New issues - Известия Казанского государственного архитектурно-строительного университета.

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Maintenance №:3 Year:2023


CONSTRUCTION MECHANICS
Mishurenko N.A., Semenov A.A.   Buckling of shallow shells of double curvature considering the presence of discretely introduced weakening Стр.6
Resume:

Problem statement. There are frequent cases of constructive weakenings as a part of shell structures. At the same time, considering the effect of weakenings on buckling significantly complicates the method of calculating these structures. The purpose of this work is to determine the effect of discretely introduced weakenings on the buckling of shallow shells of double curvature. The objectives of the study are to create a mathematical model that considers geometric nonlinearity, transverse shifts, orthotropy of the material, weakenings of the structure; choice of algorithm for studying the buckling of the shell; writing a program to implement the selected algorithm. Results. The paper presents a geometrically nonlinear mathematical model of deformation of orthotropic shallow shells of double curvature, weakened by notches. The model is based on the hypothesis of the Timoshenko-Reisner shell theory and is presented as a functional of the total potential strain energy. To find the minimum of the functional, the Ritz method is used, which reduces the problem to solving a system of nonlinear algebraic equations, the solution of which is carried out by the Newton method. The algorithm is implemented in the Maple 2022 software package. For the structures under consideration, it has been established that when up to 10 % of the structure volume is switched off from work, the decrease in the critical load does not exceed 25 %. Conclusions. The significance of the obtained results for structural mechanics lies in the fact that a mathematical model has been obtained that considers geometric nonlinearity, transverse shifts, material orthotropy, structural weakenings, the use of which will allow us to investigate the stress-strain state and buckling of shell structures with greater accuracy.

Keywords:
shells, weakenings, buckling, critical load, Ritz method, Newton method
FOUNDATIONS, UNDERGROUND STRUCTURES
Mirsayapov I.T., Sharaf H.M.   Settlement of foundations of clay soils under block cyclic loadingСтр.18
Resume:

Problem statement. In full-scale conditions of construction and exploitation, loads on soil bases are applied in stages as buildings and structures are constructed, with periods of active loading during construction passing into periods of endurance at different values of loads during exploitation. The purpose of the study is to develop a method for calculating the settlement of foundations on clay soils under block cyclic loading. The objectives of the study are: to analyze the existing methods of calculating the settlement of foundations on clayey soils under different mode cyclic loads and to conduct experimental and theoretical studies of foundation settlement under block cyclic loading on clayey soils. Results: we propose and implement an engineering calculation method of foundation settlement based on the application of the layer-by-layer summation method that takes into account the parallel change in the spatial stress-strain state and the mechanical properties of clay soils under the regime block cyclic loading. Conclusions: The significance of the obtained results for the construction industry consists in the fact that the proposed method for calculating foundation settlement makes it possible to assess more accurately the behavior of clay soils in the design of foundations of buildings and structures that are subjected to block cyclic loading.

Keywords:
clay soil, foundation settlement, block cyclic loading
BUILDING MATERIALS AND PRODUCTS
Khantimirov A.G., Sulejmanov A.M., Abdrakhmanova L.A., Nizamov R.K., Khokhryakov O.V.   The effect of modification on the durability of polyvinyl chloride wood-polymer compositesСтр.26
Resume:

Problem statement. One of the main problems in building materials science is the production of durable materials. For wood-polymer composites, this issue is particularly acute: the use of wood filler and operation in harsh climatic conditions negatively affect the properties. The positive effect of various modifiers on the physical and mechanical properties of wood-filled composites, such as carbon-based additives and fibrous fillers, is well known. However, such modified composites have not been sufficiently studied in terms of durability. The purpose of the work is to study the properties of wood-polymer composites based on polyvinyl chloride in conditions of artificial accelerated aging. The objectives of the study are: to study the influence of climatic factors on the strength properties and appearance of modified wood-polymer composites and to predict their service life. Results. The paper presents the results of accelerated tests for climatic effects of modified wood-polymer composites based on polyvinyl chloride. Carbon nanoadditives and fibrous fillers, which had previously shown their effectiveness for strengthening wood-filled composites, were used as modifiers. The most effective modifiers according to the test results are carbon additives (mechanically activated petroleum cokes and nanotubes), which showed a decrease in bending strength loss after accelerated aging by 1.9-4.1%. Conclusions. The significance of the results obtained for the construction industry is that forecasting the service life of wood-polymer composites based on polyvinyl chloride with increased strength properties will expand the scope of products based on them, including structural purposes.

