75504 2712-8172 Magazine of Civil Engineering 5 81 2018 1-211
RAR RUS 3-14 Fire Academy of Emercom of Russia Polishchuk Evgeniy epyur@ya.ru Fire Academy of Emercom of Russia Sivenkov Andrey sivenkov01@mail.ru Fire Academy of Emercom of Russia Kenzhehan Samat kenzhehan85@mail.ru Heating and charring of timber constructions with thin-layer fire protection The results of fire tests of constructions (beams) with fire retardant film coating in oneside fire effect under standard temperature fire regime are shown in this article. Intensity dynamics of samples heating and their charring process in thickness and along the perimeter were chosen as the key indicators. It is shown that the use of thin-layer non-swelling fire retardant coatings does not influence the intensity dynamics, in case of high-temperature exposure generates from the side of the bottom edge, however, but is able to localize the burning action effectively, thereby producing a positive impact on the level of fire hazard and fire resistance of building constructions. The directions of possible development of methodological approach to the calculation and analytical assessment of fire retardant indicators and classes of fire hazard of timber constructions with non-construction fire protection have been determined. 10.18720/MCE.81.1 timber construction; fire protection; charring; wood; fire resistance; prediction method https://engstroy.spbstu.ru/article/2018.81.1/ 01.pdf
RAR RUS 15-24 Peter the Great Saint Petersburg Polytechnic University Bolshakov Nikolai nikolaybolshakov7@gmail.com
Polytechnicheskay, 29
 Peter the Great St. Petersburg Polytechnic University Badenko Vladimir vbadenko@gmail.com
St. Petersburg, Russia
 Politecnico di Milano Celani Alberto alberto.celani@polimi.it
Milan, Italy
 Site-selection on the basis of territorial analysis methods The object of research is the site-selection process for the rental housing construction. This form of real estate is becoming more widespread in the west, while in Russia it’s development is currently on initial stage. The article proposes the site-selection solution on the basis of existing methods of territorial analysis, calculation of employment shares, location quotients, Hirschmann-Herfindahl index and Kano model application, as well as application examples of the obtained databases in the conditions of a narrowly formulated problem. The research results are the mechanisms for solving three types of problems depending on the nature of the initial data according to correspondence between the properties of the object under construction and the urban territories. 10.18720/MCE.81.2 site-selection; territorial analysis; urban planning; regional economics; decisionmaking; location quotient; rental house https://engstroy.spbstu.ru/article/2018.81.2/ 02.pdf
RAR RUS 25-31 Peter the Great Saint Petersburg Polytechnic University Petrochenko Marina mpetroch@mail.ru
Polytechnicheskay, 29
 Peter the Great Saint Petersburg Polytechnic University Velichkin Viktor V.Velichkin2011@yandex.ru
Polytechnicheskay, 29
 St. Petersburg State University of Architecture and Civil Engineering Kazakov Yuryi kazakov@spbgasu.ru Peter the Great Saint Petersburg Polytechnic University Zavodnova Yevgeniya yavtushenko_89@mail.ru
Polytechnicheskay, 29
 Reliability assessment of the construction schedule by the critical chain method Implementation of the construction projects is associated with significant current material, technical and financial costs. They increase significantly in case of the breaking deadlines the large stages of projects and putting buildings into operation. The main aim of the current research is development the new approach for reliability model of the construction schedule for increasing reliability of the calendar planning regarding the meeting the construction projects on time. The following task were solved: the model of technical, labor and time reserves was developed; the algorithm of effective operational management system for the entire construction production process was offered. The probability of task completion was assessed by the E.M. Goldratt method, the probability function, based on the beta distribution was used. Initiating a shorter work execution period as a more stringent control action leads to an increase in the reliability of the construction program in the established settlement (contract) time from 50% probability to the normative 90% probability. Probabilistic approach allows to assess the achieved effect of applying the methodology of EM. Goldratt for the streamlined construction and to take a measured deadline for the execution of tasks in the development of the construction project. 10.18720/MCE.81.3 project management; schedule control; baseline term; critical path; Goldratt’s method; project buffer; construction project; critical chain; theory of constraints; construction management https://engstroy.spbstu.ru/article/2018.81.3/ 03.pdf
