75504 2712-8172 Magazine of Civil Engineering 2 94 2020 1-157
RAR RUS 3-10 56200412900 https://orcid.org/0000-0002-5851-152X Nosov Magnitogorsk State Technical University Krishan Anatolii kris_al@mail.ru
Magnitogorsk, Russia
 57197845922 https://orcid.org/0000-0001-6608-8293 Nosov Magnitogorsk State Technical University Narkevich Mikhail Narkevich_MU@mail.ru
Magnitogorsk, Russia
 6505488223 https://orcid.org/0000-0003-1982-3421 Nosov Magnitogorsk State Technical University Sagadatov Azat azat0680@mail.ru
Magnitogorsk, Russia
 56258934600 https://orcid.org/0000-0002-9084-4105 National Research Moscow State Civil Engineering University Rimshin Vladimir v.rimshin@niisf.ru
Moscow, Russia
 The strength of short compressed concrete elements in a fiberglass shell Experimental studies of short axially compressed cylindric elements with various indirect concrete reinforcements – fiberglass shells, steel spirals, and the joint use of these two types of reinforcement – have been carried out. The results of the experiments performed confirm the positive effect of both the outer fiberglass shell and spiral reinforcement on the strength of such elements. The highest strength was achieved with the simultaneous use of both types of indirect reinforcement. The presence of two types of indirect reinforcement significantly increased the deformability of the compressed elements under study. The maximum recorded values of the longitudinal deformations of shortening of such samples amounted to about 1.7 %. Such a high deformability of the compressed elements will allow to use high – strength longitudinal reinforcement efficiently in them. We list the main premises and dependencies of the method of deformational calculation of the strength of compressed concrete structures with indirect reinforcements. A performed comparison of the calculation results with experimental data indicates that the proposed method is perfectly suitable for practical use. 10.18720/MCE.94.1 columns (structural) concretes elasticity fiber reinforced plastics fibers filament winding stress-strain curves structural design tubes (components) https://engstroy.spbstu.ru/article/2020.94.1/
RAR RUS 11-20 56296687300 0000-0002-2299-3096 Peter the Great Saint Petersburg Polytechnic University Rybakov Vladimir fishermanoff@mail.ru
Polytechnicheskay, 29
 Peter the Great Saint Petersburg Polytechnic University Ananeva Irina irina.ananeva94@yandex.ru
Polytechnicheskay, 29
 «Airline» Pichugin Egor pichugin_egor93@mail.ru
Moscow, Russia
 6506030356 0000-0001-6744-9249 Tampere University Garifullin Marsel marsel.garifullin@tut.fi
Kalevantie 4, FI-33100, Tampere, Finland
 Heat protective properties of enclosure structure from thin-wall profiles with foamed concrete Receiving the qualitative, energy efficient and economic building is the main tendency in the civil engineering. One of the leading places is occupied by technology of frame-panel construction with use of new non-autoclaved, monolithic foamed concrete technology producing on a building site. On the example of the real samples there were determined the heat-shielding properties of foamed concrete in a condition of setting process and after attainment of strength with a practical and theoretical methods. The results were obtained for a non-autoclaved monolithic foamed concrete wall fragment (lightweight steel concrete structure – LSCS) for the areas with and without rigid reinforcement with steel thin-wall profiles (lightweight gauge steel structure – LGSS). Influence of the thermal bypass on cold-resisting properties of enclosure structures with technology “Intech LB” is revealed. On the basis of the received results, modernization of a design for improvement of its thermotechnical characteristics is made. 10.18720/MCE.94.2 samples non-autoclaved monolithic foamed concrete rigid reinforcement steel thin-wall profiles cold-resisting properties SOVBI technology thermotechnical characteristics https://engstroy.spbstu.ru/article/2020.94.2/
RAR RUS 21-30 56297305000 https://orcid.org/0000-0001-7362-0399 Siberian State Automobile and Highway University Matveev Sergey dfsibadi@mail.ru
Omsk, Russia
 https://orcid.org/0000-0001-7632-873X The Siberian State Automobile and Highway University Martynov Evgeny asp_evg@mail.ru
Omsk, Russia
 https://orcid.org/0000-0003-2255-4613 Siberian State Automobile and Highway University Litvinov Nikolai niklitvinov_23@mail.ru
Omsk, Russia
 https://orcid.org/0000-0001-5428-6145 Siberian State Automobile and Highway University Kadisov Grigoriy kadisov@rambler.ru
Omsk, Russia
 Siberian State Automobile and Highway University Utkin Vladimir prof.utkin@mail.ru
Omsk, Russia