Keywords:
polyvinyl chloride, wood-polymer composite, basalt fiber, asbestos, fiber modifier, climatic tests, accelerated aging tests
Gotlib E.M., Tverdov I.D., Galimov E.R., Dolgova A.V., Gimranova A.R.   Comparison of modifying action in epoxy compositions of diopside containing fillers based on technogenic and vegetable raw materials Стр.36
Resume:

Natural diopside has high electrophysical and strength characteristics, as well as resistance to acids, which causes its use in various types of ceramics. In addition, it is quite effective as a filler of polymer materials, which is shown by the example of polyester resins. However, due to the high cost of extraction and high labor costs for grinding solid rock, dispersed diopside-containing filler is practically absent on the domestic market. In this regard, the main problem is the uneven distribution of the diopside deposit across the territory of Russia. This makes it relevant to synthesize diopside-containing fillers based on available, inexpensive domestic raw materials, in particular, metallurgical slag and rice husk ash. The purpose of the work is to study the phase composition and properties of diopside - containing fillers based on man - made and vegetable raw materials and to study their modifying effect in epoxy compositions to improve the complex of performance indicators. The objectives of the study to achieve this goal are to study the basic properties of diopside-containing fillers, such as phase composition, porosity, surface pH, oil capacity; analysis of the physical and mechanical characteristics of epoxy compositions filled with these fillers. Results. The paper presents the results of studies of diopside-containing fillers obtained on the basis of ferrous metallurgy waste and rice cereal production. The filler based on metallurgical slag contains 4 times less amount of the target product – diopside than the one obtained on the basis of rice husk ash. The diopside-containing filler based on metallurgical slag has significantly lower porosity compared to the filler, which is synthesized on the basis of rice husk ash. The specific surface area of its pores is less by 30%. Modification of epoxy polymers with diopside-containing fillers provides a significant reduction in the coefficient of friction and an increase in the wear resistance of materials based on them, that is, their high tribological characteristics. At the same time, the hardness of the filled compositions and their adhesion to steel increases. Conclusions. The use of diopside-containing fillers is effective for the modification of epoxy polymers and the development of protective coatings of metal structures and adhesive compositions based on them.

Keywords:
diopside, fillers, epoxy materials, rice husk, metallurgical slag
Belyakov A.Yu., Khokhryakov O.V., Khozin V.G.  Functionalized mineral filler is an effective modifier for cement concrete Стр.45
Resume:

Mineral fillers and surfactants (plasticizers) make it possible to regulate the rheological properties of concrete mixtures, increase the physical and mechanical properties of concrete, and also reduce the consumption of cement in them. However, the most common method remains the introduction of chemical additives into the composition of concrete mixtures with mixing water, and the use of mineral fillers (pozzolanic, hydraulic, inert) in practice is less common. An alternative to the separate use of plasticizers (and other chemical additives) and fillers can be the forced “fixation” of the former on the surface of mineral particles when they are ground together. Functionalized fillers obtained in this way can be used as modifying additives in cement concrete, superior in efficiency to known organomineral additives. The article examines the effect of functionalization of mineral fillers of various chemical nature with superplasticizers on the mobility of cement-mineral suspensions and concrete mixtures, and on the physical and mechanical properties of heavy concrete. The purpose of the study is to obtain functionalized fillers that provide increased efficiency of superplasticizers in concrete mixtures. To achieve the goal, the following tasks were set: 1. To establish the maximum effective concentrations of superplasticizers in cement-water suspensions; 2. To determine the mobility of cement-mineral suspensions and justify the effectiveness of using functionalized fillers; 3. To investigate the particle size distribution in functionalized fillers; 4. To study the effect of functionalization of fillers on the water requirement of concrete mixtures and the strength of concrete. Results. A method for increasing the efficiency of superplasticizers in mineral-water suspensions by functionalizing mineral fillers has been substantiated. In heavy cement concrete, the method can significantly improve the technological and physical-mechanical properties. Conclusions. The significance of the results obtained for the construction industry is to increase the strength properties of concrete using functionalized fillers obtained from isoplastic concrete mixtures, which allows reducing the consumption of Portland cement without reducing the physical and mechanical properties of concrete.

Keywords:
functionalized filler, superplasticizer, plasticizing ability, cement concrete, concrete modifier
Kamalova Z.A., Valiev A.I.   Calculation of glue covering panels, the issues of their durabilityСтр.57
Resume:

One of the problems of wide application of glue plywood covering panels in the construction industry is the possibility of using typical panels for different climatic zones. The purpose of the study is to calculate the glue plywood panels, to study the issues of their durability. The main objectives of the study are the thermal calculation with subsequent selection of the insulation thickness of "warm" glue plywood panels for different climatic zones, strength calculation, evaluation of the effect of thermal aging on the physical and mechanical properties of the most stressed material of the panel (plywood), which affects the durability of the product. Results. A typical glue plywood covering panel was considered in the work, calculations were performed, conclusions were made about the possibility of its use for various climatic zones, the most stressed material in the panel was determined, changes in the physical properties and mechanical strength of plywood during the process of thermal aging were studied, and the durability of the original and aged plywood was assessed. Conclusions. The significance of the results obtained for the construction industry lies in determining the performance of typical glue plywood covering panels for various climatic zones, the possibility of further studying the durability of glue plywood covering panels, and expanding the scope of application of these types of products.

