Problem statement. The large deflections of the rods loaded with compressive force and having a nonlinear elastic resistance to the rotation of their axis in the hinge supports are investigated. The aim of the work is to develop a methodology for calculating the compliance of compressed rods taking into account their post-buckling behavior with nonlinear elastic resistance to rotation on the support. Results. The resulting nonlinear integro-differential equation is obtained, the method for its solution is given. Conclusions. Linear relationships were found between the compliance of the rod to the action of the longitudinal compressive force on the relative displacement of the end of the rod and the angle of inclination of the axis of the rod on the supports from the compression force. The snap-through buckling effect is revealed in some geometric and mechanical characteristics of the rod and support. Using the proposed methodology, it is possible to perform the calculation of statically indeterminate structures, taking into account the buckling of rod elements with nonlinear elastic end restraints, and to identify the reserve of their bearing capacity.

Problem statement. The purpose of the study is to identify the regularities of the development of deformations of concrete in the compressed zone during cyclic loading of stationary and non-stationary modes. Since reinforced concrete structures of buildings and structures are exposed to cyclic loads of various modes and types of impact during operation, a fairly large number of methods for calculating the fatigue strength of reinforced concrete structures have been developed. However, these methods do not have sufficient experimental justification. Results. The main results of the study consist in experimental studies of the endurance of the normal sections of reinforced concrete beams of rectangular cross-section under stationary and non-stationary modes of cyclic loading. The nature of the development of damage and destruction of beams of the compressed zone concrete is established. Conclusions. The significance of the obtained results for the construction industry consists in establishing the regularity of the development of deformations of concrete in the compressed zone during cyclic loading of stationary and non-stationary modes. For the accepted parameters of loading of reinforced concrete beams, the destruction occurred along the concrete in a compressed zone due to the formation and development of fatigue cracks in the concrete. In the concrete of the compressed zone, under the cyclic loads, deformations developed, which increased regardless of the cyclic loading mode. The main part of the deformations occurred at the beginning of loading up to about 5?104-105 loading cycles.

Problem statement. In reinforced concrete bendable structures, under cyclic loads in the compressed zone of concrete, inelastic deformations of vibration creep are manifested and develop under connected conditions. This leads to non-stationary modes of deformation of concrete and reinforcement. Endurance calculation is a complex and difficult process. Therefore, it is necessary to develop a simplified methodology based on the well-known limit state method. Results. Experimental and theoretical studies of the endurance of reinforced concrete structures, under stationary and non-stationary modes of repeatedly repeated cyclic loading, have been carried out and a simplified method for calculating endurance by limiting forces has been developed. Conclusions. A new method has been developed for calculating the endurance of reinforced concrete structures by limiting forces under cyclic loads regime. In this simplified substitution, the change in the stress-strain state of the concrete of the compressed zone and the longitudinal stretched reinforcement is considered, taking into account the redistribution of forces between them in the process of cyclic loading.

Problem statement. The aim of the research is to study the effect of road construction waste (asphalt granulates, stone crushing screenings and thermoactivated dust of asphalt mixing plants) on the physical and technical properties of cement-sand-gravel mixtures for road pavements of highways. The relevance of the study is justified by the need to utilize waste generated during the milling of asphalt concrete pavements during the repair and reconstruction of highways, during the production of crushed stone in quarries, as well as the preparation of asphalt concrete mixtures at production bases. Results. The results of the study consist in determining the level of indicators of physical and technical properties (ultimate compressive strength, ultimate tensile strength in bending, frost resistance) of cement-sand-gravel mixtures with the addition of asphalt granulate, screening of stone crushing and thermoactivated dust of asphalt mixing plants. Modification of cement-sand-gravel mixtures with waste from road construction industries revealed the possibility of reducing the content of Portland cement in mixtures from 17 to 25%, depending on the grade obtained in terms of strength and frost resistance of the processed material of road pavements, and also expanded the methods of utilizing industrial waste and reducing their ecological impact on the environment. Conclusions. The dependences of changes in the levels of indicators of the main physical and technical properties of cement-sand-gravel mixtures modified by waste from road construction industries were revealed, on the basis of which the optimal compositions of materials for road pavements of highways were developed. It has been established that the introduction of thermally activated dust from asphalt mixing plants enhances the physical and technical properties and reduces the content of binder in cement-sand-gravel materials of road pavements, and utilization of asphalt granulate and stone crushing screenings is possible by adding them to materials as granulometric modifiers.

