Vol 19, No 2 (2024)

Introduction. The sustainability of territories of urban settlements (USs) and rural settlements (RSs) is one of the priority tasks of urban planning and socio-economic planning, and is also determined by the goal of integrated development of the territory. This issue is widely discussed in the scientific and technical literature, where the focus is on socio-economic, environmental and anthropogenic factors that characterize the urban system, which are used to obtain a quantitative indicator of the level of sustainability using entropy-weighted, (TOPSIS-Technique of Preference Similarity to the Ideal Solution) and other methods. At the same time, the importance of cultural heritage in sustainable development has not received enough attention. This paper presents the results of sustainability assessment of the impact of immovable tangible cultural heritage of eight Syrian cities based on a multi-criteria model.Materials and methods. The paper uses materials from open sources and statistical data of municipal organizations, the selection of which is based on the Sustainable Development Goals (SDGs) and the system approach. The data include characteristics of social, historical-cultural, economic, environmental, engineering, transport subsystems of the city. The aim of the study is to determine a generalized index characterizing the sustainability of the city and the impact of its factors on its importance of cultural heritage in promoting socio-economic development and urban reconstruction after the military conflict.Results. Based on the presented model, calculations of the urban sustainability index (IS) of 8 Syrian cities — Damascus, Homs, Aleppo, Latakia, Palmyra, Daraa, Deir ez-Zor and Idlib for the period of 2010 (before the military conflict) and 2023 were performed, which showed a decrease in the sustainability index up to two times. This is due to the destruction of residential areas of engineering and transport systems, destruction of cultural heritage objects. It is also found that tangible cultural heritage has a great impact on the sustainability of the city system.Conclusions. The proposed model for determining the index of urban sustainability (IS) allows us to obtain a quantitative assessment and analyze the impact of each factor. It is shown that along with the restoration of residential areas and objects of engineering and transport infrastructure, it is necessary to carry out works to preserve objects of cultural heritage, the loss of which leads to a decrease in the sustainability of the city, the loss of its urban identity.

Introduction. Reinforced concrete structures of buildings have significant fire resistance, but high-temperature effects lead to changes in strength and deformation characteristics of concrete and reinforcement of structures. In addition, for prestressed reinforced concrete structures, fire impacts can be associated with partial or even complete loss of prestress. At the same time, it is the prestress of the reinforcement that makes it possible to limit the width of the crack opening and the deflection of reinforced concrete structures within acceptable limits.Materials and methods. The paper presents and analyzes the results of analytical calculations of the bearing capacity and serviceability of a prestressed reinforced concrete ribbed floor slab before and after high-temperature fire impact on it. After fire exposure, the calculations are carried out with a complete loss of pre-stressing by the reinforcement. The heating temperature of the concrete in the compressed zone and tension reinforcement in the calculated cross section of the floor slab is taken according to the results of experimental studies.Results. The comparison of the floor slab deflections obtained by calculation and experimentally indicates the presence of additional factors (temperature expansion of concrete and reinforcement, high-temperature creep of reinforcement) that determine the increased value of the experimental floor slab deflection compared to the calculated one. The structural solution of the floor slab is analyzed, the feasibility of increasing the area of longitudinal tensile reinforcement to increase the bearing capacity and reduce the crack opening width in the slab is considered. The effect of fire protection on the heating temperature of the concrete in the compressed zone and the tensile reinforcement of the slab is shown.Conclusions. An analysis of the results of calculating a prestressed concrete ribbed floor slab before and after a fire showed a slight decrease in its bearing capacity after fire impact, an increase in the width of the crack opening and a significant increase in the deflection of the slab.

Introduction. The paper illustrates the necessity and place of the problem of stability assessment of lifting devices applied for excavation in cramped conditions, which are typical for urban areas with dense urban development when laying underground transport facilities on the example of the open method of works on the construction of the Moscow Metro.Materials and methods. Two sites on the territory of Moscow and different cranes of Liebherr company were considered in order to investigate the influence of geotechnical parameters on stability and safety of heavy lifting equipment. In addition, numerical modelling was carried out to determine displacements and deformations at different locations of the crane with respect to the excavation fence.Results. Horizontal and vertical displacements and total deformations of the pit fence were obtained by means of numerical modelling with the use of geotechnical software systems PLAXIS 2D and PLAXIS 3D. Among other things, we analyzed the usage of PAG slabs, as well as construction of the top tier of the spacing system with the use of 1.5 × 1.5 m inventory slabs.Conclusions. The relevant issue is an analytical calculation for situations that can arise in solving practical problems, in particular, in the development of the project of works for the installation of a lifting device near the pit with a fence. Surface layers of soils (up to 6 m) have a special and primary influence on the result of the calculation. If the lifting device is installed in bulk soil of natural origin, it is mandatory to replace it with a harder soil or to lay additional concrete slabs with a larger area to reduce the direct load on the ground. In special cases, the numerical modelling should be performed separately for heavy truck cranes with a lifting capacity of 250 tons and more, provided that the guardrail is made without a spacing system (“cantilever type”).

