75504 2712-8172 7 83 2018 1-234

RAR RUS 3-11 Vladimir State University named after Alexander and Nikolay Stoletovs Gribanov Aleksei panecito@bk.ru Vladimir State University named after Alexander and Nikolay Stoletovs Roshchina Svetlana rsi3@mail.ru Vladimir State University named after Alexander and Nikolay Stoletovs Popova Marina popovamv@bk.ru Vladimir State University named after Alexander and Nikolay Stoletovs Sergeev Michael sergeevmichael@inbox.ru Laminar polymer composites for wooden structures The lack of a clear regulatory framework governing the use of polymer composites to strengthen wooden structures, stimulates the conduct of numerous studies in this area. An important task is to obtain reinforcing materials with the best physico-mechanical and operational parameters. The choice of the type of curing adhesive has a great influence to characteristics of polymer composites such as viscoelastic parameters of the material, adhesion properties on the contact surfaces, the presence of internal defects, etc. The paper describes a method for determining the physicomechanical characteristics of a composite material based on experimental studies. The stand, test samples and the pattern array of tensometric sensors for testing according to Russian State Standard GOST R 56800-2015 "Polymer composites. Determination of tensile properties of unreinforced and reinforced materials have been presented. Dependences of stress-strain, modulus of elasticity, Poisson's ratio, tensile strength for laminate polymer composite have been obtained. Comparative analysis of the obtained results for various adhesive compositions has been performed. According to the results of experimental studies, it was found that the physicomechanical characteristics of polymer composites based on epoxy matrix are higher than those of polyurethane matrix composites due to uniform filling of the filler volume, as well as better wettability of the reinforcing fibers. In conclusion, the article draws conclusions about the effect of the adhesive composition on the mechanical characteristics of the obtained composites have been made, relevance and applied significance of the investigation for strengthening the compressed-flexural elements of wooden structures has been justified. 10.18720/MCE.83.1 polymer composites glass fiber reinforced polymer (GFRP) fiber glass composites curing matrix elastic modulus contact molding vacuum infusion compressedflexural elements wood https://engstroy.spbstu.ru/article/2018.83.1/ 01.pdf

RAR RUS 12-23 Kazan State University of Architecture and Engineering Zamaliev Farit zamaliev49@mail.ru Kazan State University of Architecture and Engineering Zakirov Marat z_marat_a@mail.ru Stress-strain state of a steel-reinforced concrete slab under long-term This article explores the evaluation of the stress-strain state of steel reinforced concrete slabs under the action of long-term loads. The technique of computer simulation for the performance evaluation of steel reinforced concrete slabs under short-term and long-term loads and the results of numerical studies are shown. A unit for long-term tests has been prepared based upon the numerical studies. The mounting locations of instruments for measuring vertical displacements, the label diagram of sensors of strains in steel reinforced concrete test structures are given. The measurement results are summarized in tables and graphs. The analysis of the results of full-scale tests is given as are comparisons with numerical experiments’ data. Analytical expressions for the calculation of steel reinforced concrete slabs for long-term loads taking into account the creep of concrete are given. 10.18720/MCE.83.2 steel reinforced concreteslab numerical experiments full-scale tests stresses deflections comparisons https://engstroy.spbstu.ru/article/2018.83.2/ 02.pdf

