Magazine of Civil Engineering

RAR RUS 3-14 Riga Technical University Buka-Vaivade Karina karina.buka.vaivade@gmail.com Riga Technical University Sliseris Sliseris janis.sliseris@rtu.lv 6508223358 Riga Technical University Serdjuks Dmitrijs Dmitrijs.Serdjuks@rtu.lv

1 Kalku Street, Riga LV-1658, Latvia

H-5843-2013 57205122537 0000-0002-8367-7927 Riga Technical University Pakrastins Leonids leonids.pakrastins@rtu.lv M-6585-2013 6508103761 0000-0002-1196-8004 Peter the Great Saint Petersburg Polytechnic University Vatin Nikolai vatin@mail.ru

Polytechnicheskay, 29

Rational use of HPSFRC in multi-storey building Fibres improve concrete properties that can be used to solve the problem of limited resources. This research includes the numerical comparison of high-performance concrete (HPC) and high-performance steel fibre reinforced concrete (HPSFRC) behaviour. The numerical comparison is based on the analyse of stress-strain curves of considered materials. The limits of rational use of HPC and high-performance steel fibre reinforced concrete HPSFRC have been determined based on typical stress resultants values acting in the elements of multi-storey buildings. The values of stress resultants were determined by the numerical model, which was developed by the software ANSYS. Interaction diagrams of bending moments and axial forces M-N for elements subjected to combined action of compression and bending with different cross-sections have been developed. Curves for slabs of two material types that describe the allowable values of distributed load at different spans of the slabs are created. The resulting curves are analysed together with the actual stress resultants of the elements concerned from the numerical model. Taking into account distribution of stress resultants in the elements of multi-storey buildings, it was stated that the elements subjected to flexure are preferable field of application for HPSFRC. Ultimate value of bending moment is higher for HPSFRC comparing to HPC with the same parameters of cross-section. It is found that it is more rational to use HPSFRC for columns in the first eight floors. HPSFRC should be preferred as a material of the lower and middle floors of multi-storey buildings and of the walls of all floors in the case of column spacing more than 8 m, and for the slabs with span interval 6–12 m. 10.18720/MCE.84.1 high-performance concrete highperformance steel fibre reinforced concrete stress–strain curve elements of multi-storey building https://engstroy.spbstu.ru/article/2018.84.1/ 01.pdf

RAR RUS 15-28 St. Petersburg State University of Architecture and Civil Engineering Kaldar-ool Anay-Khaak oorzhaka-h@mail.ru St. Petersburg State University of Architecture and Civil Engineering Babanov Vladimir babanov_vladimir@mail.ru Petersburg State Transport University Allahverdov Boris aborism@mail.ru Additional load on barrel vaults of architectural monuments In old buildings, which are architectural monuments, the stone three-centered barrel vaults and arches have been often used. In case of reconstruction of old buildings, it becomes necessary to increase the load on these elements. Calculation of additional load is based on instrumental examination of the vaults. While creating an analytical model of a barrel vault, it is necessary to use the experimental results of determination of the vault geometric parameters and material strength characteristics. The vault bearing capacity determined on base of analytical estimation is confirmed by similar calculations done by means of software packages, as well as by the data obtained by means of real loading of the vault. The proposed procedure for determination of additional load onto barrel vault may be also used in designing of similar architectural monuments. 10.18720/MCE.84.2 barrel vault method of forces strength stresses deformation modulus of elasticity load https://engstroy.spbstu.ru/article/2018.84.2/ 02.pdf

RAR RUS 29-40 Military Institute of rail transport troops and military communications Kalugin Yuri yuri_kalugin@inbox.ru Military Institute of rail transport troops and military communications Romanov Roman sluzba2013@mail.ru Scheduling workflows for scattered objects As a rule, the task of optimal scheduling, including reducing the total duration of the project occurs when developing and adjusting schedules. The essence of flow shop scheduling problem on the scattered objects with the use methods and models calendar planning was presented. The branch and boundary method were proposed as an exact method for determining the optimal permutation including the scheme of branching and rules for determining the lower boundaries. Heuristic algorithms for determining the optimal sequence of work for scattered objects was substantiated. The general applicability of the algorithms was demonstrated with calculations including 30 variants from distinct flows. The performed studies show the possibility of reducing the planned time by about 15 %. The suggested methodology can be recommended for use by construction project managers. 10.18720/MCE.84.3 civil engineering construction management project scheduling flow shop scheduling problem for scattered objects https://engstroy.spbstu.ru/article/2018.84.3/ 03.pdf

