, there are certain methods for deciphering depressed structures. These are hierarchical deep learning method based on Google Street View images, information modelling of historical buildings, photogrammetry using UAVs, 3D shooting.

Materials and methods. The research is carried out on the basis of satellite images of high spatial resolution, depicting territories with different lighting conditions, landscape and component composition of the Arctic surface. The subject of the research is a complex method of visual decoding of depressed construction objects.

Results. The areas and signs of deciphering, the relevance of deciphering of these objects in the Arctic region are presented. Examples of emergency and abandoned objects and their deciphering signs on satellite, ground and aerial photographs are given. The ecological aspect of depressed construction objects associated with the production of landfills and certain mechanisms of behavior in relation to land use is shown.

Conclusions. The methods of interpretation of depressed construction objects based on aerospace monitoring data considered in the paper allow to carry out their cadastral registration, mapping and systematization, to estimate quantitative and qualitative characteristics of these objects and depressiveness of the regions under study. This is most relevant for the Arctic region.

Introduction. To prepare territorial planning documents, during design and construction it is necessary to take into account the requirements for organizing a safe living environment, assess the risks of negative impact of surface waters, including the possibility of flooding of the development area. For this purpose, engineering and hydrometeorological surveys are carried out, the maximum estimated flow rates and water levels in the nearest water bodies are determined. When performing hydrological calculations, an important role is given to quantitative indicators of precipitation, including maximum daily precipitation. The article considers a method of increasing the accuracy of modelling the maximum daily rainfall on the example of meteorological stations in the Kaliningrad region.

Materials and methods. Data arrays of the results of precipitation observations at four weather stations — Sovetsk (26614), Baltiysk (26701), Kaliningrad (26702), Zheleznodorozhny (26706) were processed in Mathcad. The main source of observational results is specialized datasets for climate research for the period from 1977 to 2021.

Results. A significant stochastic relationship between the annual precipitation amounts for the indicated meteorological stations and a weak one between the maximum values of 24-hour precipitation amounts for the year were determined. Numerical parameters of the series of maximum precipitation amounts at four meteorological stations in the Kaliningrad region for 1977–2021 years are calculated. The relative excess of the values of the maximum 24-hour precipitation over the values of the maximum daily amounts at the weather stations Sovetsk, Baltiysk, Kaliningrad, Zheleznodorozhny was calculated.

Conclusions. It has been established that with the help of 8-term observations of precipitation, it is possible to increase the accuracy of calculation of the maximum amounts of daily (24-hour) precipitation. The results obtained can be used in the analysis of precipitation and calculation of the maximum discharges of rain floods on rivers with a catchment area of less than 200 km2.

Introduction. Heat exchangers are important equipment in modern heat supply. This equipment is very common. Modernization of shell-and-tube heat exchangers is an important direction. The purpose of modernization is to increase the heat transfer coefficient. A heat exchanger which tubes are equipped with plates was developed. Cylindrical turbulators (ribs) are located on the plates. The experiment is important for the development of a new heat exchanger. The experimental conditions correspond to the real heat supply system.

Materials and methods. The full-scale stand was used for the experiment. The stand represents an independent heating system of the building. The planning of the experiment is based on the temperature schedule of the boiler house and the temperature schedule for the consumer. Mathematical processing of the results was carried out.

Results. For a heat exchanger (with turbulators), the values of the heat transfer coefficient were obtained at different outdoor temperatures during the heating period. The dependences of the heat transfer coefficient on the temperature difference are obtained. This was done at coolant velocities in the annular space of 0.16 and 0.32 m/s. Discrepancies are adequate, statistically significantly describe the results of the experiment. The heat transfer coefficient of the heat exchanger (with turbulators) turned out to be greater than that of the serial one. This parameter is 22 % more at a speed of 0.16 m/s, 23 % more at a speed of 0.32 m/s on average for the heating period.

Conclusions. The heat transfer coefficient increased for the heat exchanger with turbulators by an average of 23 %. The turbulence of the coolant affects this increase. The dimensions will be much smaller for such a heat exchanger than for an apparatus with smooth tubes. Tube with cylindrical turbulators is recommended for use in different equipment. This can be used in shell-and-tube heat exchangers, air heaters, heaters, economizers.

