254 Works

Thermal-insulation boards from fibrous plant wastes and urea-formaldehyde binder

Tatiana Vahnina, Irina Susoeva & Andrey Titunin
Irreversible waste spinning flax and cotton are sent to landfill or incinerated, it adversely affects the environment, although it is desirable to use plant waste for production, which would be a very positive approach in terms of natural environment. Composite boards of irrecoverable waste from the processing of flax and cotton and urea-formaldehyde binder (UF) can be used as a thermal-insulation material, the development of this composite material is the purpose of this research. The...

Self-compacting concrete using pretreatmented rice husk ash

Roman Fediuk, Valeriy Lesovik, Alexandr Svintsov, Aleksandr Mochalov, Sergey Kulichkov, Natalia Stoyushko, Natalia Gladkova & Roman Timokhin
Self-compacting concrete was obtained by partially replacing Portland cement with a previously prepared rice husk ash Preliminary preparation included the thermal treatment of the ash under various conditions. The optimum technology of preparation, allowing to receive a homogeneous concrete mix is revealed. All concrete mixtures were designed in such a way as to have a slump flow of 680 ± 30 mm in diameter, which was achieved by using different dosages of a superplasticizer based...

Composition and rheological characteristics of bitumen in short-term and long-term aging

Bagdat Teltayev, Cesare Rossi & Saltanat Ashimova
This paper investigates the impact of sequential short-term and long-term aging of blown bitumen of the grade BND 70/100 on its mechanical characteristics in the temperature interval from 76°С to -36 °С. Group chemical composition of the bitumen has been determined by the method of liquid adsorption chromatography by the chromatograph “Gradient M”. Short-term aging has been performed in the vertical rolling thin film oven (RTFOT) under the standard of AASHTO T 240-08, and the...

Luminance distributions in the tropical sky conditions

Nguyen Phuong
Lighting engineering in construction is a complex scientific field, which requires the amalgamation of knowledge in the field of daylighting, construction and architecture, as well as other areas, including the humanities. Many studies have proven the benefits of natural light on health, activity, visual well-being and human productivity. Global environmental issues and the sustainable development movement require architectural design to achieve maximum energy efficiency. For all intents, daylighting calculations depend on the luminance distributions of...

Impact of forest fires on buildings and structures

Kristina Fryanova & Valeriy Perminov
The mathematical modeling of forest fires actions on buildings and structures has been carried out to study the effects of fire intensity and wind speed on possibility of ignition of buildings. The crown forest fire is introduced as a heat and mass source defined by the empirical values of average crown fire temperature and vertical gas velocity at the top crown surface dependent on fire intensity. The hydrodynamic and thermal interactions between plume, wind flow...

Инженерная кинематическая теория в приложении к расчету свайных фундаментов

Владимир Сергеевич Коровкин
Автор предложил вариант расчета свайного фундамента с применением инженерной кинематической теории контактного давления грунта. Приведено решение по определению сил трения на боковую поверхность сваи дополнительно зависящее от размеров поперечного сечения внедряемой в грунт сваи. Описано решение по определению реактивного давление грунта на острие сваи или условный фундамент для всего цикла нагрузки. Рассмотрено влияние расположения плиты ростверка в свайном основании на несущую способность конструкции. Учтено взаимное влияние свай на распределение усилий в свайном ростверке. Получено решение...

Composition calculation and cracking estimation of concrete at early ages

Tang Lam, Chuc Nguyen, Boris Bulgakov & Pham Anh
Recently, variety of large-scale constructions from monolithic concrete structures have been built in different regions of Vietnam. The application fields of these structures are extensive including the marine construction, underground structures, the high-rise building erection and others. However, structures damage and cracking, caused by temperature stresses, become more popular and strong impact on operation reliability and durability. In this study, the American standard ACI 211.1-09 was used to determine the composition of heavyweight concrete for...

Thermal cracking resistance in massive steel-reinforced concrete structures

Aleksandra Bushmanova, Daria Kharchenko, Kirill Semenov, Yuriy Barabanshchikov, Victoria Korovina & Aleksandra Dernakova
The work is dedicated to research of the thermal crack resistance in massive steel-reinforced concrete structures in construction period. The article examines the results of the analysis of the thermal stress state, which occurs in massive steel-reinforced concrete column. The steel part of the column is represented by a system of cross UC-beams. The study was conducted with using analytical models, which include the factor of steel profiles availability in comparison with simplified methods. Authors...