RAR RUS 32-42 57191530761 0000-0002-4765-5819 Moscow State University of Civil Engineering (National Research University) Alekseytsev Anatoly aalexw@mail.ru
Moscow, Russia
 Bryansk State University of Engineering and Technology Akhremenko Sergey aalexw@mail.ru
Bryansk, Russia
 Evolutionary optimization of prestressed steel frames A method for the optimal synthesis of prestressed steel frame structures is developed. The search for a solution is being carried out by applying discrete sets of variable parameters, including cross-sections of structural rods and cross-sections of prestressing tie-rods. It is possible to vary the location of the prestressing system. To optimize the cost of the objects under consideration, an improved meth-od of evolutionary simulation has been used, including a combined scheme for constraints set and an unusual scheme for the formation of populations. Strength and stiffness considerations for a number of objects within a population are not strict, and for variants with breached constraints, a penalty function has been applied. In forming the current population used to modify the individuals, multipoint genetic operators, random generation, and a strategy of elitism have been applied. To vary the location of the prestressing system and take into account the multivariance of loads, parallel evolving populations have been introduced, between which a limited exchange of individuals is allowed. Examples of optimization of prestressed frames with girders and trusses were considered. 10.18720/MCE.81.4 prestressed frames; evolutionary optimization; a mixed account of constraints; weakly interacting populations; adaptive genetic operators https://engstroy.spbstu.ru/article/2018.81.4/ 04.pdf
RAR RUS 43-51 Peter the Great Saint Petersburg Polytechnic University Zalata Ekaterina ekaterinazalata@gmail.com
Polytechnicheskay, 29
 Peter the Great Saint Petersburg Polytechnic University Shavrov Yurii Sharohka@mail.ru
Polytechnicheskay, 29
 Peter the Great St. Petersburg Polytechnic University Strelets Kseniya kstrelets@mail.ru
29 Politechnicheskaya St., St. Petersburg, 195251, Russia
 St. Petersburg State University Emelyanova Maria margar9@mail.ru Productivity of microalgae as biofuel for bioadaptive systems of facades 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 work is to study the productivity of microalgae Chlorella of CALU 157 strain at low temperatures and low illumination, as well as to calculate the amount of biofuel that can be produced under such climatic conditions. In the first stage of the experiment the algae cultivation was studied at different illumination values – 3500 lx, 1750 lx and 930 lx. In the second stage of the experiment cultivation of algae at different temperatures was studied: +2 °C, +10 °C, +19 °C and +25 °C. Total number of cells in the suspension was determined using the method of direct cell counting in Goryaev chamber. As a result of the experiment microalgae productivity data were obtained at different illumination and temperature. It was found that at a temperature of 2 °C and 10 °C, an almost stable state of algae was observed, the concentration increased very slowly, however the culture did not die. Also the calculation of the amount of energy and biogas, which can be obtained from the biomass of microalgae under the growing conditions of 3500 lx and 23 °C was also made. 10.18720/MCE.81.5 energy efficient façade; microalgae; biofuel; biogas https://engstroy.spbstu.ru/article/2018.81.5/ 05.pdf
RAR RUS 52-63 V.I. Vernadsky Crimean Federal University Alekseenko Vasiliy avn108@mail.ru 57194105536 https://orcid.org/0000-0003-4486-5869 V.I. Vernadsky Crimean Federal University Zhilenko Oksana o.b.zhilenko@mail.ru Technical University in Košice Al Ali Mohamad mohamad.alali@tuke.sk Bearing capacity of pasted anchors in the masonry walls of natural limestone The joint work of pasted steel anchors and wall masonry elements from natural limestone is discussed in the article. The aim of the scientific work is the development of a technique for calculating the load-bearing capacity of anchors in masonry walls from natural limestone and the development of nomograms for the rapid evaluation of the bearing capacity of anchors. The state of the problem of the work of pasted anchors in various materials was studied. It is established that the known methods for calculating the strength of pasted steel anchors do not take into account the joint work of the natural limestone and pasted steel anchor. Previous studies have focused on the study of anchor joints in concrete, and the work of the pasted joint in the masonry walls of natural limestone has not been investigated. In the present work, for the experimental study of the work of pasted steel anchors in the masonry of walls made of natural limestone, the