RAR RUS 24-37 Poltava National Technical Yuri Kondratiuk University Pichugin Sergii pichugin.sf@gmail.com Reliability estimation of industrial building structures The article is devoted to solving the problem of the reliability of industrial building structures: crane and roof beams, columns, redundant building systems. For this aim, the probabilistic method of structural reliability estimation is developed after the criterion of bearing strength, in which the main component of structure reliability is faultlessness. The method takes account of the random loads and material strength, loads joint action, the specific character of work and failure elements, nodes and the whole structure as well. For the ground of method, the large amount of statistic results on crane load is examined for the bridge cranes of the different types. A large amount of wind and snow meteorological data is collected for the territory of Ukraine. Stationary probabilistic model of crane load and quasistationary model of the snow and mean wind load are substantiated. The most widely spread probabilistic presentations of random loads are observed. They are as follows: stationary random process and its absolute maxima, random sequence of independent and correlated loads, discrete presentation and extreme model. It was deduced that the redundant structure reliability estimation is a very complicated problem as depends upon the system complexity. The method of states, a probabilistic method of ultimate equilibrium and logic and probabilistic method are developed for solving this problem. On the base of the determined method, the numerical reliability computations of a wide range of industrial building structures are realized. It is shown that the structures have quite different levels of reliability. In particular, the light roof structures are not reliable enough being under the great influence of snow load. At the same time, the Design Code allows over-estimation of reliability for industrial columns. The estimation of industrial redundant structures with a different degree of redundancy is obtained on the base of developed approach. It gave the possibility to evaluate the high safety level of redundant structures in comparison with separate members and statically determined structures. With regard to mentioned results, it is recommended to correct some load factors, a combination factor and a factor for model uncertainties of the Design Codes of structures and loads. 10.18720/MCE.83.3 construction building structure reliability failure probabilistic method load redundant system https://engstroy.spbstu.ru/article/2018.83.3/ 03.pdf

RAR RUS 38-48 JSC "Alekseevskdorstroy" Bulanov Pavel pavel.bulanov1991@yandex.ru Kazan State University of Architecture and Engineering Ermilova Elizaveta lizabeta_91@list.ru Kazan State University of Architecture and Engineering Mavliev Lenar lenarmavliev@yandex.ru Structure and mineral composition of soil-cement with complex additive The effect of the polycarboxylate ether and the complex hydrophobic-plasticizing additive on the structure, phase and mineral composition of cement based on polymineral clay with content of relict minerals more than 85 % (52.49 % of quartz) was studied. As research methods chosen X-ray diffraction pattern, differential scanning calorimetry and scanning electron microscopy. The regularities of the effect of the complex hydrophobic-plasticizing additive based on polycarboxylate ether and octyltriethoxysilane on the formation of cement hydration products in a strengthened clayey soil are established. Changes in structure and composition include the following: the formation of a strong skeleton of the crystallization phase due to the increase in the number of hydrated new formation in the form of low-basic hydrated calcium silicate and ettringite, decrease in portlandite content, as well as an increase in the amount of amorphous phase (up to 16 %) in the form of tobermorite gel filling intercrystalline spaces. In soil-cement hydrated silicate calcium are formed in an amount of more than 4 % and ettringite in an amount of more than 7 %, the amount of portlandite reduced by 46 %. The result of modification of the complex hydrophobic-plasticizing admixture of soil-cement, a denser and homogeneous structure with a pronounced "overgrowth" of the pores formed by gel-like hydrated calcium silicate is formed, which are deposited in a large amount on the minerals of the strengthened soil. 10.18720/MCE.83.4 soil-cement polycarboxylate ether octyltriethoxysilane X-ray diffraction pattern differential scanning calorimetry ettringite low-basic hydrated calcium silicate structure https://engstroy.spbstu.ru/article/2018.83.4/ 04.pdf

RAR RUS 49-61 Donbas National Academy of Civil Engineering and Architecture Mushchanov Volodymyr volodymyr.mushchanov@mail.ru Donbas National Academy of Civil Engineering and Architecture Zubenko Hanna zubienko_anna@mail.ru Donbas National Academy of Civil Engineering and Architecture Tsepliaev Maxim m.s.sepliaev@donnasa.ru The stress state of a tank shell in the group under wind load 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 the tank shell were determined by the finite element method using the SCADOffice calculation complex. The result revealed differences normative distribution of wind pressure from the pilot for single tank and located in the band. The most unfavorable version of the distribution of wind pressure for the tank located in the group was determined. The stress-strain state of the tank shell is compared under the normative and experimental wind load for the most unfavorable variant. 10.18720/MCE.83.5 wind tunnel aerodynamic coefficient vertical cylindrical tank https://engstroy.spbstu.ru/article/2018.83.5/ 05.pdf

