33407 2304-6295 Construction of Unique Buildings and Structures 5 103 2022 1-60
RAR RUS 10301-10301 57210972600 0000-0001-6472-9413 Kazan State University of Architecture and Engineering (KSUAE) Shmelev Gennady Nikolaevich gn.shmelev@mail.ru
Russian Federation, Tatarstan republic, Kazan, Zelenaya Str., 1
 57218824920 0000-0002-7883-1264 Kazan State University of Architecture and Engineering (KSUAE) Eremeev Daniil Valerievich danil-123456@inbox.ru
Russian Federation, Tatarstan republic, Kazan, Zelenaya Str., 1
 57218829319 0000-0002-2506-9042 JSC Spetsremproekt Eremeev Valery Pavlovich ere1953@inbox.ru
Russian Federation, Tatarstan republic, Kazan, Zaslonova Str., 5
 6507946547 0000-0002-8202-5732 Kazan State University of Architecture and Engineering (KSUAE) Eremeev Pavel Valerievich pavil-66@inbox.ru
Russian Federation, Tatarstan republic, Kazan, Zelenaya Str., 1
 Oscillation Suppression of Pedestrian Overpasses The objects of research are pedestrian overpasses. The purpose of this work is to analyze the issues of suppression of such overpasses from oscillation caused by movement of trains and crowds. There are many ways to suppress oscillation, including increasing the longitudinal stiffness, introducing an additional connection, and using elastic or viscoelastic dampers. Problems arise when determining the need for measures to suppress oscillation in particular cases. Method.  The need for suppression is determined for a pedestrian overpass with a span of 44.6 m, which is tested to determine the natural vibration frequency and the logarithmic decrement of attenuation. A comparative analysis of different solutions for oscillation suppression is carried out. A computational model of a pedestrian overpass based on the finite element method is developed. The dynamic impact from the crowd is set as a time – force function, based on the condition that 12.5% of pedestrians move synchronously. The possibility of simplifying the design scheme by replacing the base and supports with boundary conditions is determined. The dynamic influence of a train on a pedestrian overpass is studied. The load from the train is set by the time-force function and the displacement equation. Three different cases of loading from the train are studied, varying on weight and the number of wheels. Results. A comparative analysis of oscillation damping measures shows that the most effective solution is to introduce a viscoelastic damper. This way, it is possible to reduce the mean square acceleration of oscillations by 8.4 times to the required values, with the lowest material consumption. 10.4123/CUBS.103.1 69 Pedestrian overpasses; Dynamics; Oscillation; Suppression; Dampers; Construction https://unistroy.spbstu.ru/article/2022.103.1/ 10301.pdf
RAR RUS 10302-10302 E-6426-2019 56434340300 0000-0002-5694-1737 Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russian Federation Usanova Kseniia Iurevna plml@mail.ru
St. Petersburg, Russian Federation
 AAH-2547-2019 7801686579 0000-0001-7011-8213 Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russian Federation Barabanshchikov Iurii Germanovich ugb@mail.ru
St. Petersburg, Russian Federation
 Provcement-Vector JSC, St. Petersburg, Russian Federation Uhanov Aleksandr Valerievich Provcement-Vector JSC, St. Petersburg, Russian Federation Kalachev Andrej Irineevich Neutralization of high-calcium fly ash expansion The object of research is fly ash from Berezovskaya GRES. A feature of this fly ash is the high content of calcium oxide in the free state, the hydration of which occurs at a later age, when the bulk of the material has already hardened. The transition from CaO to Ca(OH)2 is accompanied by an increase in volume, which in turn can lead to the cracks in the material. The purpose of the work is to study the possibility of neutralizing the high-calcium fly ash expansion. Method. Tests for the expansion of fly ash paste with various additives in Le Chatelier mold, X-ray diffraction (XRF) and differential thermal (DTA) analyzes of the samples were carried out, their compressive strength was determined. Results. The Le Chatelier molds test showed that microsilica and silicic acid have the greatest influence on the fly ash expansion. When the microsilica content is about 40% by weight of fly ash, there is no expansion of the paste. The compressive strength of samples from the 1:5 fly ash-sand mortar at the age of 28 days was 1.47 MPa. Based on the results of X-ray diffraction analysis and DTA, it was found that in the absence of microsilica, free lime in the fly ash is completely hydrated in 11 days, giving the highest degree of expansion. In the presence of microsilica, the expansion is reduced, however, unslaked free lime remains in the system. 10.4123/CUBS.103.2 69 Concretes Binder High-calcium fly-ash Aggregate Strength Expansion Microsilica Silica fume https://unistroy.spbstu.ru/article/2022.103.2/ 10302.pdf
