Vol 19, No 10 (2024)
Architecture and urban planning. Reconstruction and refurbishment
Renovation of industrial areas in the structure of rural settlements (on the example of the ceramic factory in the village of Nizhnie Tavolgi)
Abstract
Introduction. Renovation of preserved historical industrial territories is of great importance both for the development of rural settlements and regions as a whole, where a large number of currently underutilized and abandoned enterprises of the period of XIX – early XX centuries have been preserved. The main objective of this study is to present an example of a comprehensive approach to the issue of territory renovation, including all the main stages from pre-project and design analysis to the development of a project proposal.Materials and methods. The study of the design territory and objects is based on a comprehensive approach, including the analysis and use of Soviet and modern archival and bibliographic sources; collection and processing of documents, graphic and photographic materials, results of field survey (photo-fixation, measurements); systematization of research results.Results. The expediency of preservation and practical use of industrial enterprises is illustrated on the example of the developed project proposal for the renovation of the ceramic factory complex in the village of Nizhnie Tavolgi, Sverdlovsk region. The research materials present the prospects of their functional renewal and renovation in the modern conditions of rural settlements development.Conclusions. The research, popularization of significant objects that form the architectural appearance of settlements and their inclusion in modern realities is an important and necessary process both for the creation of a diverse quality environment, formation of place identity and education in the field of national history and culture.
Vestnik MGSU. 2024;19(10):1591-1605
1591-1605
Construction system design and layout planning. Construction mechanics. Bases and foundations, underground structures
Reliability factors for steel elements designed on the basis of computer numerical models
Abstract
Introduction. Today, there is an increasing reliance on computer computational models to assess the load-bearing capacity of building structures. However, a very small number of studies address issues of ensuring the reliability of the obtained results. In the current design practice, the design reliability of structures is provided by a system of partial reliability factors that take into account the uncertainty of random variable and the accuracy of the model. Therefore, fixing the values of reliability factors or the methodology for determining them in the design standards is especially important.Materials and methods. The proposed method for determining reliability factors and their values are based on the methods of reliability theory and probability theory. Statistical characteristics of random variables and accuracy of the computer model are based on the systematization, analysis and generalization of existing studies.Results. The paper presents a system of reliability factors and a method for determining them for the studied construction solutions and standardized parameters of computer models. The results of studies of statistical characteristics of the measure of accuracy of computer models are presented. The values of conversion coefficients are proposed, which allow taking into account different models of the material, the degree of discretization and the values of imperfections.Conclusions. In the field of design of building structures, two extreme cases of using computer numerical models from the position of knowledge of the studied object (for new structural solutions and for studied solutions) and two extreme cases from the position of knowledge of model parameters (validated (standardized) or non-validated (non-standardized) computer model parameters are used). Depending on the case under consideration, model verification procedures should be specified and ways to ensure design reliability should be assigned.
Vestnik MGSU. 2024;19(10):1606-1616
1606-1616
Construction material engineering
Investigation of properties of chemical anchor on the basis of epoxy resin
Abstract
Introduction. With the withdrawal of foreign companies from the Russian market there is a need for domestically produced bonded chemical anchors. The properties of the first fully locally produced bonded anchor UTECH HITRE500 based on epoxy resin are studied.Materials and methods. Glass transition temperature was determined according to GOST 32618.2–2014 on the TMA Q400 device; bending strength was determined according to GOST 4648–2014, compressive strength — according to GOST 4651–2014; pullout bond strength of adhesive composition to concrete was determined according to GOST R 58387–2019 with the help of Instron 3382 testing machine.Results. The following characteristics of the bonded anchor were determined during tests: glass transition temperature, bending strength, bending elastic modulus, compressive strength, ultimate resistance of bonding resistance to breakout at operating temperatures: +23, +42, +70, –60 °С, as well as the time for which the chemical anchor gains 97.7 % breakout strength when curing at air temperature –10 °С (10 days). It was established that when the specimens cured for 1 day at room temperature are kept at temperatures of +42 and +70 °С, the ultimate pullout bond strength decreases significantly (by 29.7 and 64.7 % respectively). It was found out that when the specimens cured for 1 day at room temperature, were tested at –60 °С the pullout strength slightly increased compared to the control specimens (4.6 % higher).Conclusions. The results of tests of the first fully locally produced chemical anchor UTECH HITRE500 are presented. The glass transition temperature and physical and mechanical properties of the cured chemical anchor were determined. The time required for full bond strength gain in conditions of negative temperature –10 °C equal to 10 days was determined.
