Introduction. The paper reflects an important problem related to the development of industrial potential of Syrian cities. Taking into account the geographical location of the country in hot climate conditions, it is proposed to widely use renewable sources of solar energy, using highly efficient energy-generating devices in the form of parabolic solar concentrators. The results of research on the formation of energy-efficient industrial buildings with the integration of solar concentrators in their structure, systematically placed in the upper space of buildings above the roof, are presented.

Materials and methods. The fundamental possibility of using energy-generating solar concentrators is illustrated in the paper based on a variant analysis of possible methods of constructive placement and orientation of energy modules for various types of industrial buildings. New solutions are shown both for conditions of structurally independent support of external energy module systems and for conditions of their partial or complete support on the frame structures of an industrial building.

Results. The recommended new solutions provide energy autonomy of the enterprise, the possibility of flexible, compact and independent placement of energy-generating devices in the conditions of the existing industrial development, as well as in the conditions of improvement and modernization of industrial buildings.

Conclusions. The proposed solutions for the formation of new energy-efficient types of industrial buildings based on the active use of solar energy are recommended for wide practical application, which will provide conditions for the sustainable development of industrial centres in the cities of Syria.

Introduction. Creation of a comfortable environment in Russian cities sets a task to reconstruct the street and road network and transform the street space from a transit zone into a public space. Such transition is impossible without taking into account the needs of all street space users and creating the appropriate infrastructure for them. The current regulatory framework does not take into account the heterogeneous nature of street use within one urban development category, which leads to absence of objective parameters for creation of such infrastructure on different sections of the street.

Materials and methods. The authors used data from open sources, statistical and graphic data from municipal institutions, and data from field surveys. In order to determine the values of the parameters that determine the pattern of use of a street section, cluster analysis was applied separately for each user: pedestrians, individual mobility vehicles, and public transport.

Results. Cluster analysis allowed to determine the set of factors that determine the pattern of use of a street section by pedestrians, individual mobility vehicles and public transport. Considering the pattern of use allowed to identify the scope of measures required for creation of infrastructure on each specific street section.

Conclusions. The proposed methodology for determining the importance of a user on a street section allows to objectively assess the need to place certain elements in the cross-section of streets during reconstruction. The analysis of the urban planning conditions in which street sections are located, such as the position in the city plan, the presence and characteristics of the adjacent development, which forms the flow of traffic, pedestrians and means of individual mobility and determines the presence of centres of gravity or exclusively transit function of the section, will allow to formulate a set of design recommendations in the conditions of new construction.

Introduction. Experimental research projects of full-scale building roof constructions are labour-intensive, high-cost, and do not require placement in laboratories due to their large size. In this regard, tests of building constructions are often carried out on scale models. The operation of combined arch systems is poorly studied; calculation models of such systems require experimental confirmation. The presented experimental research project is aimed at obtaining data on the actual operation of the arch and a combined arch structure with radial ties for subsequent comparison of experimental data with calculation models.

Materials and methods. The experimental model is developed using mixed similarity at a scale of 1:10. The physical and mechanical parameters of the model materials were determined using standard methods. A method for creating a given prestress in the arch ties and a method for testing it are developed and described. The calculation models are implemented in the LIRA-SAPR finite element software package, considering the geometrically nonlinear structure operation, the stresses in the arch sections are determined using the “Section Designer” processor.

Results. Based on the results of experimental studies and numerical calculations, stresses and displacements in arch sections were obtained. The movements of the circuit, graphs of correspondence between experimental data and calculation results are shown. Directions for improving experimental models of such combined systems with ties are analyzed.

Conclusions. An arch combined system with radial ties allows to equalize the stress values in the arch belt in comparison with an arch without ties. The maximum stresses in the arch sections and the maximum deflections in the middle of the arch span are reduced by 3 times when tightening is installed.

Introduction. Stress loss of polymer-composite reinforcement in prestressed concrete is one of the main problems affecting their crack resistance and stiffness. However, to date this issue has not been sufficiently studied. The paper proposes methods for determining losses from relaxation of fibreglass reinforcement, and also provides experimental studies of stress losses in fibreglass reinforcement at different levels of initial tension. The results of the study show the nature of the reduction in forces in fibreglass rods, and the dependences of stress loss over time are also proposed.

