33407 2304-6295 Construction of Unique Buildings and Structures 5 90 2020 1-49
RAR RUS 9001-9001 0000-0002-2469-0910 Saint-Petersburg Mining University Dashko Regina
St. Petersburg, Russian Federation
 0000-0002-0455-1462 St. Petersburg State University Vlasov Dmitry
St. Petersburg, Russian Federation
 0000-0003-0885-517X “Georeconstruction” Institute Voronov Alexey
St. Petersburg, Russian Federation
 Negative impact of microorganisms on multicomponent underground space of St-Petersburg: engineering, geological and geotechnical aspects This article considers the problem of improving safety for reconstruction and restoration of historical buildings of 1898-1902s located in Telejnaya St., Saint-Petersburg. The multiple investigation of bearing constructions mentioned above buildings as well as their foundations was made. The geotechnical analysis of foundation soils of the buildings was carried out. The underground water contamination level was assessed, contaminant sources were found. Taking in consideration palustrain deposits widespread occurrence and the term of sewer leakage, microbiological examination of foundation soils of the buildings, groundwater and constructional materials (bricks, mortar, wood, out of service  waterproofing layer and other) were made. Abundance and species of micromycetes, aerobic and anaerobic bacteria were established. Change in microorganisms number with depth of foundation soils of the buildings depending from redox conditions was found. Reducing conditions with ORP (Oxidation-Reduction Potential) 10.18720/CUBS.90.1 69 Crumbling building geological-engineering features of moraine soils hydrogeological conditions physical and mechanical properties microbiota swab test method metagenomic analysis biocorrosion contamination https://unistroy.spbstu.ru/article/2020.90.1/ 9001-(1).pdf
RAR RUS 9002-9002 0000-0003-0413-3946 Federal University of Technology Minna Auta Samuel Mahuta samuel.auta@futminna.edu.ng
Niger State, Nigeria
 0000-0002-8271-6314 Federal University of Technology Minna Kabiru Adebayo bayo997@gmail.com
Niger State, Nigeria
 Effect of Locust Bean Pod Epicarp Ash (Lbpea) on the Compressive Strength of Revibrated Concrete The effect of locust bean pod epicarp ash (LBPEA) on the compressive strength of re-vibrated concrete is presented. The LBPEA used was obtained by controlled incineration of locust bean pod epicarp in an enclosed furnace. The result of the chemical analysis carried out on the LBPEA showed that it is a very good pozzolana with its SiO2, Al2O3, and Fe2O3 content percentage summation at 77.81%. Using a concrete mix ratio of 1:2:4 and a water-binder ratio of 0.6, a total of 147 cubes were cast and cured for 7, 14 and 28 days: 21 for control (0% LBPEA + 100% OPC); and 21 cubes for each other different percentages (5%, 10%, 15%, 20%, 25%, and 30%) replacements of OPC. Each category of cubes was initially vibrated and then re-vibrated at an interval of 10 minutes up till 1 hour. Compressive strength of the concrete cubes were determined at 7, 14 and 28 days curing age. The compressive strength increased gradually with curing age and a maximum compressive strength of 28.44 N/mm2 at 60 minutes revibration was obtained at 28 days for 5% of LBPEA. At 14 days curing, a maximum compressive strength of 24.76 N/mm2 at 60 minutes revibration was obtained for 0% of LBPEA. At 7 days curing, a maximum compressive strength of 25.29 N/mm2 at 60 minutes revibration was obtained for 0% of LBPEA. This suggests and is therefore recommended that a 5% replacement of OPC with LBPEA can be adopted for structural concrete production. 10.18720/CUBS.90.2 69 Locust bean pod epicarp ash Pozzolana Revibrated Concrete Compressive strength https://unistroy.spbstu.ru/article/2020.90.2/ 9002(1).pdf
RAR RUS 9003-9003 57193744331 0000-0001-7296-8158 Riga Technical University Buka-Vaivade Karina karina.buka.vaivade@gmail.com
Riga, Latvia
 H-9967-2013 16412815600 0000-0002-8588-3871 National Research University Moscow Power Engineering Institute Kirsanov Mikhail Nikolaevich mpei2004@yandex.ru
Moscow, Russian Federation
 6508223358 0000-0002-1843-3061 Riga Technical University Serdjuks Dmitrijs Dmitrijs.Serdjuks@rtu.lv
Riga, Latvia