Vestnik MGSU. 2024;19(10):1617-1628
1617-1628
Structure and properties of magnesia stone obtained by activation of caustic dolomite
Abstract
Introduction. The solution of the actual problem of deficit of reserves of raw materials with high MgO content by involving low-magnesian raw materials from dolomitized limestone into production is presented. For this purpose, it was proposed to increase the activity of the binder using preliminary mechanical activation in the vortex layer device. The aim of the study is to determine the effect of mechanical activation of caustic dolomite with plasticizers in the vortex layer device on the composition, structure and properties of magnesia stone.Materials and methods. Mechanical activation of the caustic dolomite was performed using a vortex layer device and the surface analysis of obtained specimens was carried out using a laser analyzer. X-ray analysis was used to determine the phase composition of the obtained specimens.Results. Regularities of hardening, phase composition of magnesia binders from duration of dispersion of caustic dolomite powder and concentration of plasticizing additives were investigated for the first time. A dense and strong matrix with high physical and mechanical properties is obtained. The effect of plasticizing additives based on lignosulfonate, polyester polycarboxylate and naphthalene sulfate formaldehyde on the composition, properties and structure of magnesia stone before and after activation of the binder is studied. The most effective additive concentrations were determined to increase the compression strength of magnesia stone from 35 to 120 % at the age of 28 days. The optimal duration range of activation was established and scientifically validated its impact on physical-chemical and morphological properties of the obtained specimens.Conclusions. Activation of magnesia binder with additives under optimal treatment conditions in the vortex layer device allows to obtain a magnesia stone with an adjustable set of properties: high density, compression strength in grades. The increase in strength of modified magnesia stones activated in vortex layer device with the addition of plasticizer is explained by higher density structure, low crystallite size and high density of dislocations.
Vestnik MGSU. 2024;19(10):1629-1640
1629-1640
Hydraulics. Geotechnique. Hydrotechnical construction
Theoretical basis for quantitative evaluation of the expansion of the leading hole of a crushed stone bored pile in a nonlinear setting
Abstract
Introduction. It is known that various methods are used to compact soft soils at depth, including the creation of soil columns by volumetric expansion of a portion of material (crushed stone, sand, etc.) under the influence of vertical load at the bottom of the well. With an increase in vertical load, the diameter of the working material increases to a certain value, resulting in significant radial and tangential stresses in the surrounding soft soil. This work is devoted to the development of the theoretical foundations for the manufacture of crushed stone bored piles that make it possible to quantify the stress-strain state in a soil cylinder due to the expansion of the diameter of the leading well. The formulation and solution of the problem of estimating the stress-strain state of a thick-walled soil cylinder of limited dimensions (diameter, height) with the diameter of a well are presented. Essentially, this is the well-known Lame problem of a thick-walled pipe.Materials and methods. The problem was considered in linear and nonlinear formulations. The solution was obtained by the analytical method. To estimate the stress-strain state of a thick-walled soil cylinder, the solution to the Lame problem of a thick-walled pipe and the system of Genki physical equations was used.Results. The expressions are obtained to determine the radial displacement of the borehole wall, radial and tangential stresses in the soil cylinder. The curves dependency of the radial displacement on radial pressure of borehole wall are shown. The achieved results are illustrated with graphics.Conclusions. The obtained solutions can be used to determine the radial displacement of the borehole wall during deep compaction of soft soils in linear and nonlinear formulations by adding crushed stone columns. The curves dependency of the radial displacement on radial pressure of borehole wall with various stiffness and strength parameters of the surrounding soils, as well as geometric parameters are presented.