Materials and methods. The results of the analysis and systematic synthesis of data obtained from domestic and foreign sources on the issues of force loss in prestressed composite rods from relaxation and creep are used as a basis. Based on the results of experimental data, logarithmic dependences of voltage losses over time are proposed.

Results. As a result of the experiment, it was possible to record the nature of the change in forces in prestressed fibreglass rods. A logarithmic dependence is well suited to describe the relaxation component of stress losses in a fibreglass rod over time.

Conclusions. The study of stress losses in fibreglass reinforcement during relaxation and creep showed that stress losses are most pronounced in the first days after tensioning the reinforcement, with a subsequent decrease in the rate of losses over time. Relaxation losses in fibreglass reinforcement were quantitatively determined based on the experiments conducted, which confirmed that the logarithmic dependence describes well the nature of stress losses in the material. The scientific novelty of the study lies in obtaining experimental data on the relaxation of reinforcement made of domestic fibreglass, which complements existing knowledge and allows us to clarify regulatory documents, such as CP 295.1325800.2017. The practical significance of the work lies in the fact that the results obtained allow us to predict the durability and performance characteristics of structures using fibreglass reinforcement, as well as make adjustments to existing engineering solutions to minimize stress losses. Recommendations for practice include the need for further research to refine the relaxation factors as a function of initial stress and to develop more accurate calculation methods for engineering applications.

Introduction. For some elastic systems with a finite number of degrees of freedom of masses, in which the directions of mass movement are parallel, methods of creating additional connections were developed, the introduction of each of which purposefully increases the value of only one natural frequency to a given value, while not changing any of the other natural frequencies and not one of the natural modes (forms of natural oscillations). If it is necessary to increase the values of several natural frequencies in a targeted manner, then this requirement can be implemented by creating an appropriate number of separate targeted connections. The computational scheme of each of the individual targeted connections should include racks installed at the nodes of mass application and directed along the trajectory of their movement. In some cases, individual targeted connections can be independently installed on the original (initial) system. In most cases, on the basis of individual targeted connections, a computational scheme of a united group targeted connection is developed, which increases all the intended frequencies to the set values, without changing any of the other natural frequencies and not one of the natural modes. Calculation examples are presented.

Materials and methods. Methods of targeted control of the frequency spectrum of natural oscillations of elastic systems are used in the paper. These methods, which are based on the introduction of additional connections, were proposed and developed in the works of L.S. Lyakhovich. For verification purposes, the finite element method (FEM) and the corresponding software are also used.

Results. A method of forming a matrix of additional stiffness, which corresponds to a group targeted connection is proposed. The requirements for those targeted connections, on the basis of which a group targeted connection is formed, are formulated. An algorithm for the development of a group targeted connection is proposed with allowance for the formulated requirements. Verification of the proposed algorithm for the development of a group targeted connection is done with the use of SCAD and Lira Software products.

Conclusions. The results of the work can be used by research and design organizations, as well as in higher education institutions in the preparation of special courses for construction specialties (areas of training).

Introduction. An increase in the transport load on highways due to the growth of freight transportation by road and shift of business activity in the Urals, Siberia and the Far East require ensuring satisfactory inter-repair terms of road surfaces in harsh natural and climatic conditions. At the same time, a systematic increase in the depth of oil refining leads to a decrease in the content of marginal low molecular weight hydrocarbons in the composition of oxidized petroleum bitumen, which are widely used in our country. Therefore, the task of increasing the low-temperature characteristics of bitumen and modified binders based on it is becoming more and more urgent. Promising in many respects is the use of by-products of wood processing and forestry chemistry for the above purposes, the production of which is concentrated mainly in regions where frost-resistant bitumen grades are required.