Method of calculating the optimal sand content in normal-weight concrete

Leonid Dvorkin
In the practice of proportioning concrete compositions, the optimum sand content in a mixture of aggregates is usually found empirically. The disadvantage of this approach is the considerable complexity and duration of the required tests. The aim of the work is to develop a calculation methodology for finding the content of sand in the normal-weight concrete, taking into account the optimality criteria given. Based on the well-known theoretical concepts, the design equations are substantiated for...

Dynamic stability of the lattice truss of the bridge taking into account local oscillations

Andrey Indeykin, Sergei Chizhov, Ekaterina Shestakova, Anatoly Antonyuk, Sergey Evtukov, Nikolay Kulagin, Vladimir Karpov & Dmitriy Golitsynsky
The carrying capacity of the railway and the service life of artificial structures primarily depend on the operational category of the structure and the dynamic state: dynamic stability, the condition that dangerous vibrations do not appear, and the dangerous resonance of the amplitude of the oscillations. Studies on the dynamics of railway bridges have gained relevance in connection with the new construction and reconstruction of bridges of high-speed and high-speed railroads. When choosing the restoration...

Deformation compatibility of masonry and composite materials

Vladimir Bespalov, Deniz Ucer, Ildus Salmanov, Israfil Kurbanov & Svetlana Kupavykh
Fiber Reinforced Polymers (FRP) are commonly used nowadays for strengthening deteriorated structures. The purpose of this research was to determine the combined behavior of masonry walls and reinforcing meshes together, according to their deformation characteristics. A sample wall with average masonry parameters and seven different common polymer nets on them were modelled in Abaqus Software. Moreover, a case study wall was also modelled according to the strength values obtained from direct testing of a demolished...

Quasistaticity of the process of dynamic strain of soils

Karim Sultanov, Pavel Loginov, Sabida Ismoilova & Zulfiya Salikhova
Mechanical characteristics of soil under static and dynamic strains are determined experimentally. Their accuracy and reliability depends on quasi-static nature of strain process in soil. The independence of experimental results on the wave processes is ensured. Laboratory devices of dynamic loading (DDL) have been used to determine the laws of dynamic strain and mechanical characteristics of soil. The quasi-static nature of strain process in soil on DDL is achieved solving the wave problem corresponding to...

Method of forecasting the effectiveness of cationic bitumen emulsions

Svetlana Shekhovtsova, Aleksey Korotkov & Marina Vysotskaya
Approbation of the procedure for predicting the production of effective bitumen emulsions at the stage of water phase preparation and also predicting the compatibility of the mineral aggregate and the surface-active substance used to emulsify the bitumen was carried out. As criteria characterizing the optimal composition of water phases, the following indicators were proposed: the surface tension of the water solutions under investigation and the wetting contact angle. The study of the dynamics of changes...

Метод расчета периода контроля оборудования инженерно-технических систем

Владимир Стальевич Солдатенко, Владимир Александрович Смагин, Ярослав Николаевич Гусеница, Василий Иосифович Гера & Тамара Николаевна Солдатенко
Рассматривается модель и процедура оптимизации периодов контроля и профилактических мероприятий применительно к оборудованию инженерно-технических систем. Данный подход реализуется на основе выполнения условия минимума средних потерь целевого использования оборудования. Указанные потери возможны из-за неоптимальной периодичности контроля и профилактики элементов инженерно-технических систем. В статье рассматривается подход, используемый в теории информации для минимизации снижения ценности информации по причине перерывов при ее передаче. Особенностью предложенной подхода является использование целочисленного квантования межконтрольных интервалов и учет случайной продолжительности периодов эксплуатации оборудования....

Функционал дополнительной энергии для анализа устойчивости пространственных стержневых систем

Юрий Яковлевич Тюкалов
Рассматривается решение задач устойчивости пространственных стержневых систем методом конечных элементов в напряжениях. Предлагаемая методика основывается на сочетании функционала дополнительной энергии и принципа возможных перемещений, используемого для построения уравнений равновесия узлов конечно-элементной сетки. После дискретизации предметной области, решение задачи сводится к поиску минимума функционала дополнительной энергии деформации при наличии ограничений в виде системы линейных алгебраических уравнений равновесия узлов. Уравнения равновесия включаются в функционал при помощи множителей Лагранжа, которыми являются перемещения узлов. Получены разрешающие уравнения для статического...

Method for noise calculation under specular and diffuse reflection of sound

Botir Giyasov, Vladimir Ledenyov & Irina Matveeva
Selection and designing of noise protection aids in industrial buildings require numerous calculations of energy characteristics typical for noise fields of their facilities. The efficiency of designed soundproof measures is relying on their accuracy. The degree of accuracy is defined by recording completeness in the method of measurement of factors, which affect the processes of noise fields in buildings. One of these factors is the type of sound refection from barriers. The analysis of reflected...