following materials were accepted: natural limestone, periodic profile reinforcement and anchor mixture. General methods of experimental and theoretical research: analysis, synthesis, deduction, induction, analogy. To solve the set tasks, in the experimental part, the strength of the adhesive joint for pulling in stone elements after the strength of the anchor mixture was established, when fitting the fixture ø 12 mm А 500С into it. Experimental samples, tested to determine the strength of the adhesive joint, were destroyed by breaking the stone. This fact confirms the higher strength of the adhesive bond than the stone element. The results of the physical experiment performed by the authors for determining the parameters of the joint work of the pasted steel anchor and the stone elements from natural limestone are presented in article. It has been experimentally established that 0.4 mm is the criterion for the limiting displacement of anchors, in which splitting of stones from the effect of transverse tensile stresses caused by pulling out pasted steel anchors is not allowed. The estimated evaluation of the joint work of pasted steel anchors and wall masonry elements from natural limestone was proposed. 10.18720/MCE.81.6 natural limestone; pasted steel anchor; anchor mixture; physical experiment; calculation; Civil Engineering; Construction Industry; Buildings https://engstroy.spbstu.ru/article/2018.81.6/ 06.pdf
RAR RUS 64-72 Petersburg State Transport University Nesterova Olga neona975@yandex.ru Petersburg State Transport University Uzdin Alexander uzdin@mail.ru St.Petersburg State University of Film and Television Fedorova Maria mgfed@mail.ru Method for calculating strongly damped systems with non-proportional damping The calculation of systems under seismic excitations is performed both dynamically by time integration and quasistatically under inertial seismic loads using linear response-spectra method (RSM). Dynamic timing calculation can be performed either using direct integration of the initial system of motion equations, or by using the spectral decomposition of motion equations by shape modes. RSM is completely based on spectral decomposition. However, the spectral decomposition was worked out only for systems with proportional damping, when the eigenvectors of the undamped and damped systems coincide. With regard to RSM, even for proportional damping, the existing Guide Lines do not allow to take into account the actual damping in the system. There are proposals for the explicit calculation of damping within the framework of the RSM for proportional damping in literature. Their results can be used both for constructing RSM and for integrating motion equations with arbitrary damping using the spectral decomposition of the motion equations. But so far the mentioned mathematical results have not been connected with calculating structures. The authors propose a variant of the RSM for calculating highly damped systems under earthquake impact. To this aim, complex eigenvectors and eigenvalues of the motion equation system were obtained, and this system was reduced to a tridiagonal form. As a result, the assumed equation system of the order equal to N was decomposed into N pairs of independent real equations. The base oscillation accelerogram and its derivative present the input in the right part of the motion equations. In this way two matrices of seismic forces are generally obtained. To sum up these forces, the shape mode correlation coefficients were analyzed. An example of mass damper calculation is given in the paper. For 4-6-story buildings constructed in ordinary conditions the proposed variant of the RSM leads to the same data that existing Guide Lines. But the proposed variant of RSM makes it possible to calculate systems with heterogeneous damping including seismic isolated systems, mass dampers and systems with soil-structure interaction which is impossible to do on the base of the existing Guide Lines. 10.18720/MCE.81.7 earthquake engineering; calculation; strongly damped system https://engstroy.spbstu.ru/article/2018.81.7/ 07.pdf
RAR RUS 73-78 6602647191 GORPROJECT Travush Vladimir travush@mail.ru
3rd Floor, 5, Bldg. 5A Nizhnyi Susal'nyi lane, 105064, Moscow, Russia
 57196437054 0000-0002-5392-9150 National Research Moscow State Civil Engineering University Fedorova Nataliya fenavit@mail.ru
Moscow, Russia
