The article presents the results of a study of the use of reinforcement in glued wooden elements of a circular mesh vault. The use of reinforcement in flat wooden structures has proven itself well, but the possibility of using reinforcement in large-span spatial structures still remains little explored. A number of authors presented conflicting data regarding the increase in the bearing capacity and rigidity of reinforced wooden glued elements. In the proposed work, a numerical experiment was performed to compare various options for reinforcing elements of a circular mesh vault. 10 options for external and internal reinforcement of elements with various materials were considered. As a result of the analysis of the stress distribution in the section of the elements, it was revealed that external reinforcement is a more priority method of reinforcement in terms of the stress-strain state of the element. The dependences of the deflection on the height of the section and the area of the reinforcement were determined. The most appropriate solution in terms of material consumption, economic efficiency and corrosion resistance is internal reinforcement with carbon composite reinforcement.

Keywords: Circular mesh vault, glued timber, wood reinforcement, FRP, external reinforcement, numerical stress analysis, economic efficiency of reinforcement

When solving the problem of ensuring the mechanical safety of buildings and structures according to GOST 27551-2014 “Reliability of building structures and foundations. Basic provisions” it is allowed to apply a risk-oriented approach. A mandatory stage of this approach is the forecast of the expected accident risk situation of the facility. Due to the fact that the current regulatory documents on risks do not reflect all the features of the stress-strain state of building structures and foundations of buildings and structures during the operation of structures and, therefore, do not allow for a sufficiently accurate assessment of the safety of structural systems, risk assessment for building structures is a very relevant scientific and technical problem.

Keywords: building, building structures, design, destruction, safety, accident risk, risk assessment, risk management, monitoring and risk analysis

The article deals with the application of load-bearing and enclosing structures made of glued wood for multi-storey, including residential, buildings. Introduction. The relevance of the construction of wooden multi-storey buildings is confirmed by quite a large experience of construction abroad. Also, there is an increasing interest in this industry in Russia at present. Theoretical numerical study and technical and economic evaluation of the results. The stress-strain state and technical and economic indicators of three structural schemes of the building are analysed in the proposed work on the basis of the theoretical study: frame scheme - full frame with bearing columns, floor and roof beams; combined structural scheme - vertical bearing elements are wooden columns, glued wooden panel is used as floor and roof; frameless structural scheme - all the structural elements are made of glued wooden panels. Conclusions. As a result, the most rational and economically favourable structural solution of a multi-storey building made of glued wooden elements has been obtained.

Keywords: glued timber structures, wooden multi-storey building, structural design, economic efficiency, stress-strain state

This work is a continuation of a scientific study to determine the effectiveness of composite materials based on carbon fabric in the field of strengthening bending and compressed elements. The article is devoted to the determination of the geometric characteristics of prototypes, the description of the structure of the internal metal frame and the methodology for strengthening reinforced concrete samples. The importance of this scientific work lies in the fact that one of the most popular companies selling composite materials in Russia (“Gidrozo”) proposes to use a new technology for reinforcing reinforced concrete structures that differs from that recommended in the norms. However, according to the manufacturer's specialists, this technique not only ensures reliable adhesion and joint operation of reinforcement materials and structural concrete, but also significantly increases the efficiency of the composite material.

Keywords: steel, heavy concrete, reinforced concrete, composite material, reinforcement, carbon fiber, test, stand, beam, sample

No modern metropolis can be imagined without such public transport as the subway. The subway is the most important element of infrastructure for large cities and provides a convenient, fast, safe and environmentally friendly way for the population to travel. The construction of the subway is a long and complex process, which requires large investments and consideration of many factors. During the construction of metro stations it is necessary to carry out work on laying utilities, such as electric cables, pipelines for water supply, sewerage, ventilation and other systems. These utilities ensure the operation of the stations and comfort for passengers. Erection of engineering networks in the subway is a complex and multi-year process that requires application of new technologies and high qualification of specialists. However, proper planning and work coordination can significantly reduce time and costs of the project, ensuring uninterrupted operation of metro stations in the future. The work is devoted to the peculiarities of construction of the Moscow subway, which is considered one of the largest subways in the world in terms of length and passenger traffic.

