33407 2304-6295 Construction of Unique Buildings and Structures 8 93 2020 1-105
RAR RUS 9301-9301 12039592100 0000-0003-4283-0400 South Ural State University Korolev Aleksandr Sergeevich korolev@sc74.ru
Chelyabinsk, Russian Federation
 56607130900 0000-0002-1286-3888 South Ural State University Vakhitov Maksim Grigorevich vakhitovmg@susu.ru
Chelyabinsk, Russian Federation
 55816588400 0000-0002-9948-5145 South Ural State University Klygach Denis Sergeevich klygachds@susu.ru
Chelyabinsk, Russian Federation
 6603541949 0000-0002-3368-9858 South Ural State University Zherebtsov Dmitry Anatolevich zherebtsov_da@yahoo.com
Chelyabinsk, Russian Federation
 57190961036 0000-0003-4021-003X South Ural State University Mishnev Maxim Vladimirovich mmv2004@list.ru
Chelyabinsk, Russian Federation
 Dry mixes for microwave protection covering The research aimed to create highly effective radioprotective mixtures based on graphite particles and dielectric particles of expanded pearlite for multilayer coatings with high radio absorption rates and radio reflection in the layers. The study's object was a multilayer radio-absorbing plaster coating based on graphite particles and dielectric particles of expanded pearlite. Measurements of the radio transmission coefficient and the radio reflection coefficient of a multilayer absorbing plaster coating were carried out in the frequency range from 2 to 8 GHz in an anechoic chamber Rainford EMС3. The assessment results of the radioprotective properties have confirmed the high efficiency of using dry mixtures containing fillers with electromagnetic properties. The mixtures made on an aggregate with electromagnetic properties have a high shielding capacity. Their high radio-absorbing ability distinguishes mixtures combining aggregates with electromagnetic properties and porous dielectric aggregates. Forming two-layer coatings, in which the base layer is shielding, and the top layer is absorbing, has proven effective. Two-layer coatings allow to achieve a synergistic effect, in which the coating has both high shielding and absorbing properties. Based on the developments carried out, a radioprotective plaster mixture Ceramix-T IKUR was created. The plaster mixture was successfully used in the creation of alternative measuring sites, including at the Federal State Unitary Enterprise Production Association MAYAK, Chelyabinsk region, and others. 10.18720/CUBS.93.1 69 Dry mixes Microwave/Radiowave defense Microwave/Radiowave reflecting/ecraning Microwave/Radiowave absorbing Electromagnetic Dielectric Coating Plaster Putty https://unistroy.spbstu.ru/article/2020.93.1/ 9301.pdf
RAR RUS 9302-9302 57190961036 0000-0003-4021-003X South Ural State University Mishnev Maxim Vladimirovich mmv2004@list.ru
Chelyabinsk, Russian Federation
 12039592100 0000-0003-4283-0400 South Ural State University Korolev Aleksandr Sergeevich korolev@sc74.ru
Chelyabinsk, Russian Federation
 0000-0002-4879-6699 South Ural State University Zadorin Aleksandr Aleksandrovich zadorinaa@susu.ru
Chelyabinsk, Russian Federation
 0000-0003-0276-957X South Ural State University Khoroshilov Nikita Andreevich
Chelyabinsk, Russian Federation
 Based on the hybrid hot-curing epoxy binder fiberglass and evaluation of its effectiveness in load-bearing chimneys The paper presents the results of experimental and theoretical studies of polymer binder based on a hot-curing epoxy resin filled with microparticles of micro marble (micro calcite); the binder classified as hybrid organo-mineral. The results of evaluating several epoxy binders' thermal stability filled with micro marble during prolonged exposure in the temperature range from 160 °C to 300 °C are presented. The modulus of elasticity of an unfilled and filled with micro marble epoxy binder was investigated using the three-point bending method at temperatures up to 130 °C; comparing these properties with a theoretical prediction method on FE homogenization using the Design Modeler module of the Ansys package was carried out. A three-point bending method at temperatures up to 180 °C was used to study the elastic modulus of fiberglass on the basis of unfilled and filled with micro marble binder. An assessment of the effectiveness of the use of based on hybrid organo-mineral binder fiberglass in the structures of load-bearing chimneys under thermo-mechanical effects is carried out. 10.18720/CUBS.93.2 69 Polymer composite Hybrid composite Fiber-reinforced plastics Hot-curing epoxy resins Thermal stability Elastic modulus Chimney Ansys Material Designer Finite element based homogenization https://unistroy.spbstu.ru/article/2020.93.2/ 9302.pdf
RAR RUS 9303-9303 0000-0002-4107-2452 Belarusian-Russian University Maskalkova Yuliya Georgievna julia43@tut.by
Mogilev, Republic of Belarus
 0000-0001-8854-5408 Belarusian-Russian University Rzhevutskaya Valeriya Andreevna valeriarzhevuckaya@gmail.com
Mogilev, Republic of Belarus