Keywords:
glue covering panel, durability, thermal aging, transverse bending, strength
Smirnov D.S., Belyaeva K.R., Khokhryakov O.V.   Investigation of the properties of fine-grained asphalt concrete designed by different methods Стр.66
Resume:

The road structural layers consist of the underlying layer, the base and the coating layers. It perceives pressures from mobile loads and distributes them along the roadbed. Since the greatest pressure occurs on the surface and decreases in depth, the road needs durable structural layers, which in turn require the use of high-quality materials compacted to a high density. The aim of the work is a comparative analysis of the stability of asphalt concrete, selected by different methods, to the formation of plasticity rutting. The objectives of the study are the selection of composition by methods of limit curves of dense mixtures, volumetric design methods, as well as evaluation of the physical and mechanical properties of asphalt concrete mixtures selected by various methods and evaluation of the propensity of selected compositions to form plasticity rutting. Results. The paper presents the results of comparative tests of asphalt concrete selected by volumetric design methods (SP-16, A16ВН) and the method of limit curves (type B Grade I), as well as the results of testing samples of asphalt concrete for the formation of plasticity rutting. Comparative tests of the physical and mechanical properties of asphalt concrete SP-16, A16ВН and type B Grade I showed that the coefficient of water resistance for asphalt concrete SP-16 and A16ВН meets the requirements of regulatory parameters and is (0.96%) for SP-16, (0.93%) for A16ВН. For asphalt concrete Type B grade I, the coefficient of water resistance is (0.79%). The results of tests for the formation of plasticity rutting showed that for asphalt concrete SP-16 and A16ВН, the rutting meets the requirements of regulatory documents and is 2.29 mm and 5.74 mm, respectively, and for asphalt concrete Type B grade I is 12.22 mm. The coefficient of water resistance and resistance to rutting of asphalt concrete Type B grade I is significantly inferior to asphalt concrete SP-16 and A16ВН. Conclusions. The results of the study will allow us to draw conclusions about the most effective methods of selecting asphalt concrete from the point of view of resistance to the formation of plasticity rutting. The data obtained can be used in the construction and operation of the road surface to increase its durability and stability.

Keywords:
road structural layers, asphalt concrete, grain composition, frost resistance, water resistance, rutting
Stroganov V.F., Strakhov D.E., Stroganov I.V., Akhmetshin A.S.   Study of hydrostatic pressure on the structure and properties of epoxy rubber polymers with the “shape memory” effectСтр.77
Resume:

One of the problems in producing epoxy compositions, especially in the presence of high-viscosity modifiers, is the compatibility of the components. Increasing the level of compatibility ensures a positive change in both technological and operational characteristics of the compositions and the polymer. The purpose of the work is to study the effect of physical modification (high hydrostatic pressure) on high-viscosity epoxy rubber oligomer compositions to increase the level of their homogeneity and physical and mechanical characteristics of epoxy polymers. The objectives of the study are: to determine changes in the structural and strength parameters of epoxy polymers as a result of physical modification. It has been established that a change in hydrostatic pressure affects both the change in structure: molecular weight of interstitial fragments (Mc) and effective density of polymer network nodes (Vc), glass transition temperature (Tс), and strength indicators: tensile strength (?p), modulus of elasticity (E) and relative highly elastic deformation (?в.э.). The significance of the results obtained for the construction industry lies in expanding the possibilities of changing manufactured industrial modifiers for the production of various composite materials, for example, shape memory couplings for connecting pipelines, including those made of dissimilar materials.