Keywords: metro, utilities, high voltage cable, ventilation shaft, tunnel fan

This article presents the main recommendations for the construction of nodes of solid-wood structures. The basic scheme of the rigid junction of the meridional edges is considered. Based on the results of tests and calculations, conclusions are drawn on the possibility of improving this node. Some recommendations for strengthening the node without increasing the metal capacity of the structure are presented. Several schemes for improving the welded structures are shown. Conclusions are drawn on the possibility of implementing the examples given in the designed structures.

Keywords: Wooden structure, full-size samples, mechanical connections, solid wood, prismatic arch, mounting element, polymer concrete, design model, continuous girder, prefabricated structures

The influence of the location of reinforcing bonds on the general condition of cylindrical mesh shells is investigated. Cruciform core elements made of tubular profiles were used as reinforcing structures. The number of reinforcing elements is 8 (4 on each panel). Opposite nodes of adjacent faces are connected by cross-shaped elements in the direction of the arc. The expediency of placing reinforcement elements inside each of the two middle panels and at a distance of one panel from the middle of the length is checked. As a result of the conducted studies, the regularities of the stress-strain state and dangerous areas of the shell were determined. When using cruciform joints, a decrease in the forces in the elements and a decrease in the movements of the nodes were revealed. A redistribution of internal force factors and a decrease in the number of typical sizes of elements were recorded. A rational scheme of reinforcement of the structure is obtained.

Keywords: cylindrical mesh shell, reinforcement, cross-shaped elements, forces, displacements

The results of studies of two-layer reinforced concrete beams with a layer of various thicknesses of high-modulus concrete of the frame structure in the compressed zone and traditional heavy concrete in the rest of the section are presented. The stress-strain state of normal cross sections along the height of the beam was estimated by the values of relative deformations at the level of stretched and compressed reinforcement using the hypothesis of flat sections and actual compression and calculated tensile deformation diagrams of concrete. The influence of the thickness of a layer of high-modulus concrete on the nature of the stress-strain state between the layers is shown. The possibility of destruction of the beam on the concrete of the compressed zone was revealed due to the abrupt decrease in the actual height of the compressed zone due to the "shooting" of a layer of high-modulus concrete with its thickness less than 0.1 h0. The dependence of the relative actual thickness of the compressed concrete, i.e. the distance from the edge fiber of the compressed concrete to the neutral axis, in the studied beams on the magnitude of the bending moment is obtained. It is established that for single-layer beams, with a difference in the elastic modulus of concrete up to 20%, the dependences of the relative actual thickness of the compressed concrete layer on the bending moment are almost identical. In the studied beams, the limiting state of which is caused by the fluidity of the reinforcement, the thickness of the compressed concrete layer was 0.37 ...0.4 with a relative moment value of 0.5, and 0.33 ...0.36 with a maximum bending moment value.

Keywords: double-layer reinforced concrete beams, normal cross-sections, nonlinear deformation model, high-modulus concrete, neutral axis coordinate

The article describes the conduct of field studies carried out during the overhaul of the cultural heritage object – the building of MBOU "Gymnasium No. 45" to establish rational parameters of injection of cement-sand mortar, the choice of the type and design of injectors and the scheme of drilling injection wells. It is proved that the technical solutions adopted in the soil fixing project are not optimal and do not provide the required quality of work. Recommendations on technological and constructive solutions for fixing soils have been developed and implemented in practice, taking into account engineering and geological conditions, the results of the survey and fixing at the pilot site.

Keywords: subsidence soil, foundation, cementation, injector, well drilling, geocomposite

The features of the functioning of steel structures in an aggressive environment are considered, the results of a qualitative and quantitative assessment of the nature of damage to a profiled sheet are given.

Keywords: steel structures, building structures, corrosion, aggressive environment, zinc coating, corrosion rate

The technical solution for the construction of local treatment of return drainage flow from an irrigated area, based on the use of ion-exchange filter materials, is proposed. It has been established that the concentration of chemicals in the water of the drainage well is 1/3 lower than in the open collector, where the drainage flow is diverted. Therefore, the localization of the technological unit for the treatment of drainage water relative to the drainage well is a reasonable decision, since it will reduce the financial costs of filter media and the frequency of their replacement. The technological scheme of the treatment plant based on the block principle is described: by disconnecting or connecting individual blocks, it is possible to respond flexibly to changing needs in the quality and degree of drainage water treatment.