 The Effective Reinforcement Ratio of Expanded Clay Concrete by Polypropylene Fiber The object of research is the dispersed reinforcement with polypropylene fiber of expanded clay concrete produced by using local raw materials. The purpose of this study is to select the optimal reinforcement ratio of expanded clay concrete containing polypropylene fiber. It is also proposed to investigate which variation of adding fiber is most effective (as an admixture with a constant content of the binding material or instead of cement mass). Method. Polymer fiber reinforcement should be added to the dry mix, thoroughly mix all the components and only then add water to the mix. In case of non-observance of this condition, it is impossible to achieve a homogeneous distribution of fiber in the hardened concrete, and therefore, the effect of disperse reinforcement will be reduced to zero. Results. As a result of investigations, special attention must be paid to the correct preparation technology at the time of concrete mixture preparation. Otherwise, the polymer fiber introduction will have a negative effect. In this case, the coarse aggregate use is a significant condition. The secant modulus of elasticity will decrease by more than two times if the diameter of expanded clay grains increases. It is recommended to use expanded clay gravel with smaller fractions in accordance with investigations. The maximum and minimum allowable content of polypropylene fiber are 0.5–1.5 %. The compressive cube strength increase of expanded clay concrete by polypropylene fiber is achieved by this allowable content in comparison with unreinforced expanded clay concrete with a similar concrete mixture. The most effective is reinforcement ratio of 1.5 %, and the maximum compressive strength increase by 14 %. The polypropylene fiber should be added in a percentage ratio depending on the cement mass with constant cement content in accordance with investigations. The fiber introduction instead of cement by mass negatively affects the strength characteristics. 10.18720/CUBS.93.3 69 Lightweight concrete Expanded clay concrete Compressive cube strength Dispersed reinforcement Polypropylene fiber Reinforcement ratio Modulus of elasticity Aggregate diameter https://unistroy.spbstu.ru/article/2020.93.3/ 9303.pdf
RAR RUS 9304-9304 57190856106 0000-0002-3583-5978 Riga Technical University Zajacs Aleksandrs
Riga, Latvia
 0000-0002-4487-5699 Riga Technical University Zeiza-Seļezņova Anastasija
Riga, Latvia
 0000-0003-2532-3300 Riga Technical University Rusovs Dmitrijs
Riga, Latvia
 Impact of Flue Gas Recirculation on the Efficiency of Hot-water Boilers The topicality of the work is related to the fact that the combustion processes of various fuels, such as heat production, produce emissions that are harmful to the environment. The combustion of fossil fuels produces nitrogen oxides, which are about 10 times more dangerous than carbon monoxides. There are different methods to reduce nitrogen oxides emissions and one of effective methods is flue gas recirculation. Despite efficiency, flue gas recirculation has an impact on the efficiency of the boiler. The efficiency coefficient for the hot-water boiler was calculated with and without flue gas recirculation. The calculation with flue gas recirculation leads to a slight reduction in the efficiency factor, herewith flue gas recirculation reduced emissions of nitrogen oxides by 44,5%. 10.18720/CUBS.93.4 69 flue-gas recirculation natural gas boiler nitric oxide https://unistroy.spbstu.ru/article/2020.93.4/ 9304.pdf
RAR RUS 9305-9305 G-2929-2018 56227381900 0000-0003-2673-4566 Peter the Great St. Petersburg Polytechnic University Sergeeva (Nemova) Darya Viktorovna darya0690@mail.ru
St. Petersburg, Russian Federation
 0000-0003-2626-2626 Peter the Great St. Petersburg Polytechnic University Kotov Evgeny Vladimirovich ekotov.cfd@gmail.com
St. Petersburg, Russian Federation
 0000-0001-7173-5897 Peter the Great St. Petersburg Polytechnic University Daurov Zaur Soslanovich
St. Petersburg, Russian Federation
 57190865804 0000-0002-8136-3246 Peter the Great St. Petersburg Polytechnic University Olshevskiy Vyacheslav Ianushevich 79119199526@yandex.ru
St. Petersburg, Russian Federation
 Energy Efficiency of Closed Cavity Fasades The number of high-rise buildings with enclosing structures made of glass is growing rapidly every year. High transparency of buildings is becoming one of the reasons of high-energy consumption. The problem of energy saving in glass structures is becoming more and more urgent. The innovative double-skin glass facade system has proven to be energy efficient in European countries. In the future, this design will significantly reduce the energy load of the building. The object of research is an innovative systems Сlosed cavity facade (CCF). The purpose of this work is to analyze the energy efficiency of the innovative system Closed cavity facade. The energy consumption of a building with classic glazing (a) and Сlosed cavity facades are considered. Method. In the analytical study, to determine the unknown characteristics of the closed cavity facade systems, the ANSYS software package was used - a universal system of finite element analysis.  The services Autodesk Insight and Autodesk Green Building Studio estimated building energy consumption, electricity consumption by month, carbon dioxide emissions, total energy costs for the year and for the life cycle, etc. Results. In the analytical study, the classification of double facades by the ventilation method and by the geometry of the inter-contour space is presented, the main advantages are revealed. As a result of mathematical modelling, the calculated heat transfer resistance was determined for the Facade with a closed cavity Rcalc = 1.93 m2∙K/W. The result for the Closed Cavity Facade system was 35.7% more efficient than classical glazing. The average energy consumption for a building with classic glazing was determined - 374 kW / m2 / year with classic glazing and the average energy consumption for a building with a closed cavity facade - 219 kW / m2 / year. The difference in power consumption is 41.4%. 10.18720/CUBS.93.5 69 Heat-gravitational convection Heat and mass transfer Constructive energy saving Energy efficiency Ventilated air gap Fluid mechanics of air flows Sustainable building Building envelop Double-skin facade Сlosed cavity facade https://unistroy.spbstu.ru/article/2020.93.5/ 9305.pdf