RAR RUS 41-47 Belgorod State Technological University named after V.G. Shukhov Klyuev Sergey Klyuyev@yandex.ru Belgorod State Technological University named after V.G. Shukhov Klyuev Alexander Klyuyev@yandex.ru

Belgorod, Russia

M-6585-2013 6508103761 0000-0002-1196-8004 Peter the Great Saint Petersburg Polytechnic University Vatin Nikolai vatin@mail.ru

Polytechnicheskay, 29

Fiber concrete for the construction industry The article considers the use of dispersed concrete reinforcement. The efficiency of reinforcing of concrete by a fiber is proved as its strength and deformative characteristics increase. For receiving composite binders were used: Portland cement of TsEM I 42.5H GOST 31108-2003 (Russian State Standard), blast furnace granulated slag with Mo = 1.14 and Ma = 0.2, mineral plasticizer Tricosal 181 softener in essence supplementing particle size distribution knitting, waste of wet magnetic separation of ferruterous quartzites (WMS). Different types of composite binders were developed and their physicmechanical characteristics are defined. For disperse reinforcing alkaliproof glass fiber was chosen; it is produced in the form of a roving. The analysis of results showed positive influence of the composite binders on mixes strength characteristics. The microstructure of mixes on the basis of composite binders has significant effect on properties of a composite. The conducted researches showed that the most effective length of a glass fiber is 12 mm, percent of reinforcing – 4.5 % on weight at the relation of cement and sand equal 1:3. Optimum selection of filler and also use of fiber glass in an optimum dosage allowed to increase concrete durability by stretching at a bend for 172 % on a Portland сement and to 225 % on composite binders that allows to apply it to designs. 10.18720/MCE.84.4 composite binders fibre concrete blast furnace granulated slag fiber reinforcement https://engstroy.spbstu.ru/article/2018.84.4/ 04.pdf

RAR RUS 48-56 56662851300 0000-0001-8407-8144 Ogarev Mordovia State University Erofeev Vladimir al_rodin@mail.ru 57191249816 0000-0002-8080-9808 Ogarev Mordovia State University Rodin Alexander al_rodin@mail.ru Ogarev Mordovia State University Kravchuk Aleksej a.kravchuk.s@yandex.ru Ogarev Mordovia State University Kaznacheev Sergej kaznacheevsv@rambler.ru Lobachevsky State University of Nizhni Novgorod Zaharova Elena zaharova_elena_aleksandrovna@mail.ru Biostable silicic rock-based glass ceramic foams The search for the possibility of expanding the resource base through the use of local rocks, as well as reducing the cost of final product, is one of the scientific research areas in the field of obtaining foam glass-based building materials. The aim of the research is the development of compositions and recommendations for the production of silicic rock-based glass ceramic foams. These studies will allow to create strong and durable building materials with low density and thermal conductivity, as well as increased biological stability. The results of studying the phase transformations occurring in the charge (tripoli : soda ash) during heating, obtained by thermal analysis methods are presented as well as the production technology, physico-mechanical and thermophysical properties of the developed glass ceramic foams. As a result, construction materials resistant to aggressive media with a density of 200 to 600 kg/m3, thermal conductivity from 0.053 to 0.115 W/m∙°C, compressive strength from 1.2 to 9.8 MPa, have been developed. Due to its properties, developed glass ceramic foams will be used primarily as insulants for the construction of nuclear power plants, in the gas and oil industries, industrial and civil engineering. 10.18720/MCE.84.5 glass ceramic foams thermal insulation material biostability silicic rock https://engstroy.spbstu.ru/article/2018.84.5/ 05.pdf

RAR RUS 57-66 55516020800 Northeast Forestry University Zhao Qianqian 492954791@qq.com