Keywords:
physical modification, hydrostatic pressure, structure and properties, intermolecular interactions, shape memory effect
Khokhryakov O.V., Gulyakov E.G., Khozin V.G., Belyakov A.Yu.   Problems of efflorescence in concrete vibro-pressed paving slabsСтр.86
Resume:

Currently, concrete products for sidewalk coverings are actively used in landscaping. They are distinguished by their expressiveness, ease of production and installation, different colors, as well as a wide range. Throughout the entire period of operation, the products are under the influence of many types of influences, which include precipitation, solar radiation, drying, alternating freezing and thawing, mechanical wear, de-icing reagents, etc. Most often, defects appear on the front surface in the form of efflorescence and efflorescence, although their presence does not affect the physical and mechanical properties, but reduces the aesthetic quality. The purpose of this study is to analyze modern data and conduct physical and chemical tests of concrete paving slabs to identify the causes of efflorescence and changes in their color. To achieve this goal, the following tasks were identified: 1. Perform an analysis of literature data on the causes of efflorescence on cement concrete products. 2. Determine the color change of concrete slabs; 3. Conduct comparative microscopic studies of the surface of concrete slabs; 4. Study the pH environment of the aqueous solution in which the concrete samples were located; 5. Conduct a qualitative assessment of efflorescence; 6. Determine the content of chlorine ions in concrete slabs. Results. As a result of the research, the main factors causing efflorescence and discoloration of paving slabs were identified. When comparing the appearance of reference products with samples taken from the site, an increased difference in the color of their surface was revealed between them. The main cause of efflorescence has been determined - leaching of hydrated lime, which is also supplemented by the migration of active substances to the surface when moisture acts on the products due to their increased porosity. Based on the results of the study, recommendations were developed for adjusting the production technology of paving slabs. Conclusions. The value of the results lies in identifying the factors leading to efflorescence and discoloration of concrete slabs, and in justifying ways to eliminate them.

Keywords:
concrete, efflorescence, fine-grained cement concrete, slabs for sidewalks, vibropressed slabs
BUILDING STRUCTURES, HOUSES
Antakov I.A., Suleymanov A.M.   Deformability of flexural concrete members reinforced with fiber-reinforced polymer barsСтр.101
Resume:

The behavior of flexural members with fiber-reinforced polymer reinforcement under load has a number of features fundamentally different from reinforced concrete, which is a consequence of differences in the physical and mechanical properties of composite and steel reinforcement. At the same time, the development of existing methods for calculating structures with fiber-reinforced polymer reinforcement was carried out by adapting existing methods for calculating reinforced concrete structures, by introducing and adjusting various empirical coefficients. In this regard, the purpose of this study is to improve the methodology for calculating the deflections of flexural concrete members reinforced with fiber-reinforced polymer reinforcement. The research objectives include the analysis of existing study in this area and existing methods for calculating flexural members and structures with fiber-reinforced polymer reinforcement, identification of their features and differences; experimental studies of the deformability of beams with fiber-reinforced polymer reinforcement, comparison of experimental data on deflections and theoretical data determined by the considered calculation methods; conducting theoretical studies aimed at developing recommendations for calculating the deflections of these structures. Results. The analysis of the conducted experimental studies of concrete beam specimens with the cross section of 120 ? 220 mm and the length of 1810 mm, reinforced in the tension side with two bars of glass fiber-reinforced polymer reinforcement was carried out. The tests were carried out with a short-term application of loads. A comparison was made of the theoretical dependencies, determined according to the guidelines of Russia – Set of Rules 295.1325800.2017 and the United States of America – American Concrete Institute 440.1R-06, and experimental dependencies between the values of the bending moment and deflections. It was found out that with increasing load, the reliability of the calculation of deflections by the methods under consideration decreases. It was proposed to calculate the deflections of flexural members with fiber-reinforced polymer reinforcement according to the method of Set of Rules 295.1325800.2017, taking into account the developed correction factor k. Conclusions. The use of the developed coefficient k made it possible to improve the accuracy of assessing the deformability of flexural members with fiber-reinforced polymer reinforcement.

Keywords:
glass fiber-reinforced polymer reinforcement, fiber-reinforced polymer reinforcement, non-metallic reinforcement, flexural members, concrete structures, deflection
Zinnurov T.A., Novitsky E.V., Permyakov S.V., Sulejmanov A.M.   Analysis of the operation of cylindrical polymer composite dowels in wooden composite bending elements Стр.110
Resume:

In the modern world the issue of affordable construction of buildings and structures in remote settlements, especially in the northern regions, is acute. The solution to this problem can be the widespread introduction of prefabricated structures, for example, from wood. The design of a composite wooden beam with polymer composite dowels considered in this article potentially has a number of advantages compared to traditional wood solutions, as well as compared to materials such as steel, reinforced concrete. The purpose of the work is to analyze the shear behavior of pins in a wooden bending structure. The objectives of the study are to create a wooden two-tier composite beam from beams combined with polymer composite dowels and to conduct a series of sample tests, determine the values of vertical deformations of the composite beam and the mutual displacement of the ends of the beams with a different number of dowels, in addition, to compare the experimental data obtained with analytical calculations. Results: Based on the experimental model of a composite wooden beam, successful integration of a dowel system into the overall performance of the composite structure was demonstrated. Analytical dependencies were derived to examine the influence of the number of dowels on the overall flexure of the investigated wooden composite element. Conclusions: For the considered wooden composite beam, a linear relationship between vertical deformations and the number of dowels can be affirmed under loads not exceeding 50% of the load-bearing capacity. Polymer composite dowels are not uniformly engaged in shear, as evidenced by the obtained deformations and failure modes of the wooden composite beams. It can be noted that the most effective number of dowels is six, positioned at the edges of the bending element.