RAR RUS 9306-9306 6506150284 0000-0003-1139-3164 Moscow State University of Civil Engineering Sainov Mikhail Petrovich mp_sainov@mail.ru
Moscow, Russian Federation
 0000-0003-2806-9635 Moscow State University of Civil Engineering Kotov Filipp Viktorovich
Moscow, Russian Federation
 57204501403 0000-0003-4277-7128 Moscow State University of Civil Engineering Soroka Vladislav Borisovich
Moscow, Russian Federation
 Thermo-stressed state of rockfill dam concrete face at reservoir impoundment In Russia and China there considered the plans of constructing concrete face rockfill dams (CFRD) in the regions whose climate is characterized by considerable drops of temperature. Therefore, the issue about the role of thermal effects in formation of stress-strain state (SSS) of rockfill dam concrete face becomes urgent. We studied the impact on concrete face SSS without cooling effect of water during the reservoir impoundment. Materials and methods. A 100 m high dam was studied whose face was 0.5 m thick. Numerical modeling of the dam behavior was conducted with the aid of the finite element method. At first, the non-stationary temperature regime of the dam was studied at the reservoir impoundment. It was assumed that the rate of the water level rise comprised 1 m a day and water temperature was 20°С less than the dam temperature. Then the temperature distribution in the face was used for calculation of thermal forces in it. SSS analyses were conducted for two cases: with consideration of thermal forces and without it. Results. Analyses showed that by the moment of the reservoir impoundment completion the face temperature regime at a depth of more than 5÷10 m is close to the steady regime. It is characterized by nearly uniform cooling of the face, which results in appearance of additional tensile longitudinal force approximately 1 MPa in this part of the face. In the zone of water edge the thermo-stressed state of the face is much more unfavorable. The temperature regime of this zone is characterized by non-uniform distribution of temperatures along the face thickness and height; it intensively varies within several days after the reservoir impoundment completion. The most dangerous is the initial time interval when the zone of concentration of high tensile stresses (more than 3 MPa) appears in the water edge zone in the face upstream part. Conclusions. Cooling of the face at the reservoir impoundment is dangerous for the face concrete strength. At CFRD construction in severe climatic conditions it is reasonable to arrange heat insulation of the face upstream part. 10.18720/CUBS.93.6 69 Concrete faced rockfill dam Temperature regime Stress-strain state Thermo-stressed state Reservoir impoundment Strength https://unistroy.spbstu.ru/article/2020.93.6/ 9306-1.pdf
RAR RUS 9307-9307 P-3728-2017 57194112309 0000-0001-6184-2365 Vyatka State University Tyukalov Yury Yakovlevich yutvgu@mail.ru
Kirov, Russian Federation
 Optimal Shape of Arch Concrete Block Bridge The object of research is arched bridges made of concrete blocks backfilled with soil. The aim of the study was to develop a technique for determining the arch bridge's optimal shape in order to ensure the required size of the compressed cross-sectional zone at any automobile load position. The calculation takes into account the horizontal and vertical pressure of the backfill soil and the arch dead weight. The concrete blocks can have variable heights. Method. To solve the problem in a physically nonlinear formulation, the stepwise loading method and the possible stress states principle in increments were used. The solution was constructed by the finite element method based on piecewise constant approximations of the moments and forces. The nodes equilibrium equations obtained using the possible displacements principle are added to the additional energy functional written in increments form. The nodes vertical and horizontal displacements are accepted as possible displacements. When determining the required dimensions of the arch, the automobile load all possible positions are considered. Results. The optimum geometric parameters have been determined for an arch bridge with a span of 12 meters. The destructive automobile load value is determined. For the design load, the obtained internal moments and forces are compared with the ones calculated by the program based on the finite element method in displacements. 10.18720/CUBS.93.7 69 Arch bridge Finite element method Concretes Optimal shape Numerical methods Cracks https://unistroy.spbstu.ru/article/2020.93.7/ 9307(1).pdf