RAR RUS 63-72 Polzunov Altai State Technical University Ovcharenko Gennady egogo1980@mail.ru Polzunov Altai State Technical University Gilmiyarov Danil egogo1980@mail.ru Strength and phase composition of autoclaved material: an approximation The purpose of this work was to identify the relationship between the phase composition and strength of autoclaved pressed stone from a mixture of lime and ash of CHP in the presence of Na2SO4. From these mixtures are made such building materials as silicate brick and blocks from autoclaved cellular concrete. The phase analysis of the autoclaved samples was carried out by X-ray and thermal methods. It was found that the mixtures studied after autoclaving for 8; 50 and 100 hours at 0.8 MPa isotherm with no addition or with 1 and 2% Na2SO4 is represented by gel-like phase C-A-S-H, aluminum substituted tobermorite, hydrogarnet katoite. Adding of 1 and 2% Na2SO4 makes no qualitative change in phase composition, but significantly redistribute the phase composition and increase the rate of phase formation. Thus 2 % Na2SO4 contributes to a substantial increase in the synthesis of Al-tobermorite, but reduces the C-A-S-H phase formation. Katoite hydrogarnet content remains unchanged. The degree of hydration of the composition with 2% Na2SO4 for 8 hours of autoclaving is the same as for 100 hours of treatment without an additive. This increases the strength of the material by 1.65 times with the same 8 hour steaming time. Strength of the stone is always directly proportional to the content of a gel C-A-S-H phase. Its content is proportional to the number of Al-tobermorite in non-additional mixtures, but does not correspond to the content of tobermorite in compositions with addition of 2 % Na2SO4. Keywords: autoclaved building materials, lime-fly ash mixtures, Na2SO4 addition, phase composition, strength of the stone, interrelationships. 10.18720/MCE.83.6 autoclaved building materials lime-fly ash mixtures Na2SO4 addition phase composition strength of the stone interrelationships https://engstroy.spbstu.ru/article/2018.83.6/ 06.pdf

RAR RUS 73-82 Surgut State University Snigireva Vera snow-vera@mail.ru Surgut State University Gorynin Gleb ggorynin@list.ru The nonlinear stress-strain state of the concrete-filled steel tube structures The article is devoted to the mathematical modeling of the nonlinear stress-strain state of the concrete core in the concrete-filled steel tube structures. The paper uses a nonlinear diagram of concrete deformation under compression, which consists of two straight sections. In addition, the increase in the Poisson's ratio with increasing longitudinal deformations is taken into account. The article discusses two types of concrete-filled steel tube structures: the traditional concrete-filled steel tube column and the concrete column in steel tube cage. It is established that when the traditional concrete-filled steel tube column is loaded, the steel tube break contact with concrete core. This is the latent defect in such structures. The concrete column in steel tube cage does not have this defect. Concrete is acted to the three-dimensional compression here. It is concluded that taking into account the nonlinear behavior of concrete leads to the increasing of the calculated load-bearing capacity of the concrete column in the steel tube cage. In addition, change in the Poisson’s ratio of concrete leads to the increasing of the load-bearing capacity too. 10.18720/MCE.83.7 concrete-filled steel tube structures nonlinear concrete deformation diagram concrete column in a steel cage https://engstroy.spbstu.ru/article/2018.83.7/ 07.pdf

RAR RUS 83-89 57190161363 0000-0002-2328-6238 Ogarev Mordovia State University Nizina Tatyana nizinata@yandex.ru National Research Moscow State University of Civil Engineering Sokolova Julia inep_s@mail.ru Ogarev Mordovia State University Chernov Alexey lhms13@yandex.ru Ogarev Mordovia State University Nizin Dmitrii nizindi@yandex.ru Ogarev Mordovia State University Kanaeva Nadegda aniknadya@yandex.ru Filled epoxy composites based on polyfraction microcalcite The effect of the polyfractional micromarble introduction on the change in the physical and mechanical characteristics of polymer composites based on low-viscosity epoxy binders has been studied. Evaluation of changes in compressive strength and tensile strength in bending of epoxy composites samples containing micromarble of three different fractions, depending on the degree of filling, was carried out. Using the method of least squares, mathematical dependences of the epoxy composites strength characteristics on the type of used micromarble and the degree of filling have been obtained. The analysis of isolines and Gibbs-Rosebom triangular diagrams allowed to determine the composition of the polyfractional filler, the composites on the basis of which have the greatest strength characteristics. Polymer composite containing a mixture of micromarble of different fractions in the amount of 80 % of the maximum filling level and having an increased compressive strength (up to 40 %) and close to the limit tensile strength during bending (decrease by no more than 10 %) compared to the unfilled composition epoxy polymer was obtained. The mechanical properties and the high filling degree of the obtained composite indicate the possibility of using micromarble as an effective filler for epoxy polymers, which is also confirmed by the achieved substantial economic effect. 10.18720/MCE.83.8 epoxy composites filler micromarble degree of filling ultimate strength at compression ultimate bending tensile strength isolines triangular Gibbs-Roseboom diagrams https://engstroy.spbstu.ru/article/2018.83.8/ 08.pdf