Harbin Heilongjiang, China

55434335600 Northeast Forestry University Cheng Peifeng chengpeifeng@126.com Harbin Dongan Automobile Engine Manufacturing Co,Ltd. Wang Jianwu nihaone@163.com 57204285919 Yellow River Survey Planning and Design Co., Ltd. Wei Yuwei weiyuwei1991@qq.com Damage prediction model for concrete pavements in seasonally frozen regions Vehicle loads and environmental differences are the key technical factors in the model construction of concrete pavement damage prediction. According to the data of the 168-month actual number of actions of different vehicle axle types, average temperature, average wind speed, rainfall, snowfall and days below 0 ℃ collected from the Mudanjiang-provincial section of the He-da highway in China, the broken slab ratio of cement concrete (DBL) was calculated. Cracking rate(CRK) and environmental factor(SF) were introduced into the model. This paper uses SPSS analysis method to carry out correlation analysis and partial correlation analysis by introducing SF to the model of DBL and CRK, so that the concrete pavement damage prediction model in seasonally frozen regions can be constructed and tested. Results show that CRK and SF both have positive linear relationship with DBL; Concrete pavement damage in seasonally frozen regions can be predicted by analyzing parameters like actual number of actions of different vehicle axle types, road service time and freezing index, etc. No multiple collinearity exists in the parameters of the model and the construction of model for concrete pavement damage prediction in seasonally frozen regions is of great theoretical significance for timely and effective pavement maintenance. The model has achieved good results in damage prediction accuracy and efficiency. 10.18720/MCE.84.6 concrete pavement damage prediction environmental factor statistical product and service solution https://engstroy.spbstu.ru/article/2018.84.6/ 06.pdf

RAR RUS 67-74 AAU-2845-2020 57204362749 0000-0002-6289-325X Peter the Great St. Petersburg Polytechnic University Sergeev Vitaliy vicerector.sc@spbstu.ru

St. Petersburg, Russia

56426211200 0000-0002-3541-0072 Peter the Great Saint Petersburg Polytechnic University Petrichenko Mikhail fonpetrich@mail.ru

Polytechnicheskay, 29

56227381900 0000-0003-2673-4566 Peter the Great Saint Petersburg Polytechnic University Nemova Darya darya.nemova@gmail.com

Polytechnicheskay, 29

Peter the Great St. Petersburg Polytechnic University Kotov Evgeny ekotov.cfd@gmail.com

St. Petersburg, Russia

Peter the Great Saint Petersburg Polytechnic University Andreeva Darya tarasovads@gmail.com

Polytechnicheskay, 29

Peter the Great Saint Petersburg Polytechnic University Nefedova Anna anyanefedova94@mail.ru

Polytechnicheskay, 29

AAV-2280-2020 48361113100 0000-0001-9004-7889 Riga Technical University Borodinecs Anatolijs anatolijs.borodinecs@rtu.lv

Riga, Latvia

The building extension with energy efficiency light-weight building walls The effective use of plan area is more crucial in high-rise buildings, since they are mostly narrow compared to the conventional buildings. The measurement of the overall thermal transmittance of lightweight steel-framed walls, including the effect of thermal bridges due to metal structure, is a challenge for designers, engineers and energy audits. In this paper the energy efficiency light-weight wall technology for over story of buildings was considered. In this work was developed a mathematical model of non-stationary heat transfer through the enclosing wall using the lightweight wall technology and evaluated the efficiency of various designs of lightweight wall. In this model, the profile perforation is taken into account due to the results of the solution of the test problem while maintaining the possibility of using structured grids with the number of elements not exceeding 1 million, which allowed to obtain more accurate results. 10.18720/MCE.84.7 light wall light steel thin-walled structures energy efficiency civil engineering buildings construction https://engstroy.spbstu.ru/article/2018.84.7/ 07.pdf

RAR RUS 75-85 56826013600 Peter the Great St. Petersburg Polytechnic University Gravit Marina marina.gravit@mail.ru

29 Politechnicheskaya St., St. Petersburg, 195251, Russia

Peter the Great Saint Petersburg Polytechnic University Golub Elena alen-go@bk.ru