RAR RUS 10303-10303 ABE-1858-2021 57208300172 0000-0002-8396-4870 Peter the Great St. Petersburg Polytechnic University Kotliarskaia (Vasileva) Irina Leonidovna iravassilek@mail.ru
St. Petersburg, Russian Federation
 O-6995-2019 6508103761 0000-0002-1196-8004 Peter the Great St. Petersburg Polytechnic University Vatin Nikolai Ivanovich vatin@mail.ru
St. Petersburg, Russian Federation
 G-2929-2018 56227381900 0000-0003-2673-4566 Peter the Great St. Petersburg Polytechnic University Sergeeva (Nemova) Darya Viktorovna darya0690@mail.ru
St. Petersburg, Russian Federation
 Thermal conductivity of aerogel thermal insulation under stationary thermal conditions The object of research is the thermal conductivity of aerogel thermal insulation under stationary thermal conditions. Method. The study uses an experimental research method. Results. The actual thermal conductivity coefficient of the innovative aerogel nanomaterial in the form of a roll insulation was determined. It is equal to 0.0227 W/(m*K). This value is within the margin of error. Among the thermal insulation materials in the construction market, the material Alison Aerogel Blanket DRT06-Z stands out with the lowest coefficient of thermal conductivity. 10.4123/CUBS.103.3 69 Aerogel Thermal conductivity Thermal insulation Nanomaterial Energy efficiency https://unistroy.spbstu.ru/article/2022.103.3/ 10303.pdf
RAR RUS 10304-10304 AAE-3259-2020 56296687300 0000-0002-2299-3096 Peter the Great St. Petersburg Polytechnic University Rybakov Vladimir Alexandrovich fishermanoff@mail.ru
St. Petersburg, Russian Federation
 Conjugate Approximation of Thin-Walled Rods Internal Forces Functions in Bending Torsion The goal of the work is to increase the convergence rate of bending torsion internal forces (bimoment, moment of warping torsion, moment of pure torsion) in finite elements in the calculation of thin-walled rods using V.I. Slivker's semi-shear theory. The object of research is the finite elements (FE) proposed earlier by the author of the article as part of the theory of V.I.Sliver's semi-shear theory, which differs from other FE by the approximation method of unknown functions: 3-nodal finite element having 5 degrees of freedom with square-law approximation of torsional angle function and linear approximation of warping function and 3-nodal finite element having 6 degrees of freedom with square-law approximation of torsional angle and warping functions. The subject of research is the convergence of internal forces in thin-walled rods, determined using the conjugate approximation method. Method of research is mathematical modeling of parameters (stiffness matrix, load column) and determination of the unknowns of two systems equations: of the FE-method and of the conjugate approximation method. Results. The formulas of the conjugate approximations method of are proposed in 2 variants: linear and quadratic conjugate approximations. On particular cases of two-sided fixed and cantilever beams, it is shown that when calculating open-type profiles, an acceptable 5% engineering error is provided by a linear conjugate approximation of the bimoment. For closed profiles, due to the special pattern of the bimoment distribution near the fixed supports, the linear conjugate approximation cannot provide engineering accuracy: it is necessary to use the deviding of the rod into 32 finite elements or more and use the quadratic conjugate approximation to refine the bimoment values ​​on fixed supports. 10.4123/CUBS.103.4 69 Lightweight gauge steel structures Bending torsion Thin-walled structures Thin-walled rods Bimoment Warping Moment of warping torsion Moment of pure torsion https://unistroy.spbstu.ru/article/2022.103.4/ 10304.pdf