 Analytical Expression of the Dependence of the Multi-lattice Truss Deflection on the Number of Panels The object of research is a flat statically determinate trapezoidal truss with a rectilinear lower chord and four supports, one of which is a pinned, and three are roller. The purpose of this work is to analyze the dependence of the deflection of the truss and the shift of the movable support on the size, load, and number of panels. The load concentrated in the middle of the span, the load uniformly distributed over the nodes of the upper or lower belt are considered. Method. The initial forces in the elements are determined in analytical form by method of joints in the Maple computer mathematics system. The dependence of the truss performance characteristics on the number of panels is derived by induction based on analytical calculations of the sequence of trusses with different numbers of panels. External static uncertainty is revealed by adding five reactions of supports to the number of unknown components of the equilibrium system of the structure. The deflection of the truss and the displacement of the support are based on the Maxwell-Mohr formula. Results. By solving a number of problems for trusses with a different number of panels, it is found that for trusses whose number of panels is a multiple of three, the determinant of the system of equilibrium equations of nodes turns to zero, which corresponds to the instantaneous kinematic variability of the truss. The corresponding scheme of possible node speeds was found. For kinematically unchangeable trusses, formulas for deflection depending on the number of panels are obtained. The coefficients in the formula are polynomial type. The solution graphs show an abrupt increase in deflection as the number of panels increases. 10.18720/CUBS.90.3 69 Truss Maple Deflection Symbolic solution induction https://unistroy.spbstu.ru/article/2020.90.3/ 9003(1).pdf
RAR RUS 9004-9004 B-4397-2014 56826013600 0000-0003-1071-427X Peter the Great St. Petersburg Polytechnic University Gravit Marina Viktorovna marina.gravit@mail.ru
St. Petersburg, Russian Federation
 0000-0003-0239-638X Riga Technical University Nazarov Mikhail Aleksandrovich mikenazarow95@gmail.com
Riga, Latvia
 0000-0002-7542-8533 State Fire Academy of Emercom of Russia Ivanov Vladimir Nikolaevich v.n.ivanov.pbs@ya.ru
Moscow, Russian Federation
 57197818952 0000-0002-9822-3637 Technische Universitat Graz Dmitriev Ivan Igorevich i.i.dmitriev@yandex.ru
Graz, Austria
 Fire resistance of monolithic reinforced concrete structures of the tall residential building with core structural system The key requirements of building codes for the bearing structures fire safety of high-rise buildings were identified. Heat-transfer and structural calculations were carried out for reinforced concrete monolithic pylon and floor slab of the building. Three different fire curves were implemented – the standard one and two real ones. It was established that for high-rise residential buildings a fire resistance limits of its structures should be determined based on the modern data about a fire load in the living units. This will lead to more cost-efficient building practice. 10.18720/CUBS.90.4 69 High-rise residential building Fire resistance Fire load Thermal regime Required fire resistance limits https://unistroy.spbstu.ru/article/2020.90.4/ 9004(1).pdf
RAR RUS 9005-9005 6506150284 0000-0003-1139-3164 Moscow State University of Civil Engineering Sainov Mikhail Petrovich mp_sainov@mail.ru
Moscow, Russian Federation
 Impact of concrete hardness of rockfill dam seepage-control face on its stress-strain state Introduction. It is known that at durable loads accommodation the concrete deformation modulus becomes 2÷3 times as less due to creep. The study fulfilled by the author permitted assessing the impact of stress relaxation in concrete of rockfill dam seepage-control face on its stress-strain state (SSS). Materials and methods. SSS was studied with the aid of numerical modeling by the finite element method. There was considered a 100 m high dam. Calculations were conducted for a wide range of variations of rockfill linear deformation values (from 60 to 480 МPа) and two values of its Poisson’s ratio (0.2 and 0.3). Various alternatives of under-face zone structural designs were considered. Modeling was made of shear characteristics decrease in the contact between the face and concrete bedding due to the arrangement of a bitumen mastic layer. Results. It was established that concrete linear deformation value Eb differently affects bending moments and longitudinal forces in the face. Decrease of Eb predominantly decreases bending moments from the face cross bending deformations but has a small impact on the longitudinal forces in it