 The geogrid-reinforced gravel base pavement model The design model of reinforced crushed stone layer calculating as a multilayer plate on an elastic base using the technical theory of bending and the Bubnov-Galerkin method is proposed, which makes it possible to theoretically calculate and justify the effectiveness of using various types of geosynthetic materials for reinforcing pavement bases made of granular materials. The model is based on the hypothesis that the reinforced granular layer is deformed like a plate on an elastic base because of the mechanical connection with the geogrid. The calculating model is a multilayer plate consisting of an arbitrary number of solid homogeneous rigidly interconnected layers. The possibility of using this model for calculation of reinforced granular pavement base is confirmed experimentally. The results of the stamp tests showed satisfactory agreement with the results of theoretical studies. The discrepancy did not exceed 15 %. 10.18720/MCE.94.3 granular roadbed basis geogrid reinforcement stiffness deflections design model multilayered plate https://engstroy.spbstu.ru/article/2020.94.3/
RAR RUS 31-53 Ayandegan Institute of Higher Education Nejati Faezeh civilifa_nj@yahoo.com
Tonekabon, Iran
 Ayandegan Institute of Higher Education Zhian Milad miladjyane@gmail.com
Tonekabon, Iran
 Ayandegan Institute of Higher Education Safar Mashaie Fatemeh honik_ir@yahoo.com
Tonekabon, Iran
 Ayandegan Institute of Higher Education Edalatpanah Seyyed Ahmad saedalatpanah@gmail.com
Tonekabon, Iran
 Computational modeling of yielding octagonal connection for concentrically braced frames Ductility is a feature which allows a structure to undergo large plastic deformations without any strength loss. Yield dampers are energy dissipation devices which increase the ductility and control the vibration of structures by absorbing earthquake input energy. If a structure is properly designed according to the standard, if a severe earthquake occurs, it will cause serious damage to the structure. If this happens in a massive city, thousands of people are homeless and need to evacuate the debris that it seems impossible to do. Therefore, the design of systems that lead the damage to a certain part of structures is required. Incorporating an energy-dissipater element in the braces is one of the novel approaches to increase the ductility of the braces. This study aims to assess the influence of design parameters related to the energy absorption device on the seismic response of CBFs. These factors include the yield strength, initial stiffness, and strain hardening ratio. Thus a regular octagonal-shaped energy absorption device is introduced, which enters the non-linear range by steel yielding in order to dissipate the earthquake input energy and prevent other structural members from entering the plastic region. The proposed device can be called Yielding Octagonal Connection (YOC), which is modeled using Abaqus finite element software and exposed to cyclic loading according to the ATC-24 code. A bilinear stress-strain curve for steel is used for the modeling. When the hysteresis and envelope curves are obtained, the structure equipped with YOCs is designed using SAP2000. To investigate the behavior of this energy absorption device, a non-linear time history analysis (NLTHA) is conducted for 16-storey steel structures with regular plans and concentrically braced frames (CBFs) under near- and far-field earthquakes. The results of analyses indicate 68 % and 65 % decrease in the maximum base reaction, 79 % and 82 % decrease in the maximum roof story acceleration, 60 % and 58 % decrease in the maximum displacement at roof level under near and far-field earthquakes, respectively. 10.18720/MCE.94.4 finite element method yielding octagonal connection concentrically braced frames non-linear time history analysis near and far-field earthquakes https://engstroy.spbstu.ru/article/2020.94.4/
RAR RUS 54-64 Petersburg State Transport University Gavrilov Timmo gtimmo@mail.ru Petrozavodsk State University Kolesnikov Gennady kolesnikovgn@yandex.ru Evolving crack influence on the strength of frozen sand soils The object of the study in this work is the relationship between the elastic modulus, tensile stresses and deformations of frozen sandy soil with evolving cracks using the example of three-point bending. The goal is to develop a methodology for determining the modulus of elasticity and tensile stresses in frozen sandy soil under force indirectly. The choice of the object and the purpose of the study is motivated by the relevance of the soil strength problems during seasonal freezing. To achieve the goal, methods of mathematical modeling of mechanical systems with changing characteristics during the deformation, also the testing methods of samples on the SHIMADZU AGS-X test machine were used. A mathematical model has been developed, the realism of which is ensured by taking into account the evolution of a crack and using the effective geometric characteristics known from fracture mechanics. It has been substantiated that the destruction of the material occurs on the descending branch of the «load - displacement» diagram. The simulation results are consistent with the data known in the scientific literature. The condition for the model application is the existence of an extremum point on the curve «load - displacement». Prospects for the development of the topic are associated with the adaptation of the proposed approach to the analysis of the of frozen soil state, taking into account its rheological properties. 10.18720/MCE.94.5 mechanical properties elastic moduli tensile strength cracks bending tests experimental investigations mathematical modeling https://engstroy.spbstu.ru/article/2020.94.5/