Keywords:
wooden composite beam, reinforcement, load-bearing capacity, dowel connection, flexure, polymer composite reinforcement, shear
Mirsayapov Ilshat T., Minzyanov R.I., Zainutdinov A.M.   Numerical study of the stress-strain state in the contact zone of concrete and reinforcement under static loading Стр.122
Resume:

The Finite Element Method is used to simulate the behavior of the concrete-reinforcement contact zone when testing the pull-out of a single bar embedded in a concrete block. In the proposed model, elements are introduced into the contact zone, simulating deformations of reinforcement and surrounding concrete and simulating load transfer. This approach allows accurate modeling of the nonlinear response at high confining pressures. The purpose of the study: for given geometric, physical and mechanical characteristics, to choose the most appropriate theories of the strength of materials for using the created model in solving scientific, technical and engineering problems. To achieve this goal, it is necessary to perform a number of tasks: create a computer model, set the necessary characteristics of materials for it to work correctly; perform a verification calculation, compare it with existing experimental and theoretical studies; make a conclusion about the performance of the model and the areas of its application. Results. We propose a model in the Ansys software package based on the finite element method. When developing the model, the experience of domestic and foreign scientists and researchers in terms of the choice of finite elements was taken into account. The model takes into account the real geometric, mechanical, physical parameters of objects. The model allows you to set different geometry and physical and mechanical characteristics of materials. The test results of 9 samples were obtained. A comparison of the finite element model with full-scale experiments is given. Conclusions. As a result of the comparison, it was established that the calculation by the proposed numerical model is in good agreement with the results of experimental studies by other authors. This model is recommended to be used to determine stresses and displacements in the contact zone "concrete-reinforcement" for solving scientific and engineering problems.

Keywords:
reinforced concrete; adhesion of reinforcement to concrete; finite element method; concrete damage plasticity model 2 (CDPM2); pull-out test
Mironova J.V., Suleymanov A.M.   Constructive solution of the joint of columns with the floor slab in a prefabricated-monolithic frame to increase resistance to progressive collapse Стр.135
Resume:

The main problem of ensuring the resistance of precast concrete to progressive collapse is the need to modernize standard structural solutions of joints, as the most vulnerable elements of frame and frameless buildings. The regulatory documents provide recommendations mainly for monolithic frames of buildings and structures, the issue for precast reinforced concrete has not been studied enough. The purpose of the work is to determine the features of the stress-strain state of the prefabricated monolithic frame and the modernization of the structural solution of the joint of the column with the overlap based on the results of numerical modeling. The objectives of the study are: to identify the most dangerous scheme of progressive collapse of the frame of a multi-storey building, to determine the features of the work of a prefabricated monolithic joint of a column with a critical destruction scheme, to develop and numerically simulate a constructive solution of the joint. Results. The paper presents the results of numerical studies of a prefabricated monolithic frame with progressive collapse, the results of modeling and the adopted design solution of the joint, which increases the resistance of the frame to avalanche-like destruction. Conclusions. The significance of the results obtained for prefabricated monolithic construction consists in obtaining new data on the performance of the frame elements and developing recommendations for the modernization of the joint.

Keywords:
multi-storied buildings, prefabricated-monolithic reinforced concrete frame, progressive collapse, joint of a column with a floor slab, stress-strain state
Mirsayapov Ilshat T., Lim V.A., Mirsayapov A.I. , Suleymanov A.M.   Evaluation of the effectiveness of the use of high-modulus polymer composite reinforcement Стр.145
Resume:

The interest of the enterprises of the construction industry in products made of polymer composite materials is growing every year. Along with the well-known advantages of polymer composite reinforcement, there are disadvantages that prevent its use in large-scale construction. The most characteristic disadvantage is the low modulus of elasticity compared to steel. This imperfection can be eliminated by using high-modulus polymer composite reinforcement in the structures. The purpose of the work is to evaluate the effectiveness of the use of high-modulus polymer composite reinforcement in bending elements. The objectives of the study are to assess the strength in normal sections of bent concrete beams reinforced with high-modulus polymer composite reinforcement, as well as to compare the bearing capacity of concrete beams reinforced with steel, low-modulus and high-modulus polymer composite reinforcement. Results. The paper proposes a comparative assessment of the increase in the ability of bending concrete beams in normal sections, reinforced with high-modulus polymer composite reinforcement, steel reinforcement and low-modulus polymer composite reinforcement. Conclusions. The significance of results obtained for the construction industry lies in the fact that the use of high-modulus polymer reinforcement increases the load-bearing capacity of concrete bending elements, while having a significant high elasticity compared to steel.