and bending moments from longitudinal bending deformations. Bending moments of cross bending are nearly in direct proportion with value Eb. Conclusions. The processes of creep and stress relaxation in concrete has a favorable effect on the face crack resistance because they decrease stresses in concrete. However, the value of stresses in the face concrete is not in direct proportion with concrete linear deformation modulus value Eb. It was established that the decrease of Eb by 60% decreases tensile stresses in the face concrete by approximately 30%. To decrease the risk of cracking in the face the quick reservoir impoundment is not recommended. In the analysis of concrete face rockfill dam structural design it is quite justified to analyze SSS at modulus Eb corresponding to its initial value without consideration of concrete creep because this case is more dangerous. 10.18720/CUBS.90.5 69 Concrete faced rockfill dam Stress-strain state Stress relaxation Strength Bending moment Longitudinal force Concrete deformation modulus Longitudinal bending https://unistroy.spbstu.ru/article/2020.90.5/ 9005(1).pdf
RAR RUS 9006-9006 57195684636 0000-0001-8800-2657 Voronezh State Technical University Slavcheva Galina Stanislavovna gslavcheva@yandex.ru
Voronezh, Russian Federation
 0000-0003-0032-7989 Voronezh State Technical University Kotova Kristina Sergeevna kottova-k@yandex.ru
Voronezh, Russian Federation
 Bending resistance of foam concrete beams reinforced with composite fittings The possibility of using glass composite fittings in bent elements made of foam concrete to determine the rational practical foam concrete application and options for their reinforcement in building structure has paper considered. Single beams, made of cement foam concrete and reinforced with various reinforcement frames of glass composite fittings, were investigated as flexural elements. Beams reinforced with welded frames are accepted as base comparison. The beam tests were carried out according to regulatory requirements with registration of load values and deformations and deflections during the test. Beam deflections were measured until the beam carrying capacity was exhausted. As a result, the ultimate load values and deflections of foam concrete beams were determined. According to the test results, the nature of the destruction of beams reinforced by various reinforcement frames and diagrams of deflection dependency on the bending moments are presented. It has been established that the values of beams deflections reinforced with glass composite fittings are 8.5% higher than the values of beams deflections reinforced with welded frames. However, the deflection values of beams with standard framework from glass composite fittings do not exceed the maximum permissible deflection value of 9,75 mm. Therefore, the glass composite fittings can be adopted to reinforce the foam concrete flexural elements. 10.18720/CUBS.90.6 69 Foam concrete Beams Composite fittings Joint work Deflection Bending resistance https://unistroy.spbstu.ru/article/2020.90.6/ 9006.pdf
RAR RUS 9007-9007 57208104857 0000-0003-3313-7305 Kazan State University of Architecture and Engineering Zamaliev Farit Sakhapovich zamaliev49@mail.ru
Kazan, Russian Federation
 INFRA FER Fekir Kahina FekirKahina@gmail.com
Rouiba, Algerie
 Kazan State University of Architecture and Engineering Bikkinin Emil Gatovich bekkan91@gmail.com
Kazan, Russian Federation
 Self-stressed and prestressed steel-reinforced concrete beams A method and analysis of the internal stress-strain state of the bent composite section are presented.  The methods of self-stressing of steel-concrete construction elements are given. The method of self-stressing of the steel-concrete bending elements, which was not previously known, through the use of shrinkage forces of concrete in composite structures is given. The results of the numerical investigation of self-stressing and prestressing steel-concrete beams using computer programs are described. The prestressing forces were transmitted to the end stops due to the steel rigid ribs of the composite structure. Prototypes were made for the full-scale test and tested based on the results of numerical studies. The results of full-scale tests are presented and comparisons with the results of numerical studies are given. 10.18720/CUBS.90.7 69 Steel – concrete construction Prestress Self-stress Full-scale experiment Stresses Deflections https://unistroy.spbstu.ru/article/2020.90.7/ 9007(1).pdf