Problem statement. The aim of the study is to determine the effect of carbon nanotubes of various structures on the phase composition of a cement stone by IR spectroscopy obtained by a traditional method and by activating in a vortex layer apparatus. Results. According to the analysis of the obtained spectrograms, it was revealed that the modification of cement stone with carbon nanotubes obtained from Portland cement, activated in the vortex layer apparatus, leads to an increase in the amount of the silicate phase of Portland cement (by 12-39 %), which is confirmed by a decrease in the amount of Portlandite in these compositions by 8% compared with the control composition. In addition, modification with carbon nanotubes leads to a decrease in the content of the group of calcium hydrosulfoaluminates by 21-23 % in the compositions of the cement stone obtained without activation. The activation of Portland cement in the vortex layer apparatus together with carbon nanotubes does not contribute to a decrease in the amount of calcium hydrosulfoaluminates, in comparison with the unmodified composition obtained by activation. Conclusions. The significance of the results obtained for the construction industry is that for the first time it was proposed to disperse carbon nanotubes in the original Portland cement by means of their joint activation in a vortex layer apparatus. This method makes it possible to increase the content of the silicate phase in comparison with the traditional introduction of carbon nanotubes, as well as the physical and mechanical properties of the modified cement stone.

Problem statement. Gas supply to cities from main gas pipelines requires reducing the pressure of main gas to the value suitable for further supply to industrial and residential facilities of consumers through the gas distribution network. In existing simple schemes, the excess energy of the main gas pressure is spent on overcoming the resistance of the throttle valves, which makes it possible to obtain a reduced gas pressure of the required values. Currently, gas distribution stations for gas supply to industrial and residential facilities start using more complex schemes, in which the pressure of the main gas is reduced from 5.4 MPa at the inlet to 0.6 MPa at the outlet due to the use of turboexpanders on the reduction lines at design gas flow rates up to 180 thousand m3 / h. The average gas consumption values are still from 20 to 40 thousand m3 / h. The main natural gas enters the turboexpander through a high-pressure gas pipeline and then, due to expansion, the gas pressure is converted into mechanical energy of the rotor rotation, which is transferred to the connected electric generator to generate electricity. Turbine expanders with one-sided semi-open radial-axial impellers of various diameters are used, with an increase of which from 150 mm to 550 mm when the pressure is reduced from 5.4 MPa at the inlet to 0.6 MPa at the outlet, the efficiency decreases from 84% to 69% for constant gas consumption equal to 20 thousand m3/h. With a single-stage turboexpander, power generation with a gas consumption of 20 thousand m3 / h and a wheel diameter of 350 mm is 0.6 MW. With an increase in gas consumption, the efficiency increases, which for a flow rate of 40 thousand m3 / h with a wheel diameter of 350 mm is 0.82. The amount of electricity generated increases due to the increase not only in consumption, but also in the increase in the efficiency. Results. The article based on the study proposes a technology for the use of secondary thermal energy resources in the form of waste water for the purpose of increasing the temperature of the main gas sent to the turboexpander to expand and thereby increase the generation of electricity. On the basis of the study, a scheme has been developed in which a turboexpander consists of two rotary stages. One of which is used in a vapor compression heat pump cycle to drive a compressor during waste water heat recovery, and the other rotary stage is used directly to drive an electric generator shaft into rotary motion and generate electricity by external consumers. Since the movement of the main gas between the stages is sequential, in order to increase the generation of electricity, heating of the main gas is applied before each stage. Conclusions. The article solves the problem of energy saving and reducing the cost of natural gas by developing a technology and a scheme for increasing electricity generation when expanding the main gas in a two-stage turboexpander by using a low-potential energy resource in the form of heat waste water from a water treatment system using steam-compression heat pump units, with the help of which the heat of waste water the main gas is supplied before each stage, and the compressors are driven by mechanical energy obtained from the expansion of the main gas at each stage of the turboexpander.