Introduction. The objective of the study is to analyze the prospects of application of phase change materials in building structures. The relevance of the work is due to the industry trend to reduce the consumption of heat energy by buildings through the use of modern thermal insulation materials and enclosing structures. Phase change materials produced in industrial volumes and used in construction in foreign countries are chosen as the object of research. The ability of these materials to absorb and release heat energy can be used to improve the thermal characteristics of buildings. Analysis of the possibility of using these materials in building structures was carried out for three cities of the Russian Federation: Moscow, St. Petersburg and Sochi.

Materials and methods. The efficiency of the use of phase change materials in building structures was carried out by means of energy modelling of the building using the Conduction Finite Difference algorithm in the EnergyPlus programme, taking into account climatic conditions and energy consumption for heating and cooling of the building. The calculation was performed for structures including phase change materials (3 different materials with phase change), and without them.

Results. The values of energy consumption for space heating and cooling, absolute and relative energy savings from the use of phase change materials were determined.

Conclusions. The analysis showed that the energy and economic effect from the application of materials with phase change in building structures is from 2 to 13 % and depends on both the type of material and the region of application.

Introduction. The main problem is discussed that is related to application of reverse osmosis membranes method for quality drinking water production from underground water sources that contain dissolved contaminants dangerous for health such as: fluoride, ammonia, lithium, strontium, arsenic, boron etc. It is also mentioned that reverse osmosis is currently efficiently used for drinking water production. The main goal of the present work was evaluation of the new developed method efficiency and calculation of the operational costs to compare with conventional approach to use reverse osmosis to remove lithium from the ground water. Present article demonstrates results of research aimed at developing a new approach to change the ratio of monovalent and bivalent ions in the permeate of nanofiltration membranes. An example of water with high lithium content that exceeds normative value by 24 times is discussed. The developed technique of ion separation is applied and experimental results are demonstrated, thus providing low lithium concentration in product water with increased calcium and TDS by 5 times as compared to the conventional use of reverse osmosis membranes. Operational costs are evaluated and compared with conventionally used approach to produce drinking quality water from ground water.

Materials and methods. A series of experiments were conducted to remove lithium from ground water and to demonstrate the efficiency of the new developed method of ion separation. Experimental results of permeate and concentrate separation are presented compared to reverse osmosis that provided the increase of calcium and TDS values in the product water by 4–5 times compared to permeate produced by reverse osmosis membranes. The economical evaluation of the main technical parameters of the developed method involved calculation of the required membrane area and the number of membrane elements at each stage, calcium carbonate scaling rates and reagent consumption to prevent scaling as well as the amounts of concentrate discharges into the sewer.

Results. Experimental dependencies of the efficiency of different dissolved contaminants removal from the ground water using different types of membranes depending on the recovery values were obtained. Experimentally obtained results confirmed the possibility to increase the calcium concentration and TDS values of the product water by 4–5 times leaving the lithium concentration at the same level. A flow diagram of the developed process is demonstrated based on experimentally obtained results. The increase of product water TDS facilitates the further reduction of concentrate flow rate and operational costs. Design characteristics to calculate operational costs for two options (conventional and proposed) are presented. Economical comparison was performed using results of calculations of membrane surface area on each stage of membrane treatment, scaling rates, reagent consumption, concentrate discharges.

Conclusions. Application of reverse osmosis for removal of monovalent contaminants (such as: lithium, ammonia, boron) from ground water results, in reduction of TDS values that requires additional costs to provide permeate conditioning. Operation of reverse osmosis facilities also is distinguished by scaling problems that also requires additional operational costs to prevent and remove scale deposits. In this paper, a new approach is proposed to apply nanofiltration membranes using double stage treatment and separate monovalent and bivalent ions and increase calcium and TDS content in product water leaving the lithium content at the extreme level. The use of developed method enables to reduce operational costs due to lower membrane replacement costs, reagent consumption for scale prevention and concentrate discharges.

Introduction. In the Russian construction industry, the transition to information modelling technologies (BIM) is defined by the government as a priority task. Officially, the transition to BIM was planned in Russia in 2014, when the “Plan of phased introduction of information modelling technologies in the field of industrial and civil construction” was adopted, which is still, unfortunately, at the initial stage of implementation due to the following barriers: insufficiently developed regulatory and legal framework; shortage of BIM specialists; high cost of software (mostly foreign), as well as the lack of tested methods of economic justification of the feasibility of the application of BIM. The article analyzes the world experience of the countries, which have successfully implemented BIM in production, and reveals the main reasons for the unacceptably low rates of BIM usage in the construction industry. The authors of the article offer the algorithm of activation of introduction of BIM in construction, algorithm of actions for software choosing and a technique for calculation of the expected economic effect of the use of information modelling technologies in investment and building projects realization. The final results of testing in practice the developed methodological tools are given.