RAR RUS 92-101 Peter the Great Saint Petersburg Polytechnic University Bonivento Bruges Jose ing.joseboniventob@gmail.com

Polytechnicheskay, 29

Peter the Great Saint Petersburg Polytechnic University Vieira Gabriel gabriel.vieira@poli.ufrj.br

Polytechnicheskay, 29

Peter the Great Saint Petersburg Polytechnic University Revelo Orellana Diana Paola diana91pao@gmail.com

Polytechnicheskay, 29

Peter the Great Saint Petersburg Polytechnic University Togo Issa issatogo@mail.ru

Polytechnicheskay, 29

Parameter of thermal resistance of bamboo multilayer wall With the increasing of problems related to air pollution and rising of the mean temperature around the globe, new solutions must be investigated in order to diminish the magnitude of such environmental issues. Therefore, the appliance of bamboo in the construction can be one of the solutions. Even though, this grass does not present mechanical or thermal homogeneity, its high sustainability (CO2 reducer, highness and fast speed of growth), strength and hollowed cylindrical morphology make it an option in the construction sector. As an energy-efficient material, this woody grass can have a positive thermal performance due to the presence of air cavities, however, its rounded nature influence to a nonhomogeneous performances in the surface and interior. The literature about the thermal performance of this element as building envelopment is reduced. Thus, the aim of this research is to analyse the thermal performance of a one, two and three bamboo layers, placing them in a way to mitigate the heat leaking and improving the thermal resistance. It is analysed numerically and through a simulation developed in THERM 7.5 Finite Element Simulator. As a result, two line of bamboo is convenient as a material construction with U-Value of 1.4 W/m².K, but three layers is recommended to mitigate the presence of thermal bridges. The results obtained leads to a different approach and suggests further analysis for different parameters. 10.18720/MCE.83.9 bamboo guadua thermal resistance thermal transmittance (U-Value) https://engstroy.spbstu.ru/article/2018.83.9/ 09.pdf

RAR RUS 102-113 K-1945-2018 6506225641 0000-0002-8463-9965 Kazakhstan Highway Research Institute Teltayev Bagdat bagdatbt@yahoo.com

2A, Nurpeissov Street, Almaty, Republic of Kazakhstan, 050061

School of Civil Engineering, Beijing Jiaotong University Liu Jiankun liujiank@mail.sysu.edu.cn Kazakhstan Highway Research Institute Suppes Elena suppes08@mail.ru Distribution of temperature, moisture, stress and strain in the highway The paper analyzes regularities for the distribution of temperature, moisture, stresses and strains in pavement and subgrade of the highway, located in northern part of Kazakhstan, within one year, especially during cold season. Distribution of temperature and moisture has been determined experimentally with the use of special sensors. Stresses and strains have been calculated with the use of elastic multilayer semi-space model. It has been shown that the stiffness (elasticity modulus) of asphalt concrete layers and upper part of subgrade soil increases considerably during cold winter season: up to 18000 MPa and 10000 MPa respectively. All the components of stresses and strains vary considerably in points of pavement and subgrade during the annual cycle. Variations of pavement surface deflection and horizontal stress in the bottom asphalt concrete layer are of quasi harmonic nature, and horizontal strain in this point varies under the quasi bicyclic law. Horizontal stress during the cold season is a tensile one and has the biggest value, and during hot season it changes its sign and becomes the compressive one. Horizontal strain during the whole annual cycle remains only a tensile one. The biggest variations of stresses and strains occur in the upper part of subgrade. During cold season the vertical compressive stresses and strains are the minimal ones, and in the beginning of spring they are the maximal ones. 10.18720/MCE.83.10 pavement subgrade temperature moisture cold season freezing unfrozen water stress strain https://engstroy.spbstu.ru/article/2018.83.10/ 10.pdf