Introduction. This research is a consolidated study of recycling in the construction industry. The recycling of construction and polymer industry waste is analyzed. Currently used methods and technologies of cross-linked polyethylene waste recycling are presented.Materials and methods. The research and testing equipment with high reproducibility of results is used. Properties of manufactured specimens of materials were determined by standard methods. Methods of X-ray phase analysis, optical and scanning electron microscopy were used to study the structure of materials.Results. Compositions of composite materials with density from 1,750 to 2,000 kg/m3 and compressive strength from 20 to 40 MPa have been developed. Compositions included Portland cement, waste of cross-linked polyethylene and ceramic bricks, polycarboxylate plasticizer, silica filler and calcium chloride solution. The possibility of using floured broken brick as a partial replacement of cement and crushed cross-linked polyethylene as an aggregate is investigated. The microstructure of the obtained composite materials was studied and it was concluded that cross-linked polyethylene aggregate is reinforce a homogeneous matrix, which is a product of the interaction of cement, brick powder and silica filler. During the hardening of matrix strong crystal structure consisting of hydrosilicates and calcium and quartz carbonates is formed.Conclusions. The obtained results can be used in the production of building composite materials based on recycling of ceramic brick waste and cross-linked polyethylene. Due to the fact that the cost of the presented waste is much lower than the cost of Portland cement and traditional aggregates (by about 25 %), and their recycling is accompanied by the reduction of negative impact on the environment, composites based on them have good prospects for implementation in construction practice.

Introduction. Thermal insulation materials, including foam glass, are used to reduce heat losses in buildings. Foam glass has low thermal conductivity, high strength and environmental safety. Researches of scientists, including I.I. Kitaygorodsky and B.K. Demidovich, are aimed at controlling the process of foam glass synthesis and regulating the crystallization process. The cost reduction of foam glass is possible through the utilization of industrial waste.Materials and methods. The potential for reusing and obtaining foam glass is being studied using ash and slag waste from a power station in the Rostov region. The study of foam glass batch mixture includes preparation of raw materials, molding and firing. The research of the structure was conducted using an automatic diffractometer, micro-tomograph, and scanning electron microscope. Tests were carried out to assess the properties of foam glass specimens, such as thermal conducti-vity, strength, density, and load impact. The composition of raw materials for foam glass include broken glass, ash and slag mixture and Na2B4O7·10H2O. Foam glass synthesis was performed using anthracite, zirconium dioxide, chromium oxide, and magnesium oxide.Results. The research revealed the formation of crystalline phases in the amorphous foam glass framework. The presence of quartz, pyroxene, cristobalite, eskolaite, and wollastonite in foam glass composition was confirmed.Conclusions. Batch compositions and synthesis parameters were developed, leading to the production of nine modifications of foam glass with uniform porous structure and varying content of crystalline phases. Crystalline inclusions are evenly distributed. The role of crystallization centres is played by the crystalline phases present in the raw materials (in the composition of ash-and-slag mixture) and additional crystallization initiators (chromium oxide, zirconium dioxide and magnesium oxide). The conformity of foam glass properties to standard requirements was demonstrated.

Introduction. In the current climate change conditions, the protection of irrigation structures, especially dams, is a very important task. Seepage is one of the main causes of dam failure, so it is very important to investigate the seepage regimes and find solutions to prevent dam failures as a result of the seepage processes in earth dams. In this paper, the analysis of the seepage regimes in the body of earth dams is performed by means of mathematical modelling using numerical finite element models. A homogeneous earth dam with an imperfect diaphragm on an impermeable foundation is taken as the object of study. The purpose of the study is to determine the influence of relative parameters: diaphragm height, diaphragm location in the dam body, their number. In addition, the influence of diaphragm parameters on the seepage flow through the dam body and its velocity is analyzed.Materials and methods. The study was carried out with the help of numerical modelling using PLAXIS 2D software. The model of the dam is based on typical design solutions used in practice.Results. The results of the study show that the placement of the diaphragm in the dam body reduces the seepage flow through the dam and the height of the diaphragm is inversely proportional to the seepage rate. The maximum seepage rate was recorded at the upper end of the diaphragm and its magnitude is directly proportional to the height of the diaphragm. When the diaphragm is displaced towards the downstream side, the filtration rate slightly decreases. The value of maximum velocity increases when the diaphragm is displaced towards the downstream end.Conclusions. Dam failure due to seepage can result in serious property damage and loss of life. Implementing methods that reduce seepage discharge and seepage velocities is important to ensure safe dam operating conditions