Polytechnicheskay, 29

LLC «Fire Safety Technology» Grigoriev Denis gdm@pptech.ru LLC «Fire Safety Technology» Ivanov Igor info@pptech.ru Fireproof suspended ceilings with high fire resistance limits Suspended ceiling is an effective way to fire protection of horizontal structures with steel beams due to its lightness, reliability and functionality. Three designs of fireproof suspended ceiling with silicate plates on cement binder are considered. A detailed description of the tested structures is given. Experiments were carried out to determine the fire resistance of the samples. The results of fire tests on suspended ceilings under standard fire temperature regime are presented in this study. It was found that the structures that have shown their effectiveness under the standard regime cannot satisfy the conditions of the hydrocarbon temperature regime. For the purpose of efficiency in the hydrocarbon regime and isolating the beams from the fire, in addition to fire-retardant plates, non-combustible heat insulation was used in the construction of the ceiling. The results of testing the ceiling with fire-retardant plates and rock wool when creating a hydrocarbon fire regime are given. It is shown that at the end of the fire exposure, the limiting state of the loss of bearing capacity and the loss of integrity was not fixed, visible changes during the test period was not found. 10.18720/MCE.84.8 oil and gas complex building structure steel construction fire resistance hydrocarbon fire standard fire suspended ceiling https://engstroy.spbstu.ru/article/2018.84.8/ 08.pdf

RAR RUS 86-96 Tomsk State University of Architecture and Building Steshenko Aleksei steshenko.alexey@gmail.com Tomsk State University of Architecture and Building Kudyakov Aleksandr kudyakow@mail.tomsknet.ru Cement based foam concrete with aluminosilicate microspheres for monolithic construction The present paper investigates cement foam concrete of natural hardening with aluminosilicate microsphere made from bottom ash waste from Seversk Heat and Power Station in Tomsk Region. The relevance of the given study is conditioned by the necessity to provide the required process parameters of mixture for transportation and laying the formwork, as well as providing strength and thermal and physical characteristics of wall structures for economy-class housing construction. Porous microsphere from bottom ash wastes applied within the technology of cement foam concrete of natural hardening contributes to ensuring increased microporosity and strength of interpore partitions of foam concrete. The study was conducted in the Laboratory of Tomsk State University of Architecture and Building which is accredited in accordance with the national standards requirements. The optimal content of microsphere in the cement foam concrete mixture was 5–10 % of the cement weight. Foam concrete mixture with microsphere possesses higher flowability and concrete has reduced plastic shrinkage by 40 %. The average pores diameter in foam concrete with microspheres is reduced from 308 to 210.2 µm, mean square deviation of the pores diameter is reduced from 23.6 to 14.2 µm. The maximum effect of reducing thermal conductivity coefficient up to the value of 33 % is observed with 5 % microsphere content of the cement weight. Inclusion of microsphere within the process of mixture formation enables to increase concrete strength at the age of 28 days by 40 % and its softening coefficient by 15 %. The elaborated composition and technology of foam concrete production with aluminosilicate microsphere is intended for use in the walls structures in monolithic construction. 10.18720/MCE.84.9 foam concrete mixture microsphere plastic shrinkage average density porosity strength softening coefficient thermal conductivity monolithic construction https://engstroy.spbstu.ru/article/2018.84.9/ 09.pdf

RAR RUS 97-101 57195684636 0000-0001-8800-2657 Voronezh State Technical University Slavcheva Galina gslavcheva@yandex.ru Voronezh State Technical University Artamonova Olga ol_artam@rambler.ru Rheological behavior of 3D printable cement paste: criterial evaluation The extrudability and firm stability are the criterial rheological characteristics of building 3D printable mixtures. From the point of view of classical rheology of disperse systems, the theoretical analysis of the rheological behavior of a cement paste has been analyzed for all stages of 3D printing process. Apparently both the theoretical analysis criteria and technological tools to control rheological behavior of a 3D printable mixture have been justified. The squeezing test is used in the experimental research as a rheological behavior identification tool of cement-based materials, in order to evaluate the extrudability and buildability. The squeezing test, with constant plate speed, is determining plastic yield value and elasticity criterion of a cement paste as criteria of the extrudability. The squeezing test, with constant strain rate, is determining structural and plastic strength, plastic deformations as a criteria for the ability of a cement paste to hold shape during multi-layer casting. It is shown that these properties are significantly controlled by the W/C-ratio, concentration of plasticizer additives as factors of changes in the concentration of the dispersed phase and properties of the dispersion liquid in a system «cement + water» as matrix for printing concrete. 10.18720/MCE.84.10 3D build printing cement paste rheology squeezing test extrudability buildability https://engstroy.spbstu.ru/article/2018.84.10/ 10.pdf