RAR RUS 114-125 Ogarev Mordovia State University Makeev Andrey tggi@rambler.ru Implementation of pulse heat supply for dependent connection of customers This article deals with organization of pulsed and fluctuating circulation of heat-carrying agent in separate sections of heat supply system with dependent connection of customers. These types of oscillatory motion of the heat-carrying agent are proposed to be carried out in a self-sustained operation on the basis of the hydraulic ram operation principle. The relevance of the subject-matter is determined by the influence of oscillating flows on the intensity of heat exchange processes and by the possibility of using the circuit design of hydraulic ram in order to improve energy efficiency of heat supply systems. Analysis of the technical solution of a single-fluid hydraulic ram is carried out and conditions for ensuring its possible operation in a closed hydraulic circuit are determined. A sequential transition is shown for the use of this water-lifting device in the heat supply system with dependent connection of customers for organization of pulsed and fluctuating circulation of the heat-carrying agent in its separate sections. The research results form a unified view of technical realization method of the vibrational circulation of the heat-carrying agent in a self-sustained operation in separate sections of the heat supply system with dependent connection of heat consumption systems. Taking into account the achievement of intensification of heat exchange processes in these conditions, self-cleaning of heat exchange surfaces and possible strengthening of pressure in the heat consumption system only at the expense of the available pressure of the heat network, it is concluded that application of the circuit design of the hydraulic ram in the heat supply system can be used to increase its energy efficiency. 10.18720/MCE.83.11 heat supply system heat supply network heat consumption system heat supply station shock unit fluctuating circulation of heatcarrying agent pulsing circulation of heat-carrying agent available head transformation https://engstroy.spbstu.ru/article/2018.83.11/ 11.pdf

RAR RUS 126-132 Riga Technical University Buka-Vaivade Karina karina.buka.vaivade@gmail.com 6508223358 Riga Technical University Serdjuks Dmitrijs Dmitrijs.Serdjuks@rtu.lv

1 Kalku Street, Riga LV-1658, Latvia

Riga Technical University Goremikins Vadims goremikins@gmail.com M-6585-2013 6508103761 0000-0002-1196-8004 Peter the Great Saint Petersburg Polytechnic University Vatin Nikolai vatin@mail.ru

Polytechnicheskay, 29

H-5843-2013 57205122537 0000-0002-8367-7927 Riga Technical University Pakrastins Leonids leonids.pakrastins@rtu.lv Suspension structure with cross-laminated timber deck panels Innovative suspension structure with prestressed cable trusses as the main load-bearing members was developed. Cross-laminated timber panels of the deck are placed to the bottom chords of the prestressed cable trusses. The structure with the deck panels placed to the bottom chord with the clearances and behaves in bending in the transversal direction only, and the structure with the deck placed without clearances and behaves in bending in the transversal direction and in compression in longitudinal directions, are considered. The suspended pedestrian-bicycle bridge with the span and width equal to 60 and 5 m correspondingly and loaded by the imposed load 5 kN/m2, was considered as an object of investigation. The optimization algorithm of the innovative suspension structure with cross-laminated timber deck panels was developed using the program ANSYS v12 optimization tools. Rational values of crosssection areas of suspenders, main load-bearing and stabilization cables were evaluated. It was shown, that placement of the deck panels without clearances, when the panels behave in compression in the longitudinal direction and in bending in transversal direction enables to decrease materials consumption by 25% in comparison with the case when the panels are placed with clearances and behave in bending in transversal direction only. 10.18720/MCE.83.12 prestressed cable truss crosslaminated timber deck panels experimental verification transformed section method suspension bridge https://engstroy.spbstu.ru/article/2018.83.12/ 12.pdf