Vestnik MGSU. 2024;19(10):1641-1650
1641-1650
Engineering systems in construction
Sanitary and hygienic issues in the design of individual heat supply systems
Abstract
Introduction. In the case of individual construction, the existing design standards for district heating systems are of a reference nature. The owner of the household determines how much hot water he needs, what the temperature in the room should be. It is important that fire safety, environmental standards, sanitary standards and standards of energy allocated per household are not violated. The parameters of HWS are quantitative. There are questions about the quality of sanitary water that has contact with human skin. There are engineering solutions that can eliminate or significantly reduce these risks. It is advisable to apply these engineering solutions at the design stage.Materials and methods. Based on the generalization of data from scientific sources and published cases of mass diseases, the main types of pathogenic bacteria occurring in individual water and heat supply systems were identified. These are Legionella and Pseudomonas aeruginosa. The thresholds and conditions of viability of these bacteria are considered. The main causes that cause the risks of growth of pathogenic bacteria are classified.Results. Requirements of observance of complex technical measures at designing consist in necessity of selection of the equipment of systems of individual heat supply at observance of conditions of control of water intake, maintenance of preliminary heating of water up to temperature 65 °С in systems of accumulation type, constant circulation of water in circuits of water supply, use of flowing water heaters, selection of pipes.Conclusions. The use of technical solutions for heat supply systems of individual construction facilities can significantly reduce or completely eliminate the risks associated with the possibility of pathogenic bacteria and diseases of people living in households.
Vestnik MGSU. 2024;19(10):1651-1665
1651-1665
Technology and organization of construction. Economics and management in construction
Application of function-oriented modelling systems in construction control implementation
Abstract
Introduction. The study of functional dependencies between the main participants of construction control, such as technical customer, general contractor and general designer, is carried out.Materials and methods. The structure of their interaction is presented in the form of a flowchart, which is drawn up using function-oriented analysis methodology. Presentation of information in the form of a flowchart makes it possible to analyze the interaction of participants at each stage of construction control. Also, integration of IDEF0 modelling method allows to analyze and correct the relationships between functional blocks.Results. Construction control decomposition is created by forming functional blocks, which consist of the main stages of construction control realization. Then a complex decomposition of these blocks is performed, which allows us to obtain a “micro-level” of each of the main blocks. This approach to the formation of interrelationships between the main participants of construction control will subsequently allow to identify the main problems that are encountered at the stage of control and will help to improve the efficiency and structuring of the construction control system.Conclusions. It is proposed to take a new look at construction control from the point of view of functional interaction of control participants, which in the future will lead to a reduction in the number of poor-quality construction products or operations.
Vestnik MGSU. 2024;19(10):1666-1675
1666-1675
Formation of an effective schedule of work during the construction of a monolithic reinforced concrete house
Abstract
Introduction. The existing principles of construction organization, based on early developments that do not take into account the current situation, to a large extent become an obstacle to the development of the construction industry. The current situation requires the introduction of new approaches in construction management, allowing to adapt to changing economic conditions, and contributing to a reduction in the duration of construction. The task of the study was to develop a project for the organization of work, which allows reducing the time for the construction of a monolithic floor from 14 to 6 working days. The scientific novelty of the work lies in the development of such combinations of various technological stages that made it possible to reduce the duration of construction without violating construction production technologies; to make decisions promptly in a specific situation and maintain full control over the consumption of building materials, possible losses and labour costs not aimed at fulfilling the main tasks, in order to improve the technical and economic indicators of construction.Materials and methods. Standard technological processes and regulatory documents were studied. It is revealed that the optimization of technological processes and the use of the principles of “lean construction” contributes to reducing labour costs and consumption of building materials, increasing productivity and improving quality; the development and implementation of technology depends on the final goal and task of the project, implies a sequence of decision-making.Results. In the course of the research, an algorithm for making specific decisions was developed. To achieve this goal, an analysis of the technology of monolithic housing construction was carried out, the moments that have a direct impact on increasing the duration of construction and possible losses were identified, and options for making changes that contribute to solving these problems were proposed.Conclusions. The proposed work organization system may have great potential in the future, despite its simplicity. The developed technical and technological solutions aimed at a lean attitude in production and organization of construction will greatly contribute to improving the competitiveness of construction companies, reducing the cost of production by reducing direct costs, increasing productivity and improving product quality. The stages of further implementation will be built entirely on the justification and development of a lean construction management model, and steps to implement this system, determining the area of responsibility of each participant.