Keywords:
non-metallic reinforcement, high-modulus polymer composite reinforcement, strength of normal cross-sections, concrete structures, bendable elements
DESIGN AND CONSTRUCTION OF ROADS, SUBWAYS, AERODROMES, BRIDGES AND TRANSPORT TUNNELS
Vdovin E.A., Bulanov P.E.,. Khusaenov B.K, Vybornov D.R.   Modification of road soil-cement with nanosilica Стр.154
Resume:

The relevance of the study is justified by the need to increase the level of construction and technical characteristics and durability of soil-cement in pavement layers, as well as to reduce the content of mineral binder in reinforced soils, using nanosilica as an effective modifier. The aim of the work is to study the physical and mechanical characteristics of soil-cement modified with nanosilica. Results. The effect of modification of soil-cement with nanosilica on the levels of indicators of compressive strength, tensile strength in bending and freeze-thaw durability has been established. The optimal content and efficiency of nanosilica for soil-cement, which ensure their possible use in the structural layers of pavements, has been determined. Conclusions: It has been established that the modification with nanosilica ensures that the soil-cement achieve the M40 strength grade with a content of 8 % Portland cement and 0.6 % modifier or 10 % Portland cement and 0.45 % modifier by weight of the soil. Based on the regulatory requirements, the developed modified soil-cement can be used for the construction of structural layers of bases and coatings of transitional and lightweight types of pavement, depending on road and climatic conditions. However, insufficient values of frost resistance coefficients limit the applicable scope of the obtained cement soils in pavements. For further increase of the levels of physical and mechanical characteristics, additional studies on the processes of modifying soil-cement with nanoparticles are needed.

Keywords:
soil-cement, nanosilica, clay, strength, freeze-thaw durability, vortex apparatus
Komarova T.K.   Mathematical modelling of the automobiles and pedestrian moving on the unsignalized junction Стр.163
Resume:

One of the most common elements of the urban road network is an unsignalized junction at the same level equipped with a pedestrian crossing. The purpose of the study is to determinate the capacity of traffic lanes at an unsignalized junction at the same level with pedestrian traffic. The objectives of the study are to develop a mathematical model of the movement of traffic and pedestrian flows at an unsignalized junction at the same level, to propose a hierarchy and a design scheme for the movement of cars and pedestrians, to determine the capacity of the lanes of a minor road, to substantiate the reliability of the results of mathematical modelling. The mathematical model represents a complex system of equations that need to be applied depending on the proposed hierarchy of traffic flows, taking into account pedestrian traffic. The article presents the stages of development and the results of mathematical modelling of the movement of cars and pedestrians on unsignalized junctions in order to determine their capacity. The comparison of the results of field studies and mathematical modelling of the capacity of the right-turn lane of a minor road is carried out. The proposed model and the simulation results can be used to determine the capacity during the design, reconstruction and overhaul of unsignalized junctions at the same level with pedestrian traffic.

Keywords:
capacity, unsignalized junction, pedestrian crossing, mathematical model, traffic, headway
TECHNOLOGY AND ORGANIZATION OF CONSTRUCTION
Khuziakhmetov R.A., Khuziakhmetova K.R., Rasulev F.R.   Prevention of collapse of pit and trench walls in cramped conditions of built-up areas Стр.175
Resume:

The experience of construction of new buildings and repair and restoration works in the conditions of dense urban development allows ensuring the safety of work performance of the underground part of buildings on the historically established territories. The purpose of this research is to study design and technological solutions to prevent the collapse of the walls of pits and trenches for foundations of various depths in cramped urban conditions. The following tasks were solved to achieve this goal: 1. The information and analytical review of design solutions for construction, repair and reconstruction projects in cramped urban conditions was carried out. 2. The review of modern experience in the organization and technology of zero-cycle work during the construction and renovation of buildings in cramped urban conditions was carried out. 3. The review of design solutions and regulatory requirements to ensure the stability of the walls of trenches and pits was completed. Results. The performed review of new construction sites with a simultaneous reconstruction of existing buildings of urban development allows stating that a full survey, as well as the qualitative design and construction of underground and above-ground parts of buildings is a guarantee of safe implementation of construction and erection works. Conclusions. The safety of the object of construction and repair in the cramped conditions of dense urban building is linked to the preservation of serviceable condition of all existing buildings on the territory under development, as well as the avoidance of dangerous situations at each stage of construction of new facilities. At the same time, it is necessary to take into account the limited possibility of deployment of the necessary size of the construction site in comparison with the unconstrained conditions determined by the regulatory requirements for new construction. The analyzed structural solutions of trench and excavation wall supports ensure compliance with the safety requirements at the construction site. At the same time, during the development and backfilling of shallow excavations, it is required to observe the requirements of safe work performance. The individual schemes of structures for strengthening vertical walls of trenches and pits considered by the authors in various combinations make it possible to perform new combinatorial schemes of fastening, the execution of which is focused on the use of traditional and modern lightweight building materials and products.