Materials and methods. As the materials under study, we considered the traditional Russian bitumen oil road oxidized grades BND 70/100 and specimens of tall pitch, which is produced in large quantities during wood processing at a number of domestic enterprises. Methods of differential scanning calorimetry and thermogravimetric analysis were used to determine the physico-mechanical characteristics specific to the studied specimens.

Results. The paper presents the results of comprehensive studies of the possibility of using plant plasticizers — products of wood processing and forestry chemistry as regulators of the physico-mechanical properties of complex road binders, thermogravimetric analysis of the component composition of bitumen, as well as commercial products of wood processing.

Conclusions. The recommendations developed on the basis of a set of practical studies allow us to predict an improvement in the performance of mixed binders when their physico-chemical composition changes at the stage of preparation for the production of asphalt concrete mixtures.

Introduction. In construction, a large number of objects are erected in conditions where the foundation consists of carbonate rocks that are destroyed to the state of powder. The paper provides materials on the planning, preparation and conduct of a laboratory experimental test for dolomite powder lying at the base of a building in the Kazan. The experiment is presented to quantify the suffusion resistance of powder.

Materials and methods. The study of the suffusion resistance of dolomite powder was carried out using a special filtration-suffusion device. When planning and preparing the experiment, all the main factors were simultaneously taken into account. For mechanical suffusion, these are the physical and filtration characteristics of the rock, its stress-strain state (SSS) and also the volume of the receiving zone for the suffusion products carried out by the filtration flow. For chemical suffusion these are the chemical composition and condition of the rock, the chemical composition and speed of water movement.

Results. It was established that dolomite powder is not subject to the dissolution process, therefore it is classified as eluvial soil and not as karst rock. In terms of mechanical suffusion stability, a comparison was made of the results of analytical solutions and experimental tests, according to which in the first case the dolomite powder is suffusion, and in the second — practically non-suffusion.

Conclusions. The construction site is classified as non-hazardous in terms of karst and karst-suffusion. At the same time, mechanical suffusion not related to karst cannot be excluded. When assessing the suffusion resistance of dolomite powder, it is recommended to use the rate of mechanical or complex (chemical-mechanical) suffusion instead of the rate of rock dissolution. In the future it is recommended to use the obtained value when predicting the size of suffusion deformations.

Introduction. The importance of using composite modelling in the design of wave loads and impacts on port hydraulic structures, namely determining the parameters of design waves, is pointed out. The regulatory documents intended to calculate the permissible values of wave elements for the safe servicing of ships at the berth, some shortcomings are noted, some of which are described in this paper.

Materials and methods. Two objects are used as examples: the Western transport and logistics hub, designed in the Kola Bay of the Barents Sea (where the SWAN wind wave model and the COASTOX-CUR model of currents and water levels were used for numerical modelling, calculations by the analytical method were performed according to SR 38.13330.2018) and the Multifunctional Cargo Area located in the Terpeniya Bay of the Sea of Okhotsk (where calculations were carried out in the SWAN wind wave model and the SWASH long-wave model). For the first case, wave values at control points were used. In the second case, two calculation models were used to determine the influence of the vessel on the wave field — simplified and numerical ones.

Results. For the first example, the differences in the values of waves with and without reflection were analyzed using the analytical method. For the second, the modelling results are presented — the field of significant wave heights for a simplified wall with and without a vessel with a table of control point values. Modelling of a vessel in a mooring pocket is shown through pictures of instantaneous marks of the rough surface and the field of significant heights with the output of control point values. An analysis of the obtained height values in paintings with and without a vessel was performed.

Conclusions. Analysis of two problems showed that the determination of acceptable wave elements at the berth for the safe servicing of ships, carried out in accordance with current regulatory documents, can lead to contradictions, namely the initial data for calculations and a significant change in the wave fields of the port water area when the wave interacts with the moored vessel. As a consequence, this affects the final conclusion about the safe interaction of ships with berth structures.

Introduction. In modern design practice, it is customary to calculate the cooling capacity of an air-conditioning system as the sum of the maximum heat inputs into the room from the individual sources. The indoor air temperature in such calculations is assumed to be equal to the required temperature according to the hygienic norms. In this case, the calculation itself is performed with consideration of stationary heat transfer.