RAR RUS 109-118 South Ural State University Kiyanets Aleksandr kiyanets2007@mail.ru Concrete with recycled polyethylene terephthalate fiber The purpose of this study was to obtain the data on the influence of fiber from the products of recycled polyethylene terephthalate (PET) on the strength properties of fiber-reinforced concrete. In the experiments, used the direct product of industrial recycling of plastic bottles (flex), as well as specially prepared smooth and ribbed fiber from the same raw material. The influence factors were chosen fiber length from 1 to 5 cm and the amount of fiber-from 1 to 3 % by weight of cement. It has been found that the use of PET fibers provides a gain in the concrete tensile strength of up to 66 %. The compressive strength of the studied samples of fiber-reinforced concrete within the limits of the varying factors decreased by 3–25 %. The most favorable ratio of the increase in the bending tensile strength and the decrease in the compressive strength was obtained in concrete with the addition of smooth 4cm long fiber with the smallest reinforcement value. The abrasion capacity (abrasive wear) of the samples decreased with the addition of 3 % of smooth and ribbed 4 cm long fiber. The research resulted in the experimental determination of the effective fiber length (critical fiber length) providing the most reliable fastening of the fiber in the concrete matrix. 10.18720/MCE.84.11 polyethylene terephthalate PET PET recycling fiber flex PET fiber-reinforced concrete fiber concrete https://engstroy.spbstu.ru/article/2018.84.11/ 11.pdf

RAR RUS 119-129 Siberian State University of Railway Engineering Bokarev Sergey bokarevsa@stu.ru Siberian State University of Railway Engineering Zhunev Kirill junev.kirill@yandex.ru Siberian State University of Railway Engineering Usol’tsev Andrey uam@stu.ru Stress-strain behavior of welded joints in railway girders A metal construction with welded joints often fails under repeated loads by fatigue. Fatigue cracks at welded joints occur because real stress-strain behavior of welded joints is not taken into consideration by standard design. The article is devoted to the stress behavior determination of welded joints in railway girders under external loads and residual stresses. Design deficiencies and technological features of welded girders were identified. These features may increase stresses at welded joints and decrease fatigue life. As a result of studying the existing methods for determining stresses in welded joints, authors used a method, that takes into account the residual welding stresses and design features of welded girder. In this study, the stresses were determined in a cracking area of a girder with the help of finite element modeling. It was shown the correspondence of the stresses in the finite element model and the real girder, tested under the moving load. Retrofitting of stiffeners in welded girders with fatigue cracks was carried out using corner plate connected tightly stiffener and beam flange. Strain measurements under the moving load before and after the retrofitting near cut ribs were taken. The dependence of the stresses at the beam webs was demonstrated near the upper welded ends of stiffeners on the stiffness of rib connections to beam flanges. These findings can be useful at the fatigue life design of the welded elements at building constructions. 10.18720/MCE.84.12 railway bridge welded span fatigue crack finite element method residual stresses reinforcement https://engstroy.spbstu.ru/article/2018.84.12/ 12.pdf

RAR RUS 130-137 0000-0002-7812-3540 Riga Technical University Zemitis Jurgis jurgis.zemitis@rtu.lv

1 Kalku Street, Riga LV-1658, Latvia

AAV-2280-2020 48361113100 0000-0001-9004-7889 Riga Technical University Borodinecs Anatolijs anatolijs.borodinecs@rtu.lv

Riga, Latvia

Riga Technical University Lauberts Austris austris.lauberts@gmail.com Ventilation impact on VOC concentration caused by building materials Many of building products emit volatile organic compounds (VOCs) therefore reducing the indoor air quality. The emitted amount and pollution type depends on each specific source. This paper analyses the VOC concentration change caused by such sources as sprayable window cleaner, aroma candles, sprayable air refresher, waterborne acryl-based paint, solvent based paint and acrylic based hermetic sealant. The tests are done at both closed and ventilated climatic chamber conditions. The results show that three different types of VOC concentration change dynamics can be separated depending on the pollution source. If the room is ventilated according to the local regulations the threshold level which indicates hazardous environment for persons is exceeded for 12 hours after applying the pain at given conditions. The obtained data can be used for future studies and to develop high precision methods of VOC concertation prediction and serve as an information source for future ventilation standard development. 10.18720/MCE.84.13 VOC ventilation buildings climatic chamber indoor climate acryl-based paint solvent based paint acrylic based hermetic sealant https://engstroy.spbstu.ru/article/2018.84.13/ 13.pdf