 Survivability of structural systems of buildings with special effects The technique of calculation analysis of survivability of reinforced concrete statically indeterminate beams and rod structural systems of buildings and structures under emergency influences is given. The statement of the problem of the computational analysis of the survivability of such constructive systems and the algorithm for determining the survivability parameter under special influences in the form of a sudden shutdown of one of the constructions is expounded. The criteria of the bearing capacity for a particular limiting state for the considered constructive systems arising under such influences are proposed, the excess of which can cause a progressive destruction of the constructive system. An example of a computational analysis of the survivability of a statically indeterminate reinforced concrete continuous beam in comparison of the theoretical results obtained with the results of its experimental studies is considered. However, the problem can be used for determining the parameter of the survivability of buildings and structures for the examined impacts. 10.18720/MCE.81.8 survivability of structures; survivability parameter; structural system; static and dynamic diagram; added dynamic loading https://engstroy.spbstu.ru/article/2018.81.8/ 08.pdf
RAR RUS 81-92 National Research Moscow State Civil Engineering University Akhmetov Vadim vadim.akhmetov@gmail.com Belarusian State University Konon Pavel kononp@tut.by Aerodynamics of building structures for flue gas removal Natural fuel burning in modern heat power plants with flue gas formation is accompanied with harmful environmental impact and potential opportunity of acid fallout. This can lead to local or even global catastrophe under adverse circumstances. High-rise structures combining a smokestack and a cooling tower are used for ecological natural fuel burning. The most important problem of these structures design is to study gas-dynamic behavior of flue gas mixing with warm ambient air flow during its movement along exhaust duct. Mathematical model and efficient numerical technique for problem solution have been developed in this work. The flowfields and the temperature and concentration distributions are calculated for various inlet conditions. Swirl flow ratio influence on flow nature has been studied. Obtained solutions have been compared with available experimental data and numerical researches. Calculation results can be used in search of optimum building structures. 10.18720/MCE.81.9 high-rise buildings; power engineering; cooling tower; smokestack; gas dynamics; numerical method https://engstroy.spbstu.ru/article/2018.81.9/ 09.pdf
RAR RUS 93-101 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
 University of Calabria Rossi Cesare cesare.oliviero@unical.it Kazakhstan Highway Research Institute Ashimova Saltanat salta_32@mail.ru Composition and rheological characteristics of bitumen in short-term and long-term aging 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 long-term aging - in the pressure aging vessel (PAV) under the standard of ASTM D 6521-08. Mechanical characteristics of the bitumen are complex shear modulus G* and phase angle δ at the mean and high temperatures (from 4 °С to 76 °С) have been measured by dynamic shear rheometer (DSR) under the standard of AASHTO T 315-08. Bitumen stiffness S at low temperatures (from -24 °С to -36 °С) has been measured by bending beam rheometer (BBR) under the standard of AASHTO T 313-08. It has been determined that during short-term aging the content of oils in the bitumen has been decreased for 1.5 %, and the content of asphaltenes has been increased for 2 %. After the long-term aging, performed after the short-term aging, the content of oils in the bitumen has been decreased for 7 %, and the content of asphaltenes has been increased for 6.3 %. The content of resins in the bitumen remains practically constant at both types of aging. At the mean and high temperatures the short-term and long-term aging increase the complex shear modulus up to 2 and 7 200 times respectively and decrease the phase angle at average for 4-6° and 8-10° respectively. At low temperatures the short-term aging and long-term aging increase the bitumen stiffness in 1.5 and 2.5 times respectively. 10.18720/MCE.81.10 blown bitumen; short-term aging; long-term aging; dynamic shear rheometer; bending beam rheometer; complex shear modulus; phase angle; stiffness https://engstroy.spbstu.ru/article/2018.81.10/ 10.pdf
RAR RUS 102-115 Artiukh Viktor Peter the Great Saint Petersburg Polytechnic University Galikhanova Elina elinlvs.g@gmail.com
St. Petersburg, Russia
 LLC “Saint-Petersburg Electrotechnical Company” Mazur Vladlen mazur@spbec.com Pryazovskyi State Technical University Kargin Sergey vbudar1973@gmail.com Energy intensity of parts made from polyurethane elastomers Laboratory testing with determination of strength and energy characteristics of materials for elastic elements of shock absorbers helped to establish that polyurethane elastomers, having the highest values of specific energy consumption and a wide range of alternating dissipation and rigidity characteristics were the best materials. It will allow to create a series of efficient shock absorbers for different elements and units of building constructions. As the result of the analysis performed of different types of steel springs a coefficient of spring’s quality in volume was obtained, as well as coefficient of spring’s quality in weight, coefficients of shape for cylindrical, crew-type and plate springs. These coefficients can help to arrive at the conclusion, regarding the appropriateness of this spring for a particular elements and units of building constructions. 10.18720/MCE.81.11 energy consumption; polyurethane; elastomer; shock absorber; elastic element https://engstroy.spbstu.ru/article/2018.81.11/ 11.pdf