Keywords: technical solution, water treatment, ion exchange, drainage flow, block approach, drainage well, water quality, chemical analysis, land reclamation, irrigation system

The thickness of the steel sheets used in the element was gradually increased to meet the load bearing capacity requirements of large span steel bridges. As the main method of joining heavy plate steel, welding results in significant residual welding stresses with a complex distribution. Large residual stress during welding will significantly affect the performance of steel bridges. In this work, the distribution of residual stress in a welded thick steel sheet is systematically investigated, a specimen with a thickness of 80 mm was designed and manufactured, and the residual stress of welding was measured by X-ray diffraction.

Keywords: steel bridge, thick steel plate, welding residual stresses, X-ray diffraction method, weld joint

The article considers a comparative analysis of the methods of accounting for the influence of heavy-duty transport on the durability of road surfaces. The methods of calculating the coefficients of reduction to the design load are analyzed in detail. The modulus of elasticity is calculated according to the method of ODN 218.046-01 using reduction coefficients according to calculations of different methods. Recommendations on the application of the most effective technical solutions in the design of highways are given.

Keywords: automobile road, pavement, modulus of elasticity, heavy-duty transport

The article presents the result of a retrospective historical analysis of the architectural and urban planning concept for the restoration of the residential area of the Stalingrad Tractor Plant, developed after the end of the Battle of Stalingrad. The basic principles of organizing the planning of the living environment and the architectural and figurative solution of the building are revealed. The main compositional techniques and semiotic knots, which are the basis for the modern development of the Traktorozavodsky district of Volgograd, are singled out. Techniques and approaches to the landscape organization of the urban environment are studied.

Keywords: urban planning, historical analysis of territories, reconstruction, semiotics of the city, cultural heritage, soviet architecture

In this article, the stress state of a wooden beam reinforced with polymer composite reinforcement made of carbon tape of various lengths is investigated. The minimum required length of a carbon fabric-based reinforcing tape is determined in the most loaded lower stretched zone of a single-span solid-wood beam.

Keywords: solid-wood beam, polymer composite construction, carbon fabric tape, physical and mechanical characteristics of the composite, design load, place of breakage of the reinforcing tape, stress state of the beam, stress concentration zone

The article should choose a metal truss based on the initial data for pitched roofs. Defined maximum loads and deflections in each truss. On the analysis of the residually deformed state of the truss, it was concluded that the most authentic in terms of the structural members of the truss. Recommendations are given for the design of load-bearing structures of roofs on metal trusses in the manufacture of a shed roof structure.

Keywords: truss, effort, designing, deflection, roof, load, static calculation, displacements, trapezoidal truss, Molodechno truss

The main maintenance of a diversification of production as activity of subjects of managing is considered. being shown in purchase of the operating enterprises, the organizations of the new enterprises, redistribution of investments in interests of the organization and development of new production on available floor spaces. The most important organizational economic targets of a diversification of management are presented by innovative activity of the industrial enterprise.

Keywords: wastewater, dephosphatation, acidification, nutrient removal

Building objects experience various kinds of impacts that can cause deformations of structural elements - deflections, integrity violations, complete destruction of individual elements, etc. Timely detection of deformations and monitoring of their dynamics is the most important element of the safe operation of buildings and structures. The task of monitoring cracks in building structures is to record changes in cracks in order to monitor their technical condition. As a result of monitoring, decisions are made on the further operation of the facility, the need for repair measures, and the elimination of factors affecting the development of cracks. The use of beacons makes it possible to monitor the behavior of deformations of building structures. For the simplest observations, gypsum and point beacons can be used, for more detailed observations, clock-type beacons and plate beacons can be used. Electronic beacons enable detailed automated monitoring of changes.

Keywords: crack, beacon, gypsum beacon, lamellar beacon, sentry beacon, point beacon, crack opening width

Building information modeling (BIM) creates new opportunities not only in design and construction life cycle's phases, but also in operation of buildings. One of the most promising fields is historical building information modeling (HBIM). In the article areas of BIM's application during inspection and monitoring of timber strutures of historical buildings are outlined. Creation of 3D model of objects with complex geometry and structures with variable cross-sections is described. Questions of early warning system's creation during structural health monitoring (SHM) of buildings are considered. Works of domestic and international authors are analyzed. Areas that deserve further investigation are determined. They include integration of BIM with geographic information systems (GIS) and non-destructive testing (NDT) methods, creation of database of defects of buildings and structures.