Keywords:
safety of construction works, cramped conditions, stability, soil collapse, fixing the walls of trenches and pits
ARCHITECTURE THEORY AND HISTORY. HISTORICAL AND ARCHITECTURAL HERITAGE RESTORATION AND RECONSTRUCTION
Kotkova A.V., Aidarova G.N., Suleymanov A.M.   Architectural formation of recreational and health-improving environment in the conditions of the Republic of TatarstanСтр.185
Resume:

Trends in the development of physical activity are being dynamically introduced into public life. The purpose of the study is the architectural formation of the recreational and health-improving environment in the conditions of the Republic of Tatarstan. The main tasks include identification of the conceptual and terminological framework; determination of the factors influencing the formation of the recreational and health-improving environment, development of a functional and architectural-typological model of the recreational environment in the suburban area of Kazan. Results. The basic concepts and terms related to the recreational and health-improving environment are identified including: "health routes", "health tourism", "ecological trails". Three types of recreational and health-improving environments are distinguished: open, closed and complex. Four health routes in the suburban area of Kazan and typological table of objects of architectural and spatial formation of recreational and health-improving environment of open type were developed. Conclusions. The formulated principles and the revealed typology of objects of architectural and spatial formation of recreational and health-improving environment allowed creating an experimental model of health promotion routes in the suburban area of Kazan. Rich natural landscapes can be used for the architectural formation of year-round health routes in the conditions of Tatarstan.

Keywords:
architectural and typological principles, recreational and health-improving environment, health routes, ecological path, functional architectural and planning model
Sementsov S.V., Slavina T.A.   On the typology of the formation of the metropolitan urban planning environment of St. Petersburg - Petrograd – LeningradСтр.200
Resume:

Keywords:
St. Petersburg, morphology of the urban planning framework, building blocks and plots, different types of urban planning environment
Suleymanov A.M., Khabibulina A.G., Petrov A.S.   The problem of erosion of facades of historic buildings from wind impact of rain Стр.214
Resume:

The relevance of the study is due to the fact that surface erosion of building materials is a common phenomenon observed on the facades of historic buildings. Climatic changes may lead to an increase in the frequency and intensity of extreme precipitation events, which may increase erosion effects on building facades due to the impact of oblique rainfall. The aim of the study is to compare experimental methods for assessing the degree of surface erosion of historic building materials under the influence of oblique rainfall. The objectives of the study are to review modern methods of measuring the effect of rain with wind on surface erosion and strength reduction of bricks and limestone; to analyze the most known methods of assessing the degree of erosion of the surface of building materials; to propose recommendations for the protection and restoration of damaged facades of cultural heritage objects due to the impact of oblique rain. Results. Based on the analysis of modern research, recommendations for the protection and restoration of damaged facades of cultural heritage objects due to the effects of oblique rain are proposed. Kazan State University of Architecture and Engineering has created a testing complex «Sealed chamber», which allows conducting further experimental research to assess the impact of oblique rain on surface erosion and strength reduction of building materials taking into account the advanced foreign experience. Conclusions. The significance of the results obtained for architects and designers is that the use of the methods for assessing the degree of damage to the facades of architectural monuments due to the effects of oblique rainfall allow monitoring and developing measures to protect cultural heritage sites.