Materials and methods. The 24-hour thermal conditions of a dwelling room in Moscow with a window facing east were calculated. The calculation results were compared for steady-state and non-steady-state thermal conditions. Temperature maintenance in the room was achieved by night ventilation with outside air and daytime cooling with air from the Split-system, as well as by the cooling system with supply air. The chilled air temperature was assumed to be 20 and 22 °C.

Results. The changes during the day in indoor air temperature in a room oriented to the east were determined. It was found out that at a maximum daily outdoor air temperature of 33 °C, maintaining indoor air temperature not higher than 24 °C is possible only if the room is cooled with supply air of 22 °C and below 24 hours a day. It is also possible to cool the room starting at 5:45 a.m. with supply air cooled to 20 °C. In this case, the solar heat transmittance coefficient of the window should be no higher than 0.5.

Conclusions. Since in recent years there are higher outdoor air temperatures than before, it is advisable to increase the design outdoor air temperature during the warm period of the year.

Introduction. Digital technologies are one of the drivers of the development of all spheres of activity, in particular the construction industry. Digitalization has a qualitative impact on the activities of construction industry enterprises, while the technologies introduced significantly affect business models. The lack of comprehensive studies aimed at studying the degree of change in the business models of construction industry enterprises determined the relevance of this work, the purpose of which is a comprehensive representation of how the business models of construction industry enterprises will be changed under the influence of digital technologies.

Materials and methods. The paper provides a comprehensive analysis of changes in business models of construction industry enterprises under the influence of the digitalization process. The analysis took into account the scientific works of domestic and foreign researchers, and also used cases of Russian construction industry enterprises. The changes in all four business areas are considered in detail: customer experience, offering, infrastructure and company financial performance; the changes in nine blocks of business models are also described in detail: key partners, key activities, key resources, value proposition, customer relations, sales channels, consumer segment, cost structure and income streams.

Results. A general scheme of changing the business model of construction industry enterprises under the influence of digital economy technologies is presented: a typical business model of construction industry enterprises before the digital transformation process and a business model with characteristic changes that will occur under the influence of digital transformation are presented.

Conclusions. During the study, a comprehensive analysis of the impact of digital technologies on the business models of construction industry enterprises was carried out, and a unified representation of the digital transformation of business models of construction industry enterprises was formed. The results of this study can be used and implemented in practical activities of construction industry enterprises engaged in digitalization of their activities in terms of making relevant changes to the existing business models of such enterprises.

Introduction. The complexity and ambition of the tasks currently being solved by the construction industry indicate the need for a new interpretation of their formulation, especially with regard to ensuring scientific leadership and technological sovereignty. In this logic, it is possible to consider an industrial scientific and production complex as a system with a dissipative organizational structure. In this regard, the paper provides a definition of dissipative organizational structures, their properties and place in the organizational and economic mechanism of management of an industrial scientific and industrial complex are indicated. The conducted research made it possible to show the prospects for the use of dissipative structures in the construction management system, to formulate recommendations on their formation and functioning.

Materials and methods. The solution of the research tasks involves a systematic approach to the management of industrial scientific and industrial complexes, the use of life cycle theories, logistics of regulatory influences, as well as methods of structural and functional analysis, deduction and induction. The methodological basis, in addition to these research tools, is the scientific foundation formed by domestic and foreign scientists on this issue.

Results. The features of the formation and functioning of management systems of industrial scientific and industrial complexes are established, dissipative organizational structures are terminologically identified, their properties are determined, as well as the possibilities of use in the system of an industrial scientific and industrial complex, the basic provisions of the organizational and economic mechanism of functioning of such complexes based on dissipative structures for which the effectiveness of application is determined, the prospects for the use of dissipative structures in the construction management system, recommendations on their formation and functioning are formulated.

Conclusions. An industrial scientific and production complex can be considered as a system with a dissipative organizational structure. In this case, the main focus of management is not to find the balance of the system, but to ensure development largely due to its self–organization. Such a presentation of the industrial scientific and production complex will contribute to improving its effectiveness.