Keywords: architectural monument, BIM, defect, early warning, HBIM, inspection of buildings, NDT, SHM, technical condition, timber structure

Constant force supports are used in all gas and oil refineries in cases where it is necessary to provide the mobility of the pipeline at the attachment points. The article discusses the algorithm for calculating the shape of the support profile details, which has a certain design. These details provide the constancy of the pipeline support vertical force when it is transferred from the compression spring to the support point. Analytical and geometrical variations of calculation are given. The article will be useful to specialists involved in the design of pipeline supports.

Keywords: movable joint, geometric calculation, variable stiffness, lisega, import substitution

In connection with improvement of public welfare, coming to the fore are requirements enabling comfortable living, which primarily depends on conditions of indoor air environment. This article provides arguments to suggest that, during reconstruction and overhaul of residential buildings, natural ventilation systems, failing to provide the required air exchange, need to be replaced with hybrid ventilation systems, allowing to maintain stable ventilation in existing multi-storey buildings throughout the year and involving minor capital and operating costs. Based on the example of a typical nine-storey residential building, two variations of hybrid ventilation have been developed: containing an ejector and roof fans, with economic feasibility of using both determined.

Keywords: microclimate quality, air exchange, natural ventilation, hybrid ventilation, an ejector, a roof fan, economic feasibility

The article presents the results of theoretical and experimental scientific research on the problem of monitoring the safety of a coal-mining region at the stage of closing unpromising mines. To achieve the goal of research - the formation of an effective methodology for this problem - the following main tasks have been solved: - assessment of the negative impact of mining operations on the technosphere of the region; - selection of the basic characteristics of the natural-technogenic system; - comparative analysis of methods and technical and technological systems for environmental control. The authors of the article formulated the concept of a safe region and the hypothesis of its implementation. In particular, scientific and methodological approaches have been developed that provide an objective assessment of the results of research and the adoption of managerial decisions on the formation of a safe environment for the life of the population. The article shows that the effectiveness of the developed methodology in specific conditions is 85-90%.

Keywords: coal mining region, liquidation of mines, coal rock massif, methodology, natural-technogenic system, safety concept, proactive monitoring

The paper considers an example of solving a plane problem of the theory of plasticity as applied to concrete, which occurs when an absolutely rigid stamp acts on a concrete base. In this case, the solution was sought in the form of isolines of characteristics, the position of which made it possible to determine the stress state of the foundation. In this case, three areas were distinguished, differing in the stressed state. In the work, it was possible to analyze the effect of friction on the surface of the stamp on the boundaries of these regions and the isolines of stresses in them. Three conditions were considered: friction is absent, friction is constant, friction is proportional to the greater principal stress. The influence of various boundary conditions on the surface of the stamp on the stress state of the concrete base is revealed.

Keywords: concrete, theory of plasticity, plane problem, stress-strain state, stresses, friction, corner punch

In the field of design and construction of transport facilities, in particular railway transport, Industry 4.0 technologies are gradually being used. In the transport industry, the concept of "digital twins" - a computer representation of a real object - has become especially widespread. The basis for "digital twins" are information models (TIM-models). At the present stage of the development of these technologies, the method of applying TIM for linear-broaching objects has not been worked out to the end. This paper considers the experience of designing railway infrastructure facilities using information modeling technologies in Russia and in the world. The concept of the methodology for the practical implementation of information modeling technology for railway infrastructure facilities at the design stage is proposed. The main limitations of the presented methodology and ways to overcome them are considered.

Keywords: BIM, information model, railways, railway information modeling technologies, information modeling methodology

The possibility and expediency of switching from qualitative regulation of heat supply to quantitative in centralized heat supply systems for the existing network from the district boiler house No. 1364 of Volgograd is substantiated. The main advantages and disadvantages of each method of regulating heat supply to consumers are considered. The basic formulas for determining the thermal loads required depending on the outside air temperature, the hydraulic calibration calculation of the existing network from boiler house No. 1364 are described. Volgograd, determination of the internal hydraulic characteristics of the resistance of the heat network and determination of the required hydraulic regime for consumers of the microdistrict No. 1364, depending on the change in coolant flow due to the regulation of the speed of rotation of the pump impeller. As a result, the implementation of the transition from a qualitative to a quantitative method of regulating heat release is possible without serious hydraulic interventions.

Keywords: heat supply, control methods, heat carrier temperature, heat carrier consumption, boiler room, heat network, pump, frequency-controlled drive, hydraulic modes, thermal energy saving