RAR RUS 136-147 57189525518 0000-0002-7201-5979 Kostroma State University Vahnina Tatiana t_vachnina@mail.ru

Kostroma, Russia

16242836100 0000-0002-7295-8934 Kostroma State University Susoeva Irina i.susoeva@yandex.ru

Kostroma, Russia

Thermal-insulation boards from fibrous plant wastes and urea-formaldehyde binder The paper presents the results of laboratory research of indicators of composite thermal-insulation boards filled with irretrievable spinning flax and cotton. As the matrix of the composite used UF binder with various additives. UF binder has advantages and disadvantages: is cheaper but less waterproof than other synthetic binders. The work assessed the properties of the binder and the influence of the composition of the binder on the physical and mechanical properties of the thermal-insulating material. The IR spectrum of the binder, the dependence of the degree of curing of the UF binder on the type and proportion of the hardener additive are given. The results were obtained that the degree of curing and water resistance of the UF binder depends on the type and proportion of the hardener additive and the curing temperature. The physical and mechanical properties and the coefficient of thermal conductivity of the boards on the UF binder were determined. It is shown that the type of additive in the UF binder affects the physical and mechanical properties of thermal-insulation composite boards from spinning flax and cotton. The paper summarizes the results of the determination of the physical and mechanical parameters of boards from plant waste, and proposed a rational combination of factors for the production of composites. The type of additive in the binder does not have a significant effect on the thermal conductivity of the material. Composites have a coefficient of thermal conductivity required for thermal-insulation materials. 10.18720/MCE.83.13 thermal-insulation boards durability static bend thermal conductivity coefficient water absorption swelling plant waste ureaformaldehyde binder hardener extent of hardening https://engstroy.spbstu.ru/article/2018.83.13/ 13.pdf

RAR RUS 148-164 Russian Scientific Research Institute of Land Improvement Problems Kosichenko Yuri kosichenko-11@mail.ru Russian Scientific Research Institute of Land Improvement Problems Baev Oleg Oleg-Baev1@yandex.ru Water permeability of the polymer screen with a system of slits of hydraulic structures 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 free filtration through a system of screen slits (the isolated standard fragment with a single defect), characterized by a pressure movement of the filtration flow in the protective layer and pressure/pressure-free movement at the bottom of the screen, taking into account the mutual influence of the slits on each other. We obtained the calculated dependences for the determination of the specific filtration flow through the screen slit, as well as the total flow through the system of slits and the averaged screen filtration factor, the results of the calculations are compared to the known formulas for the defect system. For practical use, a table of averaged screen filtration factors and a graph of the change in the reduced flow rate through the screen, considering and not considering the influence of the underlying base are made. 10.18720/MCE.83.14 water permeability polymer screen filtration theory conformal mapping velocity hodograph irrigation https://engstroy.spbstu.ru/article/2018.83.14/ 14.pdf

RAR RUS 165-174 6602647191 GORPROJECT Travush Vladimir travush@mail.ru

3rd Floor, 5, Bldg. 5A Nizhnyi Susal'nyi lane, 105064, Moscow, Russia

JSC Research Center of Construction Krylov Sergey krylov_s_b@mail.ru JSC Research Center of Construction Konin Denis konden@inbox.ru JSC Research Center of Construction Krylov Alexey kryl07@mail.ru Ultimate state of the support zone of reinforced concrete beams A brief review of actual methods of calculation of the shear forces is performed; the calculated dependences are analyzed and their estimation is given. The shortcomings of the methods are noted, the main one is the empirical approach to the solution of the problem. The features of destruction of reinforced concrete elements along an inclined section are considered; the mechanism of destruction, on which the actual normative documents are based, is analyzed. A method of design of reinforced concrete elements under the action of shear forces is proposed. The method is developed on the basis of analysis of the stress-strain state of the support zone of a reinforced concrete beam of rectangular cross-section. In the design work, two stages are distinguished. This made it possible to avoid empirical coefficients in the equations. A numerical model was created. Stress distribution in the beam was obtained and analyzed. Conclusions about the actual stress distribution in the compressed zone of concrete above the top of the inclined crack and the actual compressive strength of concrete are made. The proposed design method made it possible to describe the process of destruction of the inclined section in strict accordance with the experimental data. The proposed approach allows to obtain accurate results not only for reinforced concrete elements of simple cross-section (rectangular, T-section), but also for other shapes of sections of a more complex configuration. 10.18720/MCE.83.15 concrete reinforced concrete reinforcement inclined cross-section shear force strength numerical simulation https://engstroy.spbstu.ru/article/2018.83.15/ 15.pdf