Vestnik MGSU. 2024;19(10):1676-1686
1676-1686
Methodology of calculation of time reserves when planning the duration of NPP construction
Abstract
Introduction. The issues of risk and problem situations arising during the construction of nuclear power plants, as well as methods of response and prevention of such scenarios are considered. The available analogues of the developed system among the known information systems which carry out calculations of calendar-network models and construction completion forecasts are analyzed.Materials and methods. In particular, the methodology of creating a system of time reservation during the formation and approval of calendar-network schedules of construction and installation works is highlighted. A step-by-step plan of initial data preparation, necessary statistical analysis and direct calculation of time reserves by Monte-Carlo method using the software package of the same name developed within the framework of the current research is presented. As the initial data, the information of the analysis of disruption of the deadlines of already completed works at reference NPP with a certain classification, as well as the results of an expert survey on the influence of internal and external factors on the duration of plant construction are used.Results. Examples of using the development within the process of managing the construction schedule of El-Dabaa NPP in the Arab Republic of Egypt are described. The possibility of applying this methodology at different levels of project management is indicated.Conclusions. A generalized conclusion on the issue of determining the duration of construction of nuclear power plants taking into account the formation of time reserves for work schedules, a step-by-step plan for calculating time reserves and positive approbation of the methodology for NPP construction is formulated.
Vestnik MGSU. 2024;19(10):1687-1695
1687-1695
Review of experience in the construction of NPP using modular structures with external sheet reinforcement
Abstract
Introduction. To increase the competitiveness of domestic NPP projects, it is necessary to reduce the construction time to 36 months. One of the ways to solve this problem is industrialization of the construction process, which uses prefabricated elements in the form of volumetric units with sheet steel cladding. The paper reviews open sources of information on the experience of erecting nuclear power plants using modular reinforced concrete structures with external sheet reinforcement. The following projects were considered: AR-1000 by Westinghouse (USA) and ATS-1000 (SNERDI).Materials and methods. On the basis of analysis, generalization and systematization of information obtained from open sources, the authors reviewed the practical experience of application of structures with external sheet reinforcement in the construction of NPP (under the AP-1000 and CAP-1000 projects) at the following facilities: Sanmen, Haiyang, Xudabao and Lianjiang (China), V.C. Summer and Vogle (USA).Results. The main method of erection in the implementation of NPP projects using modular reinforced concrete structures with external sheet reinforcement was the erection of extra-large units using the open-top technology. The use of such technology imposes higher requirements to the design documentation, manufacturing of unit modules requires strict control of logistic risks. Lack of quality control methods for compaction of monolithic concrete placed in the structure increases the requirements to the quality of concrete mixtures and technology of their placement.Conclusions. In general, the technology of modular construction using reinforced concrete structures with external sheet reinforcement allows to significantly reduce labor costs of erecting structures directly on the construction site. However, based on the results of analyzing the experience of implementation of AR-1000 and SAR-1000 design solutions, it was found that additional logistical risks and risks of ensuring the quality of monolithic concrete placement arise when implementing this technology.
Vestnik MGSU. 2024;19(10):1696-1712
1696-1712