Materials and methods. The research is based on system, process and situational approaches, methods of comparative and factor analysis of the results of foreign and domestic experience, as well as methods of economic-mathematical and graphic modelling. This methodological set allowed assessing the influence of factor space on the processes of applying BIM at the stages of the life cycle of ICP and to propose an algorithm of actions to intensify the implementation of BIM in the domestic construction industry.

Results. The analysis of the results and outcomes of the use of BIM in Russia and in developed foreign countries, carried out by the authors, made it possible to establish the lag and identify its main causes, as well as outline ways to eliminate them.

Conclusions. The proposed algorithms, economic and mathematical model for calculating the expected economic effect will enable Russian construction companies to reasonably approach the process of introducing BIM in the implementation of investment and construction projects.

Introduction. The relevance of the study is due to the current preparation of the construction industry in Russia for the introduction of a mandatory requirement for the use of building information modelling (BIM) when working with objects financed from the budget. Such a requirement was supposed to come into force in 2022, but due to a number of circumstances, it was postponed. The article presents the results of the study, the purpose of which was to identify the opinions of representatives of the investment and construction sector on the main directions of state support of BIM implementation with the determination of the relationship between the opinions of respondents and the type of activity of their organizations. The results of the study will help to concentrate efforts on those that the industry needs the most. Identification of the respondents’ opinion in the context of the type of activity of their organizations will provide an opportunity for targeted application of state support measures in relation to those types of organizations that need them most urgently.

Materials and methods. Primary data for the study were collected by survey (questionnaire) and processed using the factor analysis method. At the same time, the type of activity of their organizations was chosen as a factor potentially influencing the opinion of respondents.

Results. The results of the analysis of respondents’ assessment of the effectiveness of measures of state regulation of the BIM implementation in general for the entire sample are presented. Based on the division of respondents into groups by type of activity, a factor analysis to assess the effectiveness of measures of state regulation of the BIM implementation was carried out. An assessment of the most significant state support measures in our days for the BIM implementation was made The analysis was carried out both for the sample as a whole and for groups of respondents. The analysis revealed that different groups of respondents prefer different support measures.

Conclusions. It was found that the type of activity of the respondent’s organization has a significant impact on their opinion on the effectiveness of the state policy measures implemented by the time of the survey, as well as on the most timely and necessary measures that need to be implemented at present.

Introduction. The geopolitical and economic agenda for Russia’s economic sovereignty has required significant changes in the modes of production and, consequently, in the economic environment. The construction market is an extremely important and integral part of it in the conditions of increasing sanctions pressure. The analysis of the SMO period has convincingly proved the viability of market rules of business turnover in the investment and construction sector. None of its segments turned out to be in crisis and depression.

Materials and methods. Business activity grew frontally. Meanwhile, the observed time compression of the emergence of new growing external challenges, which revealed and made it possible to identify latent processes slowing down the modernization of the construction industry, prompted the authors to change the generally accepted perspective of studying the construction market from the use of the method of decomposition of its segments to the implementation of the methodological approach of “time management in restructured space” in order to complement the megapolis concept of settlement with the strategy of accelerated development of territories in the points and corridors of economic.

Results. The synthesized objectives of total acceleration of territorial, project, subject and resource maneuvering allowed to identify goals and objectives of transformation of commodity-money relations emerging within the construction market in the context of the selected types of capital construction. In this context, the authors have identified and disclosed the content of the following tasks of construction market development: providing spatial and temporal maneuverability of production capacities of market entities; synchronization and scaling of investment and construction processes; reshoring and technological import substitution; unfinished construction liquidation; supporting development rates of socially-oriented segment of construction market. Solving these tasks will require territorial, project, subject and resource front-end maneuvering. As practice has shown, this is impossible without institutionalization of a new toolkit of spatial-territorial development. Its goal is to fully realize the country’s geospatial advantage by mitigating the risks of the megacity concept of settlement, while simultaneously developing territories not only at points, but also along major spatial corridors of economic growth.

Conclusions. The article took into account approaches to accelerate the commissioning of various types of capital construction projects, which allowed the study to identify the directions of improving market mechanisms across different ССP. The unity of different directions is ensured by preventive methods of avoiding the conflict of economic interests, and the resolution of inevitably arising contradictions of development is proposed using methods of extrajudicial resolution of economic disputes, based on the use of spatial-territorial, legal, judicial, cost, construction and technical, environmental expertise.