RAR RUS 65-80 https://orcid.org/0000-0003-0747-7082 Kazan (Volga region) Federal University Maklakov Dmitry dmaklak@kpfu.ru
Kazan, Russia
 https://orcid.org/0000-0003-0369-3693 Kazan State University of Architecture and Engineering Posohin Vladimir posohin@mail.ru
Kazan, Russia
 7004260284 https://orcid.org/0000-0002-7127-1188 Kazan State University of Architecture and Engineering Safiullin Rinat safiullin_rinat@mail.ru
Kazan, Russia
 57216545677 0000-0002-9497-349X Kazan State University of Architecture and Engineering Kareeva Julia jkareeva2503@gmail.com
Kazan, Russia
 Intake rate through openings in the side wall of the duct Subject. In technological and general ventilation ducts with a given uniformity of intake is often needed to be designed. The calculation of pressure losses in such ducts is complicated by the lack of reliable information about the characteristics of the flows at the inlet to the intake openings and slots. Intensity of air intake through slot openings located on one and two opposite walls of the duct in a series of sequentially placed slots, which determines the presence of a transit air stream passing by the hole is calculated. The slots are perpendicular to the generatrix panel and can be opposite or offset relative to each other. The presence of a stagnant zone formed when the flow is cut off from a sharp edge at the inlet is taken into account. Methods. The search for a solution is carried out in the framework of ideal fluid jets theory using the Kirchhoff scheme and Chaplygin method of singularities, as well as by the numerical method using Flow3d software package, where the system of equations of plane turbulent motion was ended with “standard” k-e model. Results. The flow rates of the air entering through the slots were found, depending on their width and value of the transit flow. Dependencies for the attached flow with and without flow separation are obtained. The shape of the free streamline separating the jet and vortex zones, the compression coefficients of the jet are determined. Current flow lines are constructed for different values of the geometric parameters of the duct and the hole. Conclusion. Analytical and numerical calculations showed that the kinematics of currents and values of the attached flow rate are very similar, but the size and shape of the stagnant zone are significantly different. A numerical solution gives more physics of stagnant zone formation. It was found that flow separation reduces the associated flow rate. It was also found that the intensity of absorption is minimal with the opposite order of cracks. 10.18720/MCE.94.6 intake ducts openings in the side wall intake rate ideal fluid conformal mappings numerical calculation https://engstroy.spbstu.ru/article/2020.94.6/
RAR RUS 81-92 https://orcid.org/0000-0002-3065-1192 Karamanoglu Mehmetbey University Karaburc Seyma Nur seymanurkaraburc@gmail.com
Karaman, Turkey
 https://orcid.org/0000-0001-5702-807X Karamanoglu Mehmetbey University Yildizel Sadik Alper sayildizel@kmu.edu.tr
Karaman, Turkey
 https://orcid.org/0000-0001-7196-9407 Karamanoglu Mehmetbey University Calis Gokhan gokhancalis@kmu.edu.tr
Karaman, Turkey
 Evaluation of the basalt fiber reinforced pumice lightweight concrete This paper aimed to investigate the mechanical and durability properties of basalt fiber reinforced pumice lightweight concrete (BPLC) containing nano ground calcium carbonate (GCC). GCC was utilized as ordinary Portland cement replacement material at the percentages of 5 %, 10 %, 15 %, 20 % and 25 %, and basalt fibers with the 6 mm length were added in two contents of 0.5 % and 1 % by volume. The experimental results showed that GCC added mixes had lower mechanical strength results at the early ages; however, comparable strengths with the reference mixes at later ages. The addition of GCC addition also resulted in decreased water absorption, sorptivity and increased magnesium sulphate resistance compared to the reference lightweight concrete. Basalt fiber utilization enhanced the mechanical properties of the BPLC, but fiber inclusion lessened the fresh concrete properties. With respect to the enhanced material properties and less cement usage with produced BPLCs, it can be suitable for the green concrete block production industry. 10.18720/MCE.94.7 lightweight concrete ground calcium carbonate basalt fiber cement https://engstroy.spbstu.ru/article/2020.94.7/ 07.pdf
RAR RUS 93-107 6504446571 0000-0001-6981-7420 Jordan University of Science and Technology Al-Rousan Rajai rzalrousan@just.edu.jo
Irbid, Jordan