RAR RUS 175-185 57191530761 0000-0002-4765-5819 Moscow State University of Civil Engineering (National Research University) Alekseytsev Anatoly aalexw@mail.ru

Moscow, Russia

Technical University in Košice Al Ali Mohamad mohamad.alali@tuke.sk Optimization of hybrid I-beams using modified particle swarm method An approach for the optimization of hybrid welded I-beams based on the modification of the particle swarm method is proposed. A solution search is performed on discrete sets of variable parameters, which are taken as the size of sheets of rolled steel and steel grades. Depending on the values of the variables, a design of the support and ordinary stiffeners and their location along the length of the beam is performed. When varying the thickness of the sheets, the change in the design resistance is taken into account. As a mathematical model for calculating the stress-strain state, analytical expressions are used. To save the best solutions, the method of copying particles and their storage strategy in the database are used. This database is generated in accordance with the elitist principle, known in the evolutionary modeling theory. This makes it possible to obtain a high-performance optimization algorithm for structures of this type. The verification of the solution is performed using the finite element analysis. 10.18720/MCE.83.16 particle swarm optimization I-beam hybrid beam stiffeners flange web finite element method plastic deformations local stability overall stability https://engstroy.spbstu.ru/article/2018.83.16/ 16.pdf

RAR RUS 186-197 7004452338 0000-0001-8759-6318 National University of Water Environmental Engineering Dvorkin Leonid dvorkin.leonid@gmail.com

Rivne, Ukraine

Method of calculating the optimal sand content in normal-weight concrete 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 finding the content of sand in a mixture of concrete aggregates, which ensures the lowest viscosity of the concrete mixture and prevent water separation. Using the experimental-statistical model, a method is also proposed for finding the sand content in concrete that provides the required volume of entrained air. The proposed calculation methods are confirmed experimentally. 10.18720/MCE.83.17 concrete mixture optimal sand content viscosity water demand water separation the volume of the entrained air calculation https://engstroy.spbstu.ru/article/2018.83.17/ 17.pdf

RAR RUS 198-207 7005670404 Ivanovo State Polytechnic University Fedosov Sergey fedosov-academic53@mail.ru Ivanovo State Polytechnic University Rumyantseva Varvara varrym@gmail.com Ivanovo State Polytechnic University Krasilnikov Igor korasb@mail.ru Ivanovo State Polytechnic University Konovalova Viktoriya kotprotiv@yandex.ru Ivanovo State Polytechnic University Evsyakov Artem smart47@rambler.ru Mathematical modeling of the colmatation of concrete pores during corrosion Pore colmatation plays a positive role, since the decrease in the permeability of cement concrete due to the deposition of insoluble corrosion products in the pores leads to a slowdown in corrosion processes. The mathematical model of concrete pore colmatation based on the mass transfer equations is given, which allows to estimate the depth of corrosion damage of concretes in media of various degrees of aggressiveness. The presented model describes the rate of advance of the deposition zone of corrosion products depending on the conditions of the corrosion process. Mathematical models of the kinetics and dynamics of mass transfer accompanied by a decrease in permeability during chemical corrosion of cement stone are presented. Equations are obtained for determining the rate of advancement of the colmatation zone and the thickness of the colmatant layer during concrete corrosion. The dependence of the rate of clogging of pores and capillaries and the thickness of the sediment layer on the change in mass transfer characteristics, taking into account the porosity of the bedding layer, is shown. Graphic dependences of the rate of advancement of the colmatage zone and the thickness of the layer of corrosion products are obtained at the established porosity of the layer for cases of linear and exponential changes in the mass diffusivity coefficient over time. The obtained graphic dependences show that the intensity of the colmatation process decreases, and also illustrate a significant decrease in the intensity of the process with a slight decrease in the porosity of the sediment layer. 10.18720/MCE.83.18 colmatation colmatation of pores corrosion of concrete mathematical modeling colmatation model https://engstroy.spbstu.ru/article/2018.83.18/ 18.pdf