Problem statement. Awareness of the importance of all the components of the regional architectural school, their special event-related forms of functioning is the key to the success of the school’s existence and development. The objective of the present work is to substantiate the use of the «architecture – theatre» analogy when considering the current architectural problems of the Kazan architectural school using Children’s Architectural and Design School «DASHKA» (Kazan State University of Architecture and Engineering, KSUAE) as an example. Results. The analogy «architecture – theatre» allows us to consider the usage of theatrical performance and various kinds of games and gamification in the educational process as a kind of an attribute of quality and comprehensiveness of any spatial and environmental education. The meaningful school environment is determined by the methods and techniques of spatial organization, as well as traditions that express themselves in the course of repeated collective actions. The information above shows the universal effect of project and game activities on creating conditions for the formation of a complex of professional identity properties. Conclusions. The significance of the achieved results for architecture lies in the definition and theoretical substantiation of one of the «DASHKA» school core traditions which is conducting themed theatrical performances. Establishing the «architecture – theatre» analogy proves the productivity of themed games and events activities in the implementation of the concept of environmental existence school.

Problem statement. The problem of the study is the lack of knowledge of the organization of architectural space for labor training, technical creativity of young people and the lack of the appropriate types of buildings development. The purpose of the study: to analyze the existing experience of organizing architectural space for labor training of young people, to identify the prerequisites and key typological features. Results. Identification of the prerequisites, factors of formation and classification features of the architectural organization of labor processes. The analysis revealed four main periods of development of labor processes from the architecturally unorganized conditions of labor training, to the formation of primary, secondary, and better equipped technical educational institutions with the separation of the functions of study, work, and technical creativity. Three classification groups in the spatial organization of modern labor processes are identified: 1) specialized stationary closed type; 2) specialized temporary closed-open type; 3) specialized open type. Conclusions. The significance of the obtained results lies in the theoretical understanding of the Russian and foreign experience in the formation of architectural space for labor training processes organization. The identified historical background and modern experience of the architectural organization of youth labor processes can be a theoretical basis for the design development of new types of buildings. The solution to the problem of organizing architectural space for educational and labor processes and technical creativity of young people can be multifunctional youth centers. The author’s experimental design model of the center for technical creativity of working youth is presented.

Problem statement. The research objective lies in the site analysis of the modern architecture of rural housing in Tatarstan; identification of the manor houses types, the features of their architectural appearance in comparison with the historical analogs of the rural houses of the Kazan Tatars. Results. The study identified the types of rural residential buildings, the general manor elements, traditional and new methods of decorative design. According to classification carried out, manor-type residential buildings make up six major groups. Among them: houses of the traditional type (wooden), ones made from silicate brick and red brick are among them; the manor buildings include garages, verandas, utility blocks. An increase in parameters, new finishing materials (siding), traditional decor techniques modernization and new decor techniques are the new features of the rural dwellings. Conclusions. The significance of the results obtained for science and practice lies in the theoretical understanding of the development of modern architecture in Russian villages, the degree of preservation of their traditions for the subsequent development of practical design recommendations. Single samples of residential buildings, barns, bath-houses, mills, sheds, stories from the past decades of the twentieth century have been preserved in the villages. Only a few examples of historic dwelling types as the architectural heritage have remained. The decoration of wooden and brick houses preserves, in a varying degree, the traditions of rural and urban Tatar houses of the second half of the 19th and early 20th centuries.