 Behavior of strengthened concrete beams damaged by thermal shock In the last two decades, using of Carbon Fiber Reinforced Polymers (CFRP) in strengthening of deficient reinforced concrete structural elements has been increased due to their ease of installation, low invasiveness, high corrosion resistance, and high strength to weight ratio. Strengthening damage structures is a relatively new technique. The aims of this study is to investigate the effectiveness of using CFRP to regain shear capacity of shear-deficient reinforced concrete (RC) beams after being damaged by thermal shock. Firstly, a novel Nonlinear Finite Element Analysis (NLFEA) model is created and validated. Then, Ten RC beams (100×150×1400 mm) have been constructed and divided into two groups to scrutinize the effect of CFRP strip number and thermal shock impact. The performance of each beam was evaluated in terms of failure mode, CFRP strain, load-deflection behavior, ultimate deflection, ultimate load capacity, elastic stiffness, toughness, performance factor, and profitability Index of the CFRP Strips. Load carrying capacity and stiffness of RC beams decreased about 68 % and 71 %, respectively, as compared with reference un-damaged beam. Strengthening the thermal damaged RC beams allowed recovering the original load carrying without achieving the original stiffness. Strengthened beams with fully CFRP plates regained the original load capacity with a corresponding stiffness from 79 % to 105 %, respectively. Finally, the enhancement percentage increased with the increase of bonded area or number of CFRP strips and these percentages sharply dropped for damaged beams. 10.18720/MCE.94.8 reinforced concrete thermal shock structural strength shear flexural strength fiber reinforced polymer nonlinear finite element analysis https://engstroy.spbstu.ru/article/2020.94.8/ 08.pdf
RAR RUS 108-119 55987932400 https://orcid.org/0000-0002-0312-4960 Universitas Sebelas Maret Kristiawan Stefanus s.a.kristiawan@ft.uns.ac.id
Surakarta, Indonesia
 57195315791 Universitas Sebelas Maret Supriyadi Agus agussupriyadi@staff.uns.ac.id
Surakarta, Indonesia
 Two-way patched RC slabs under concentrated loads Damage that occurs in reinforced concrete elements can reduce the capacity and serviceability of these elements. One of the damages that may be encountered is spalling or delamination of concrete covers. Repairs to this type of damage can be carried out by patching methods. This research uses unsaturated polyester resin mortar (UPR-mortar) as a patch repair material to recover the damage of two-way slabs. Laboratory investigations were carried out to determine the effects of variations in patching location and loading on the ultimate capacity. The development of crack patterns as the load increases, the final yield lines formed at the time of collapse, and the magnitude of the ultimate load are the main data discussed in this research. In addition, load-deflection behavior, stiffness and toughness are also presented and discussed. Yield Line Theory (YLT) has been applied using virtual work principle with several assumptions and simplifications to estimate the ultimate load of the slabs. The experimental results show that UPR-mortar is able to recover the capacity and stiffness of the damaged slab, but it can not restore the toughness to the original level. The theoretical strength of the patched repair slabs estimated by simplified YLT shows that it is at least 90 % compared to experimental results. 10.18720/MCE.94.9 patching slab spalling ultimate load unsaturated polyester resin mortar yield line https://engstroy.spbstu.ru/article/2020.94.9/ 09.pdf
RAR RUS 120-128 0000-0002-7812-3540 Riga Technical University Zemitis Jurgis jurgis.zemitis@rtu.lv
1 Kalku Street, Riga LV-1658, Latvia
 Riga Technical University Bogdanovics Raimonds Raimonds.Bogdanovics@rtu.lv
Riga, Latvia
 Heat recovery efficiency of local decentralized ventilation devices Decentralized, room-based ventilation systems have become increasingly popular in the Baltic countries. Such systems are easy to install and, according to technical information, ensure high heat energy recovery potential for new and renovated buildings. The specified heat recovery efficiency is used for building energy simulations and to calculate the necessary heating energy that is needed to warm up the supply air. However, this value is stated at non-existent pressure difference between indoor of the building and the outside. In real-case situations, there is always some pressure difference due to wind and stack effect. In this study, a ventilation device is tested in a laboratory environment at different simulated outside air temperatures and pressure differences. The simulations are conducted in a climatic chamber where the air temperature and pressure differences can be set. The temperature is adjusted using a cooling device but the pressure difference with an exterior fan device. Different combinations of simulated outside air temperatures and pressure differences were tested. The results suggest that the heat recovery efficiency is highly dependent on the pressure difference and it rapidly decreases with the rise in pressure difference. If the pressure difference is in the range of 10–20 Pa, the heat recovery efficiency will be only between 20 and 50 %, while the stated value in the technical data sheet is 85 %. Even at a pressure difference of 0 Pa, the average heat recovery efficiency is 73 %, and only for the first few seconds of the supply cycle, the efficiency reaches 85 %. This can influence the calculated building energy efficiency class, as well as lead to undersized heating system elements. 10.18720/MCE.94.10 decentralized ventilation heat recovery efficiency pressure difference https://engstroy.spbstu.ru/article/2020.94.10/ 10.pdf