Keywords:
wind-driven rain, erosion of masonry, protection of facades of monuments
Kuleeva L.M., Suleymanov A.M., Burova T.Yu., Listovskaya L.V.   Attic. History and modernityСтр.225
Resume:

The relevance of the topic considered in this article is determined not so much by its novelty - the attic, as a space-planning architectural element, has been known since the XVI century, but by the specifics of the modern consideration of a complex of professional issues related to the design of attics. The purpose of the study is the systematization of transformations of structural, functional, planning and architectural solutions for the volume of attics in the conditions of modern construction. The objectives of the study are highlighting the main stages of the history of the development of the attic in architectural practice; identification of issues that determine the formation of the attic as an architectural volume; determination of the impact of new materials and technologies on the design and functional planning solutions of attics. Outcomes. The study showed that the attic in the process of its development, having undergone objective changes in constructive and functional-planning solutions, remains a relevant topic of architectural and design practice, revealing itself in new versions, using the capabilities of the latest materials, technologies and design justifications. Findings. The results obtained contribute to the formation of an algorithm for solving problems in the conditions of modern design of attics, including issues not only of finding and justifying new architectural proposals and considering the elements of the superstructure of attic floors, but also issues of reconstruction measures related to the restoration of historical heritage.

Keywords:
attic, design features, varieties of functional use, features of the planning organization of attics, functional and technological elements of attics
Shaimardanova C. A., Prokofiev E. I., Suleimanov A. M.   Integration of transport hubs into the urban environmentСтр.234
Resume:

The provisions of the conception of transit-oriented development of territories make it possible to organize urban development that is comfortable for the population. The purpose of the study is to determine the principles for the formation of transit-oriented territories in residential development with a focus on public transport. To achieve this goal, the following objectives were identified: 1. the study of international experience in the design and implementation of projects for the formation of residential development with respect to transit-oriented territories; 2. determination of the characteristic features of the formation of transit-oriented territories, with a focus on public transport. Results. As a result of the study, the experience of design, development and housing development of land under the conditions of transit-oriented approach was reviewed using the example of cities in Malaysia, France, Denmark, and Great Britain. Principles for the formation of transit-oriented territories were identified, such as: concentration of high-intensity development, fullness of public functions; combination of residential, work, shopping and entertainment facilities; formation of urban pedestrian spaces based on alleys; adaptation of the urban environment to bicycle infrastructure; environmental friendliness based upon financial incentives. Conclusions. The significance of the results obtained for urban planners and architects lies in the opportunity to take into account in their work the principles of the formation of transit-oriented territories, which will provide easy access to public transport and create conditions that make the area attractive for transit passengers.

Keywords:
transit-oriented territory; urban development; residential development; urban transport network; public transport
ARCHITECTURE OF BUILDINGS AND STRUCTURES. CREATIVE CONCEPTS OF ARCHITECTURAL ACTIVITY
Nureyev T.M.   Architecture design methodology for honeycomb articulated residential development Стр.243
Resume:

The relevance of the study lies in the absence of a methodology for designing the architecture of a new type of development - a honeycomb articulated residential development (HARD), which is also absent in the implementation. The purpose of the study is to create a methodology for designing the architecture for a honeycomb articulated residential development in the central and southern insolation zones of Russia. Research objectives: 1) Creation of conditions for increasing the economic efficiency of urban planning solutions. 2) Creation of a minimum number of multi-beam residential sections, the connection of which will lead to the formation of a honeycomb articulated residential development. 3) Creation of conditions for the energy efficiency of apartments in the framework of stimulating the growth of the family factor in Russia. Results. The study presents the following results: 1). A methodology for an effective three-stage design of a honeycomb articulated residential development has been created. 2). A multiplier effect has been created in the form of three directions for further research in the construction physics of residential development: A). A method for calculating the energy efficiency of apartments in the azimuthal sectors of a symmetrical half of the yard of a mesh closed polygonal residential development has been created. B). Methods for controlling the microclimate of the yard of a honeycomb articulated residential building are proposed. Conclusions. The significance of the results lies in the creation of a methodology for designing the architecture of a honeycomb articulated residential development for the central and southern insolation zones of Russia from two residential sections: the parent "T" - shaped and the child "Y" - shaped. The obligatory introduction of a stylobate volume for honeycomb articulated residential development makes it possible to create comfortable living and working conditions not only in the settlements of the center of the country, but also in the extreme conditions of the North of Russia, ensuring the maximum population density rate.

Keywords:
full square kinetics, multi-beam architecture, honeycomb articulated residential development, parent and child residential sections
Shumilov K.A., Guryeva Yu.A.   Modeling of rod and polygonal structures of complex geometry using the Grasshopper program Стр.257
Resume:

Konstantin A. Shumilov, candidate of technical sciences, associate professor, Saint Petersburg State University of Architecture and Civil Engineering, Saint Petersburg, Russian Federation E-mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it Yuliana A. Guryeva, candidate of technical sciences, Saint Petersburg State University of Architecture and Civil Engineering, Saint Petersburg, Russian Federation E-mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it

Keywords:
architectural design, modeling, rod structures, polygonal structures, complex geometry, parametric programming, visual programming, Grasshopper, Rhino, Archicad, Revit
 
Russian (CIS)English (United Kingdom)

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