RAR RUS 116-124 Lobachevsky State University of Nizhny Novgorod Anikina Nadezhda undinaf@gmail.com Lobachevsky State University of Nizhny Novgorod Smirnova Olga protectfun@mail.ru Lobachevsky State University of Nizhny Novgorod Smirnov Vasiliy protectfun@mail.ru Lobachevsky State University of Nizhni Novgorod Zaharova Elena zaharova_elena_aleksandrovna@mail.ru Protection of construction materials based on acrylates from biodeterioration The article is dedicated to the funginertness of different construction materials based on acrylates: emulsions Lakroten E-21, Lakroten E-31, Latacryl ZM-1, and Latacryl AF, as well as metacrylate, metacrylate copolymer with metacrylic acid, and n-chlorophenylmetacrylate acrylic glasses. All studied materials, except the Latacryl ZM-1 and copolymer acrylic glasses, demonstrated susceptibility to biodeterioration by microfungi. Multi-compound acrylic compositions appeared to exhibit the emergence, i.e. their funginertness cannot be predicted based on stability of their individual components. Fungal exooxidoreductases (catalase, peroxidase) were defined to contribute into the biodegradation processes in construction materials based on acrylates by micromycetes. The biocides Nuosept 78 and Rosima 243 demonstrated the ability to suppress exo-catalase and exo-peroxidase activity (exo-catalase and exoperoxidase participate in the biodeterioration of the studied materials) in the fungus Aspergillus terreus; thus, they can be recommended for use as means of bioprotection. The non-fungi-resistant acrylic materials were protected from biodeterioration in a targeted and scientifically-grounded way by the introduction of the abovementioned biocidal additives into their compositions. The bioprotection is based on biochemical aspects of biodestructive microfungal activity. 10.18720/MCE.81.12 construction materials based on acrylates; funginertness; microfungi; enzyme activity; biodeterioration of buildings and construction; fungicidal additives; protection from biodeterioration https://engstroy.spbstu.ru/article/2018.81.12/ 12.pdf
RAR RUS 125-134 Tomsk State University of Architecture and Building Shepelenko Tatiana shepta72@mail.ru Tomsk State University of Architecture and Building Gorlenko Nicholas Gorlen52@mail.ru Tomsk State University of Architecture and Building Zubkova Olga zubkova0506@mail.ru Structurization processes of cement composites modified with electrolytic additives There has been research on the impact of AlCl3 and FeCl3 solutions on kinetics of cement hardening. The research was carried out in two comparative versions, one of which had the saline solutions introduced into cement as gauge liquid (“water–1% electrolytic solution”), the other had them as additives, synthesized in suspensions “cement – (water–1% electrolytic solution)”. It has been stated that the use of AlCl3 and FeCl3 solutions as gauge liquids leads to reduction of compression resistance values of modified cement rocks. The value of 28-day hardness, compared to plain cement, is reduced by 18 % in case of cement gauging with AlCl3 solution, and by 27% in case of binder gauging with FeCl3 solution. On the contrary, the composites, produced by means of introducing the additives, synthesized within suspensions, into cement paste, have shown a significant boost in 28-day hardness compared to plain sample – by 30 and 23 % accordingly. The analysis of the result studies of the additives by means of XPA and IR-spectral analysis has shown that within the structurization of additives the interrelated changes take place, due to the rapid decrease of portlandite amount and carbonization. The authors suppose the acceleration of setting and the higher strength of cement composite with the introduced additive, synthesized by means of cement exposure to 1 % AlCl3 solution, to take place due to synergic influence of a number of factors: intensive growth of ettringite crystal seeds and badly crystallized phases of hydrated calcium silicates of tobermorite-like structure; reduction of Ca(OH)2 in the hard phase of a cement rock; and carbonization effect, which includes the formation of crystal phase for Ca8Al12Fe2C12(CO3)∙(OH)2∙22H2O. The improvement of density properties of a cement composite after introducing the additive, synthesized by means of cement exposure to 1 % FeCl3 solution, is probably facilitated by gauging of Ca(OH)2, or may be explained by “working” CaCO3 and ettringite microcrystals, catalyzing the intergrowth of composite skeletal frame, or by “working” gelatinous hydrated calcium ferrites and silicates, characterized by a high surface area, which facilitate and boost interphase contacts, increasing the density of cement systems. 10.18720/MCE.81.13 cement; electrolytic solutions; aluminium and ferric chloride solutions; additives; strength https://engstroy.spbstu.ru/article/2018.81.13/ 13.pdf