RAR RUS 140-149 North-Eastern Federal University named after M.K. Ammosov Kornilov Terentii kornt@mail.ru North-Eastern Federal University named after M.K. Ammosov Nikiforov Alexsandr nialyk@mail.ru Thermal protection of low-rise buildings from light steel thin-walled structures Thermal protection providing of frame buildings in the extreme conditions of the Far North depends on air infiltration. Elements of buildings frame on light steel thin-walled structures (LSTS below) technology – lightweight, thin-walled steel profiles make up multiple thermal bridges. The basic principles of designing the exterior walling of low-rise buildings from LSTS in the Far North are developed with taking into account the increased air infiltration and the heat transfer components and assemblies. The construction with double insulation layer and the intermediate airtight barrier of particleboard, the indicative panels (OSB below) are proposed as the exterior walls. The concrete ground slab and thermofiller using of lightweight concrete blocks are recommended in buildings with pile foundation. The two-stage disposition of blocks between the steel frame elements and the basement ceiling allow to overlap joints of thermal insulation materials with other structural elements which reduces the impact of air infiltration. The specific heat loss values for a multilayer wall construction and assembly of its coupling with a ground overlap, depending on various parameters are obtained with the calculating program application of threedimensional temperature fields. 10.18720/MCE.84.14 thermal protection infiltration temperature light steel thin-walled structures cold bridges wall structures basement floor https://engstroy.spbstu.ru/article/2018.84.14/ 14.pdf

RAR RUS 150-161 Astrakhan State Architectural and Construction University Zolina Tatiana zolinatv@yandex.ru Astrakhan State Architectural and Construction University Sadchikov Pavel pn_sadchikov@mail.ru Residual resource of a one-storey steel frame industrial building constructed with bridge cranes The scheme of an integrated approach to the study of changes in the stress-strain state of the frame one-story industrial building constructed with bridge cranes, caused by accumulation of damage caused during the operation. The algorithm has been developed for estimating and predicting the residual resource of a production facility on the basis of processing the results of a series of surveys. It allows to obtain the values of reliability indicators in the correlation approximation using probabilistic models of disturbing influences. This approach is based on the assessment of the reserve strength of the framework structures, determined by the difference between their bearing capacity and the largest value of the generalized load. The article demonstrates the numerical implementation of the algorithm on the example of calculating the building of the shipbuilding shop of a marine shipbuilding plant. Consistent solution positive, negative and predictive tasks enabled by analyzing the dynamics of natural frequencies building frame under the action of the aggregate load estimate time reaches the maximum allowable state. The results allow to regulate the timing and direction of the actions of the repair work at lower 4...8 times the intensity of the survey. 10.18720/MCE.84.15 industrial building Residual resource probabilistic model system of reliability coefficients stress-strain state matrix of rigidity https://engstroy.spbstu.ru/article/2018.84.15/ 15.pdf

RAR RUS 162-172 57200287767 Siberian Federal University Koyankin Alexandr KoyankinAA@mail.ru 12795222600 Novosibirsk state University of architecture and construction Mitasov Valery mitassovv@mail.ru Siberian Federal University Tskhay Trofim vadershow@gmail.com Compatibility of precast heavy and monolithic lightweight concretes deforming Safe performance of connecting joint applied to different concrete ages is highly important when joints is placed in composite structures since joint is involved in mutual deformation of precast and monolithic concretes. This experimental study was carried out to determine how type of joint influence on it bearing capacity when perceiving shearing forces. The tests were carried out on a specially manufactured horizontal bench and a vertical press, which provided a shear force in the samples of different ages and with different concrete strength (light monolithic and heavy precast concretes). The following options of the joint were considered: a smooth surface, where the connection is done only by the forces of adhesion and friction; a joint with keys, the spacing of which varied; and a joint with the use of cross reinforcement. This paper determines nuances of the load-bearing capacity exhaustion in a composite structure at shear depending on the type of joint of lightweight monolithic and heavy precast concrete. A comparative analysis of the results obtained in the experimental studies and the data of previous studies has been carried out. The highest bearing capacity under shearing loads was determined in the joint with the cross reinforcement. Moreover, it was noted that keyed connection of concretes let guarantee sufficiently safe performance of connection. 10.18720/MCE.84.16 reinforced concrete structures precast and monolithic structures lightweight concrete connection of monolithic and precast concrete keyed connection of concretes shear strength https://engstroy.spbstu.ru/article/2018.84.16/ 16.pdf