Residual resource of a one-storey steel frame industrial building constructed with bridge cranes

Tatiana Zolina & Pavel Sadchikov
The scheme of an integrated approach to the study of changes in the stress-strain state of the frame one-story industrial building constructed with bridge cranes, caused by accumulation of damage caused during the operation. The algorithm has been developed for estimating and predicting the residual resource of a production facility on the basis of processing the results of a series of surveys. It allows to obtain the values of reliability indicators in the correlation approximation...

Productivity of microalgae as biofuel for bioadaptive systems of facades

Ekaterina Zalata, Iurii Shavrov, Kseniya Strelets & Maria Emelyanova
Microalgae are one of the promising fuel sources and many specialists associate it with the future of alternative energy. A promising area of application of photobiological devices is their conjugation with the architectural covers of a building and formation of bio-adaptive facades. The determining criteria for the organization of the microalgae biomass production process in the facade structure is solar radiation, ratio of light and dark growth phase and ambient temperature. The goal of this...

The interaction between the kaolinite or bentonite clay and plasticizing surface-active agents

Pavel Bulanov, Lenar Mavliev, Yevgeniy Vdovin & Eduard Yagund
The influence of a number of superplasticizers of various chemical bases on the physical and technical properties of clay soils has been studied. Model soils are considered as clay soils: kaolin clay with kaolinite mineral content up to 95 %, bentonite clay with montmorillonite content up to 70%. The greatest increase in the physical and technical properties of clay soils is achieved when they are modified by a polycarboxylate superplasticizer, which is due to adsorption...

The stress state of a tank shell in the group under wind load

Volodymyr Mushchanov, Hanna Zubenko & Maxim Tsepliaev
The distribution of the wind flow has been studied and its effect on the stressed state of the shell of a steel vertical cylindrical tank. Variants of wind pressure were considered for one tank and for a group of tanks. Aerodynamic coefficients are obtained for the considered variants in the SolidWorks software package. A physical experiment on a reduced tank model in a wind tunnel was conducted to verify the coefficients obtained. The stresses in...

Computational modelling of stiffness and strength properties of the contact seam

Anatoliy Lukashevich
The problem of contact interaction of structures taking into account the deformation and strength properties of the contact seam material is considered. To discretize the contact layer, frame-rod contact finite elements (CFE) are used, by means of which the physical properties of the seam material (initial strength, line and nonlinear deformability) are modelled. By means of CFE are also modelled various contact conditions – separation, clutch, friction-sliding, etc. On the base of the proposed discrete...

Rheological behavior of 3D printable cement paste: criterial evaluation

Galina Slavcheva & Olga Artamonova
The extrudability and firm stability are the criterial rheological characteristics of building 3D printable mixtures. From the point of view of classical rheology of disperse systems, the theoretical analysis of the rheological behavior of a cement paste has been analyzed for all stages of 3D printing process. Apparently both the theoretical analysis criteria and technological tools to control rheological behavior of a 3D printable mixture have been justified. The squeezing test is used in the...

Water permeability of the polymer screen with a system of slits of hydraulic structures

Yuri Kosichenko & Oleg Baev
The calculation of water permeability through a system of defects (long narrow slits in the junctions) in the screen is considered based on the filtration model. Its structural layout and description of the model main elements are given. The solution is carried out for the plane formulation of the problem by the methods of the filtration theory using the method of conformal mappings and the velocity hodograph method. A distinctive feature is the study of...

Ultra-light hybrid composite wood-polymer structural materials in construction

Aleksandr Rassokhin, Andrey Ponomarev & Oleg Figovsky
In the 21st century, wood construction is again widespread. Industrial wood ceased to be perceived as a material for household buildings and low-rise rural houses and began to be used in the construction of large-span, high-rise and unique buildings and structures. The paper analyzes the use of wood for the construction of large-span, high-rise and unique buildings and structures. The results of experimental studies of hollow wooden parts, developed by the authors, impregnated with epoxy...

Expanding cements hardening within the limited deformations conditions

Igor Kharchenko, Andrey Pustovgar, Stanislav Pashkevich, Aleksey Eremin, Irina Ivanova, Yuri Bazhenov & Aleksey Kharchenko
The features of expanding cement strength and structure formation at different constrained deformation conditions were studied (without constraint of deformations, uniaxial constraint of deformations, biaxial constraint of deformations, and triaxial constraint of deformations). The study was conducted for three doses of 5 %, 15 % and 25 % of expander on the calcium sulfoaluminate basis in Portland cement of CEM 42.5 mark. For experimental data interpretation in the analysis of structure and phase composition, the...

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