RAR RUS 135-148 6506150284 0000-0003-1139-3164 Moscow State University of Civil Engineering (National Research University) Sainov Mikhail mp_sainov@mail.ru
Moscow, Russia
 National Research Moscow State Civil Engineering University Soroka Vladislav vastion08@yandex.ru Ultra-high rockfill dam with combination of the reinforced concrete face and clay-cement diaphragm The article deals with design validation of a new type of an embankment dam structural design, i.e. rockfill dam with combination of two types of non-soil seepage-control elements – a reinforced concrete face (in the dam upper part) and a clay-cement diaphragm made of bored piles (in the dam lower part). The dam of the considered design has a number of advantages over classical structural design of concrete faced rockfill dam (CFRD). First of all, conjugation of the seepage-control element with rock foundation does not require arrangement of a pit. Secondly, repairs of the dam lower part may be carried out by arrangement of a grout curtain. But the most important advantage of this design is more favorable conditions of the reinforced concrete operation, i.e. the face is subject to not tensile, but compressive longitudinal force. This decreases the risk of cracking in the face. Design validation of this structural design was conducted on the example of a 235 m high dam. Numerical modeling of the dam stress-strain state (SSS) was performed with consideration of construction and loading sequence, as well as with consideration non-linearity of rockfill deformation. Impact of four main factors on the dam SSS was studied: rockfill deformation, clay-cement deformation, diaphragm height and reinforced concrete thickness. Several alternatives of the dam design parameters were considered. Design of the numerical experiment was conducted by the method of factor analysis. This permitted revealing the impact of the considered factors on the dam SSS, as well as solving the problem on optimization of the dam structural solution. It was revealed that for providing the necessary level of the dam design safety the rockfill deformation modulus should be at least 250 MPa, and the diaphragm should be made of plastic clay-cement concrete. More favorable turned to be the case when the diaphragm height is 20 m but not 35 m. 10.18720/MCE.81.14 rockfill dam; reinforced concrete face; cutoff wall slurry trench; stress-strain state; numerical modeling https://engstroy.spbstu.ru/article/2018.81.14/ 14.pdf
RAR RUS 149-159 54938263800 St. Petersburg State University of Architecture and Civil Engineering Lukashevich Anatoliy a.luk@bk.ru
2-nd Krasnoarmeiskaya St. 4, 190005 St. Petersburg, Russia
 Computational modelling of stiffness and strength properties of the contact seam 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 contact model and the method of step-by-step analysis, a numerical algorithm for solving the contact problem has been developed taking into account the deformation and strength properties of the seam material. This approach allows in one step-by-step cycle to perform simultaneous account of the initial strength of the contact seam, as well as the conditions of unilateral deformable constraints and friction-sliding of its surfaces in areas where the strength of the contact seam is broken. The use of frame-rod contact elements allows the physical nonlinearity of the contact layer to reduce to the internal nonlinearity of only the system of contact elements, while the nonlinear properties of the seam are set by means of the nonlinear characteristics of the individual rods of contact elements. Iterative refinement of the nonlinear solution for the current level of loading is performed by the method of compensating loads. With the help of the proposed approach, the numerical solution of the problem of contact of the structure with the base under different conditions of the contact seam has been obtained and analyzed. 10.18720/MCE.81.15 contact problem; unilateral constraints; step-by-step analysis; contact seam; nonlinear deformability; initial strength https://engstroy.spbstu.ru/article/2018.81.15/ 15.pdf