RAR RUS 129-144 7005883981 https://orcid.org/0000-0002-8977-5130 New Millennium Building Systems Degtyarev Vitaliy vitaliy.degtyarev@newmill.com
Columbia, SC, USA
 Finite element modeling of cold-formed steel deck in bending Finite element simulations of structural members are a good alternative to physical testing for studying strength and structural response of the members when finite element models have been properly calibrated and validated. Published information on finite element modeling of cold-formed steel deck in bending is scarce. This paper presents the development of finite element models of corrugated steel deck in bending using a general-purpose software, ANSYS. Effects of the following parameters on elastic buckling and ultimate moments of models, as well as on their load-deflection curves, were studied: shell element types, mesh density, corner radius, number of deck corrugations, presence of transverse ties, initial geometric imperfection distribution and magnitude, deck boundary conditions, loading type, and stress-strain diagrams. Optimal parameters of the models were determined. Moment capacities, flexural stiffness, and load-deflection curves predicted by the models with the optimal parameters correlated well with test results available in literature, especially when the deck material behavior was described by nonlinear stress-strain diagrams. The developed FE models can be used for studying flexural strength and behavior of solid steel deck with various geometry under various loading types, which can be useful in development of new efficient profiles and in improving the current deck design methods. The models can also be used as a basis for the development of FE models of steel deck with openings and acoustical perforations, as well as built-up deck profiles, design methods for which are currently underdeveloped. 10.18720/MCE.94.11 cold-formed steel deck flexural behavior buckling bending strength finite element method numerical methods ANSYS https://engstroy.spbstu.ru/article/2020.94.11/ 11.pdf
RAR RUS 145-157 0000-0003-3750-5005 Czech Technical University Bily Petr petr.bily@fsv.cvut.cz
Thakurova 7, 166 29 Prague, Czech Republic
 0000-0001-8281-3053 Czech Technical University Fladr Josef fladr@fsv.cvut.cz
Thakurova 7, 166 29 Prague, Czech Republic
 0000-0001-5497-0705 Czech Technical University Chylik Roman chylik@fsv.cvut.cz
Prague, Czech Republic
 Czech Technical University Hrbek Vladimir hrbek@fsv.cvut.cz
Thakurova 7, 166 29 Prague, Czech Republic
 Czech Technical University Vrablik Lukas vrablik@fsv.cvut.cz
Thakurova 7, 166 29 Prague, Czech Republic
 Micromechanical characteristics of high-performance concrete subjected to modifications of composition and homogenization The paper deals with the effect of various modifications of composition and homogenization procedure on micromechanical characteristics of high-performance concrete (HPC) containing supplementary cementitious materials (SCMs), namely silica fume, fly ash and metakaolin. The main motivation was to characterize the changes of microstructure induced by the type and amount of SCMs, by the time and order of mixing of components and by coarse aggregate washing. The effects of the changes of microstructure on macroscopic mechanical features of the material were also studied. Indentation moduli of particular phases of the material were measured by nanoindentation. Interfacial transition zone (ITZ) thickness was primarily measured by nanoindentation. An alternative method of ITZ thickness determination based on variations in chemical composition was tested for a selected sample with encouraging result. Compressive strength and bulk elastic modulus of concrete were determined by standard loading tests. The results showed that SCMs generally decrease the thickness of ITZ, but no direct relation to compressive strength of concrete was found for mixtures with variable SCMs content. In case of mixtures with optimized SCMs content prepared by different homogenization procedures or with the use of aggregate washing, qualitative dependence between ITZ thickness and compressive strength was found. Aggregate washing proved to be useful for improving both microscopic and macroscopic properties, having positive effect on ITZ thickness, compressive strength, bulk elastic modulus and indentation moduli of particular phases. 10.18720/MCE.94.12 high-performance concrete supplementary cementitious materials interfacial transition zone nanoindentation mechanical pro https://engstroy.spbstu.ru/article/2020.94.12/ 12.pdf