RAR RUS 173-191 National Research Moscow State Civil Engineering University Lam Tang lamvantang@gmail.com

Moscow, Russia

National Research Moscow State Civil Engineering University Vu Dinh vuthoks@gmail.com National Research Moscow State Civil Engineering University Vu Kim Dien kimdienxdtb@gmail.com National Research Moscow State Civil Engineering University Bulgakov Boris fakultetst@mail.ru National Research Moscow State Civil Engineering University Korol Elena korolea@mgsu.ru Properties and thermal insulation performance of light-weight concrete The building energy performance is becoming increasingly important, because of environmental restrictions and rising costs of fuel end energy. Therefore, improve the thermal insulation performance of wall covers of buildings is crucial. The present study evaluated the combined effects of two types of materials of expanded polystyrene (EPS) beads and unprocessed fly ash (FA) in Vietnam on properties of light-weight concrete (LWC). The calculation of mixture proportions of LWC is applied in accordance with the absolute volume method. Twelve different concrete mixtures with a water to bind ratio of 0.3 and superplasticizer SR 5000F to Portland cement ratio of 0.02 were used. The EPS beads and FA were partially replaced with the volume of fresh concrete and cement, respectively. The engineering properties, including workability, density, compressive strength, tensile strength, modulus of elasticity and basic physical properties were investigated in 12 patterns of tested LWC and its correlations were made. In addition, the definition of temperature distribution over the thickness of the experimental wall cover was applied by the ANSYS 18 software. According to the experimental results, there is a decrease in dry density and mechanical properties with increasing these EPS beads and FA contents in LWC. The results by ANSYS 18 are shown that at the same thickness of 250 mm, a wall with the blocks LWC brick has better insulation than the wall made of other materials such as solid clay brick, clay hollow brick and solid brick with slag concrete. 10.18720/MCE.84.17 expanded polystyrene bead unprocessed fly ash light-weight concrete thermal insulation performance temperature distribution wall cover https://engstroy.spbstu.ru/article/2018.84.17/ 17.pdf

RAR RUS 192-204 National Research Moscow State Civil Engineering University Phuong Nguyen phuongntk@nuce.edu.vn Luminance distributions in the tropical sky conditions Lighting engineering in construction is a complex scientific field, which requires the amalgamation of knowledge in the field of daylighting, construction and architecture, as well as other areas, including the humanities. Many studies have proven the benefits of natural light on health, activity, visual well-being and human productivity. Global environmental issues and the sustainable development movement require architectural design to achieve maximum energy efficiency. For all intents, daylighting calculations depend on the luminance distributions of the sky types. Currently, standard documents are used for the luminance distribution and daylighting calculations under overcast sky conditions in Vietnam, where the overcast sky and clear sky are not typically considered. For these reasons, an update of theoretical studies in the daylighting calculations and design the daylighting systems must be completed. Accordingly, this study offers the modern methods of analyzing the firmament luminance distributions when calculating Daylight Factor on the more realistic sky conditions. For this, the sky type have to be defined according to the location. Fifteen international standard types of the firmament with their descriptors are provided by Kittler et al. and a technique using a relation of diffuse and total solar illuminance levels named the cloudiness coefficient Ko are considered to define the sky condition in Hanoi and Ho Chi Minh City. As the results, the typical sky type for Hanoi is the partly cloudy sky no gradation towards zenith, slight brightening towards the Sun; when the sky type for Ho Chi Minh City is the partly cloudy, with brighter circumsolar region. From these results, the sky luminance distributions for daylighting calculations were proposed. A comparison shows the difference between these calculations can be allowed at the altitude angles γ of a point in the sky above 50o with the relative errors below 10 %. The method offered and verified in this study showed that, it has potential to be used for difference climate areas. 10.18720/MCE.84.18 daylight climate firmament types sky luminance distributions cloudiness coefficient daylighting calculations https://engstroy.spbstu.ru/article/2018.84.18/ 18.pdf