RAR RUS 160-173 55534147800 0000-0001-5290-3429 Southwest State University Kolchunov Vladimir sjs28@mail.ru 57202804437 Southwest State University Dem'yanov Alexey speccompany@gmail.com The modeling method of discrete cracks in reinforced concrete under the torsion with bending The most famous of computer systems for the design of reinforced concrete structures in the world are taken into account only regular dispersed cracks. Completely different criteria should be used when analyzing the appearance and development of discrete cracks in reinforced concrete, the modeling methodology of which has not been developed to date. Therefore, the article provides working prerequisites, a methodology for simulating discrete cracks and calculating their rigidity. Several levels of cracking are considered. The development of spatial cracks is carried out on special bilinear surfaces. Then they fit in the approximating spatial finite elements that "expand", modeling a spatial crack, the opening of which is given in the form of a deformation effect with allowance for the discontinuity effect. When solving the inverse problem of determining the crack opening width, the deformation effect is not specified, and only the presence of a gap of the minimum possible width is modeled by means of an embossing; its opening, with appropriate loading, determines the width of the crack opening as the divergence of the shores of this gap. It is considered another variant of simulation of discrete spatial cracks in the article, in case of their implicit manifestation. Here pairs of finite elements adjacent to such a crack are distinguished from opposite sides. It is a special two-element design console model. These pairs are considered in two states: before their "expand" and after their "expand" taking into account the deformation effect and the discontinuity effect of concrete. It is introduced the classification of basic spatial cracks in spatial reinforced concrete composite constructions, cracks that develop to zones or from zones of geometric concentration; cracks that develop to zones or from zones of force and strain concentration of loading; cracks that develop in zones of inter-medial strain concentration. Their scheme is supplemented and based on these basic cracks by applying adjacent cracks, which are sought using the deformation criterion for their formation and the method of finding the extremum of a function of many variables using the Lagrange multipliers. 10.18720/MCE.81.16 reinforced concrete plane-stressed composite constructions; spatial cracks; torsion with bending; double-console scheme; distance between cracks; width of crack opening https://engstroy.spbstu.ru/article/2018.81.16/ 16.pdf
RAR RUS 174-182 H-9967-2013 16412815600 0000-0002-8588-3871 National Research University "Moscow Power Engineering Institute" Kirsanov Mikhail mpei2004@yandex.ru
14, Krasnokazarmennaya, 111250 Moscow, Russia
 Installation diagram of the lattice truss with an arbitrary number of panels Hereby the diagram of a flat statically determinate regular lattice truss with the parallel chords is proposed. The task is to obtain an analytical dependence of the truss deflection and forces in the most tension and compressed bars on the number of panels. In order to solve the problem, the Maple computing mathematical system is used. We have considered the case when the lower truss chord is subject to a uniform load. The forces are determined by the Method of Joint. The Maxwell-Mohr formula is used to determine the deflection. The solution obtained for a set of cases with different successively increasing numbers of panels is generalized to a random number of panels by method of induction. The special operators of the Maple system are used to prepare homogeneous linear recurrence relations that are satisfied with the sequences of coefficients in the required formula. It is shown that for the number of panels in the half-span that are divisible to three, the determinant of the equilibrium equation system is becoming zero. The truss is becoming kinematically changeable that is confirmed by the corresponding diagram of possible joint velocity. The algorithm for the truss installation diagram is described, where the cross bars are in different planes and are connected in the nodes so that the truss elements are not subjected to buckling. The solution of this problem is related to the correct edge coloring of graphs and hypergraphs. 10.18720/MCE.81.17 truss; deflection; induction; Maple; exact formula; edge coloring; hypergraph https://engstroy.spbstu.ru/article/2018.81.17/ 17.pdf
RAR RUS 183-192 M-6585-2013 6508103761 0000-0002-1196-8004 Peter the Great Saint Petersburg Polytechnic University Vatin Nikolai vatin@mail.ru
Polytechnicheskay, 29
 Peter the Great Saint Petersburg Polytechnic University Pestryakov Igor iscvisota@mail.ru
Polytechnicheskay, 29
 Peter the Great Saint Petersburg Polytechnic University Sultanov Shukhrat sultanov.sht@edu.spbstu.ru
Polytechnicheskay, 29
 Peter the Great Saint Petersburg Polytechnic University Ogidan Olamipe Timothy ogidano@gmail.com