RAR RUS 208-221 7801674259 JSC “B.E. Vedeneev VNIIG” Shtilman Vladimir ShtilmanVB@vniig.ru JSC “B.E. Vedeneev VNIIG” Pogrebnyak Boris PogrebnyakBN@vniig.ru JSC “B.E. Vedeneev VNIIG” Arseniev Pavel ArsenjevPA@vniig.ru JSC “B.E. Vedeneev VNIIG” Shevchenko Yurii ShevchenkoYuV@gmail.com JSC "ATOMPROEKT" Kukhtevich Vladimir VOKukhtevich@atomproekt.com JSC "ATOMPROEKT" Kurchevsky Aleksey AIKurchevsky@atomproekt.com JSC «ATOMPROEKT» Matyushev Leonid LAMatyushev@atomproekt.com

St. Petersburg, Russia

Experimental justification of strainer meshes of NPP sump Processes of filter meshes clogging of emergency core cooling system sump intended for cleaning water incoming in recirculation system from sump are studied. Test rig for study of hydraulic characteristics of filter elements, which is a closed circulation loop are described. Basic principles of modeling of coolant recirculation through a filter element, occurring in event of an emergency depressurization of primary circuit, and experimental research methods are presented. Dependences of pressure drop on meshes on flow rate and amount of debris for several types of meshes on ordinary and borated water are obtained and analyzed. It is shown that the use of borated water leads to an increase in both time to reach steady state and pressure loss on meshes. Constructive measures to reduce pressure losses are proposed. 10.18720/MCE.83.19 nuclear power plant (NPP) hydraulic studies debris head loss flow rate insulation filter element https://engstroy.spbstu.ru/article/2018.83.19/ 19.pdf

RAR RUS 222-234 Peter the Great Saint Petersburg Polytechnic University Sabri Mohanad Muaya mohanad.m.sabri@gmail.com

Polytechnicheskay, 29

6507787139 OOO “PI Georekonstruktsiya” Shashkin Konstantin cshashkin@yandex.ru Improvement of the soil deformation modulus using an expandable polyurethane resin Different methods are used in the field for foundations remediation and improvement of the soil properties, but every method has its advantages and limitations. Moreover, not all the existing methods are able to stabilize the soil and elevate the foundations effectively, regulating the process depending on the desired results. The settlements of the foundations of the buildings and structures lead to negative consequences and controlling the settlements is complex itself essentially in the type of soils which contains organic materials or acids where the treated materials used might react with the soil components. The soil injection technology using an expandable polyurethane resin is an innovative technique that leads to the stabilization of the soil beside lifting and remediating of the foundations. Therefore, a full-scale experiment has been implemented in-situ to investigate the effect of injecting an expandable polyurethane resin on different soil properties besides lifting a concrete foundation. The paper demonstrates the results of an experiment which has been conducted to improve the soil's modulus of deformation, lifting of a concrete foundation, settlement compensation and increase the bearing capacity of the investigated soil after the injection of an expandable polyurethane resin consists of two components. The deformation modulus (E) of the investigated soil before and after the injection of the resin at different depths are achieved and incorporated. Also, comparisons of the load-settlement graphs at different soil depths before and after the injection of the resin are presented and analyzed. The in-situ injection process and the propagation of the resin in the soil massive are obtained and described in this paper. 10.18720/MCE.83.20 soil injection technology soil modulus of deformation soil stiffness foundation lifting soil consolidation soil improvement foundations settlement soil bearing capacity polyurethane resin https://engstroy.spbstu.ru/article/2018.83.20/ 20.pdf