Introduction. The formation of an effective organizational structure of construction production management at the corporate level implies adaptation to new conditions. However, in this process, there is a problem of a gap (differentiation) of the plan and action, which requires corrective actions, including with regard to the organizational structure and management processes (business processes) of investment and construction activities. In the future, such impacts will determine the nature of reengineering activities in this area. Business process reengineering and organizational structure reengineering are considered. There is a certain dependence between these types of qualitative organizational transformations, which is primarily due to the transience of the modern life cycle of engineering solutions. Thus, it is possible to identify the purpose of the research — it is a scientific justification for the improvement of the corporate regulation system through reengineering of the organizational structure and business processes of investment and construction activities. On this basis, it is possible to formulate the objectives of the research: to establish the regularity of the gap (differentiation) of the plan and action in the system of corporate governance, to identify the dependence of business processes and organizational structure of investment and construction activities in the context of reengineering of business processes and organizational structure in construction. The object of the research is the system of corporate regulation of investment and construction activities, and the subject is the organizational structure and business processes in construction. From the point of view of practical value, these types of reengineering allow an economic entity to improve the quality and efficiency of construction products by focusing production activities on the consumer and a process approach in management. On this basis it will help to gain competitive advantages, among other things through the wider use of technical means, employees meeting higher requirements of scientific and technical progress and capable of solving complex problems of investment and construction activities, arising at the present stage, in the shortest possible time.Materials and methods. The theoretical basis of the research was a system approach, logistics of regulatory impacts, structural and functional analysis, methods of investment design, strategic and operational management. The information base of the research was the scientific search carried out by the authors earlier, which was reflected in published papers on this subject. Additional sources were scientific works of domestic and foreign scientists, as well as practical materials.Results. The solution of the gap (differentiation) problem in investment and construction activities is shown, which made it possible to propose a scheme of regulation of a construction company, to establish dependencies of business processes and organizational structure of investment and construction activities, as well as dependencies of business process reengineering and organizational structure reengineering in construction.Conclusions. The gap (differentiation) between the plan and the action of a construction organization is caused by fluctuations in the external environment. The main tool for effective adaptation to external fluctuations and corporate regulation is a qualitative transformation of business processes and organizational structure, i.e. their reengineering.

Introduction. The authors of the paper studied the issue of competition in the modern Russian market of the residential real estate. A little-studied aspect — the choice of the lexical means and forms contributing to better sales — is studied.Materials and methods. Works of domestic and foreign authors, as well as the content from official websites, prospects, outdoor advertizing and information from some of the largest developers operating in Moscow and Moscow region were considered as the materials of the research. The authors used such methods as observation, description, poll, quantitative statistical analysis, comparative analysis, structural analysis, semantic-stylistic analysis, frequency analysis, etc.Results. The authors studied the influence of language image on pricing and popularity among buyers in the market of the residential real estate. The analysis of offers of the largest developers operating in Moscow and Moscow region confirmed the assumption that the best sales, as well as the formation of higher prices, are promoted by the use of foreign words in the names of housing estates, foreign loan words to denote rooms and spaces (“lounge zone”, “play-hub”, co-working), epithets like “club house”, etc.Conclusions. As the result of the conducted research, the authors made the conclusion, that language images in names, in the description and advertizing of housing estates are an effective instrument to increase their competitiveness, better market promotion and profitable sales at higher prices. The idea that there is also a downside to this phenomenon and it is put forward as a debatable point: the language image, which forms an image of the housing estate as elite, closed, accessible only to a narrow circle of residents, and at the same time self-sufficient, providing them not only with housing, but also with a wide range of social and domestic services and even business space, leads to isolation and some kind of enclave in such complexes. Nowadays there is an a desocialization of the residents of housing estates, spreading a lifestyle that does not involve unnecessary contacts in the “outside world”, and in fact, that means the formation of a new paradigm in housing construction and a new urban philosophy.