Polytechnicheskay, 29
 Peter the Great Saint Petersburg Polytechnic University Yarunicheva Yuliya julija.jarunicheva@gmail.com
Polytechnicheskay, 29
 Peter the Great Saint Petersburg Polytechnic University Kiryushina Anastasia nastyakik97@mail.ru
Polytechnicheskay, 29
 Water vapour by diffusion and mineral wool thermal insulation materials This article is aimed at determining the absorption of moisture by diffusion of mineral wool and polyisocyanurate over a long-term period. The task of increasing the thermal insulation properties of enclosing structures is most relevant for the erection of new buildings or structures, as well as for the repair of existing. The method models operating conditions in which thermal insulation product absorb moisture from both sides at high relative humidity of air (100%) and pressure difference of water vapour over a longterm period. The moisture absorption by diffusion of mineral wool and polyisocyanurate were obtained after 28 days of exposure to temperature and pressure drop of water vapor. Significant changes in moisture content of mineral wool were observed. From the results obtained, it can be concluded that polyisocyanurate has a lesser absorption property of water vapor, which is an important attribute in its operation. 10.18720/MCE.81.18 insulation; water vapour diffusion; humidity; polyisocyanurate; mineral wool; moisture content; water absorption; relative humidity; energy efficiency https://engstroy.spbstu.ru/article/2018.81.18/ 18.pdf
RAR RUS 193-201 Vladimir State University named after Alexander and Nikolay Stoletovs Koshcheev Artyom kibole@mail.ru Vladimir State University named after Alexander and Nikolay Stoletovs Roshchina Svetlana rsi3@mail.ru Vladimir State University named after Alexander and Nikolay Stoletovs Lukin Mikhail lukin_mihail_22@mail.ru Vladimir State University named after Alexander and Nikolay Stoletovs Lisyatnikov Mikhail mlisyatnikov@mail.ru Wooden beams with reinforcement along a curvilinear trajectory The article is devoted to the investigation of a new type of reinforcement of wooden beams for floors and coatings with using steel cable reinforcement located in a solid wood along a curved S-shaped trajectory. The basic principles of a new type of reinforcement are set up. The schemes of various reinforcement paths are given. Mathematical models of studied structures are formed. The stress-strain state of several beams with different variants of reinforcing paths in the working environment of the software complex SCAD, which calculates the beams studied by the finite element method, has been studied. The results of the work are presented in the form of indicators of deflections of beams and isopoles of stresses. A comparative analysis of the studied structures with non-reinforced beams and the traditional reinforcement method is carried out. Conclusions are made about the increase in the strength characteristics of the beams, in which the steel cable armature is used. The optimal trajectory path for the reinforcement groove is selected. The competitive advantages and prospects of using a new type of reinforcement are determined. 10.18720/MCE.81.19 construction materials; building construction; reinforcement of wooden beams; strength; elasticity; seismic resistance; resourcesaving https://engstroy.spbstu.ru/article/2018.81.19/ 19.pdf
RAR RUS 202-211 St. Petersburg State University of Architecture and Civil Engineering Pukhkal Viktor pva1111@rambler.ru Mottaeva Andzhela angela1309.m@yandex.ru FEM modeling of external walls made of autoclaved aerated concrete blocks The FEM-analysis of factors influencing the heat transfer properties of external walls made of autoclaved aerated concrete blocks is presented. Using the ELCUT program, the external wall temperature fields made of autoclaved aerated concrete blocks were calculated for different values of thermal conductivity for laying cement mortar and laying with adhesive. The temperature field was calculated for a junction of a top floor slab with a two-layer external wall having a facing brick layer and no air cavity. The possibility of condensation of moisture on the surface of the ceiling is established. The values of heating performance uniformity of heat productivity, reduced thermal resistance and heat fluxes for external walls are determined. The calculated values of heating performance uniformity of heat output are obtained depending on the coefficient of thermal conductivity of autoclaved aerated concrete blocks. Further development of the research will be the use of data in calculating the payback period of energy efficiency measures for buildings. 10.18720/MCE.81.20 external walls; autoclaved aerated concrete blocks; heating performance uniformity coefficient; reduced thermal resistance; modelling; FEM https://engstroy.spbstu.ru/article/2018.81.20/ 20.pdf