69439 2658-5553 24 4 24 2022 1-60

RAR RUS 2401-2401 E-6426-2019 56434340300 0000-0002-5694-1737 Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russian Federation Usanova Kseniia Yuryevna plml@mail.ru

St. Petersburg, Russian Federation

Thermal performance of external wall panel made of cold-bonded fly ash aggregate concrete The object of research is an external wall panel made of cold-bonded fly ash aggregate concrete. The purpose of this work is to study thermal performance of the external wall panel made of cold-bonded fly ash aggregate based on fly ash from Novosibirskaya GRES Thermal Power Plant. Method. The panel under study consists of three layers: an inner layer of concrete with cold-bonded fly ash aggregate, an intermediate layer of extruded polystyrene, and an outer layer of heavy concrete. For the thermotechnical calculation of the external wall panel, the thermal conductivity coefficient of cold-bonded fly ash aggregate concrete was experimentally determined using the thermal conductivity meter ITS-1 "150". Specimens were made in the form of plates with dimensions of 150x150x30 mm. Demoulding was carried out on the second day after the specimens were made. Subsequently, the samples were stored under normal conditions at a temperature of 20 ± 2 °C and a relative air humidity of at least 60%. After that, the thickness of the insulation was calculated for the panel under study. The thermal performance of the studied external wall panel was compared with a typical three-layer reinforced concrete panel. Results. The thermal conductivity coefficient of cold-bonded fly ash aggregate concrete was experimentally determined, which amounted to 0.94 W/(m·°C). It is shown that in terms of thermal performance, the external wall panel made of cold-bonded fly ash aggregate concrete is not inferior to the well-known three-layer reinforced concrete wall panel. With the same thermal characteristics of the studied external wall panel, a heat-insulating layer of extruded polystyrene of a smaller thickness is required - 90 mm instead of 100 mm for a three-layer reinforced concrete panel. 10.57728/ALF.24.1 69 Concrete Fly ash Wall panel Thermal conductivity Aggregate R-value Building materials Construction https://alfabuild.spbstu.ru/article/2022.24.1/ 2401.pdf

REV RUS 2402-2402 ABE-1858-2021 57208300172 0000-0003-0031-7270 Peter the Great St. Petersburg Polytechnic University Kotliarskaia Irina Leonidovna iravassilek@mail.ru

St. Petersburg, Russian Federation

ABD-9922-2021 0000-0002-9330-2221 Peter the Great St.Petersburg Polytechnic University Iakovlev Nikita Artemovich nik_yakovlev@list.ru

Russia, 195251, St.Petersburg, Polytechnicheskaya, 29

O-6995-2019 6508103761 0000-0002-1196-8004 Peter the Great St. Petersburg Polytechnic University Vatin Nikolai Ivanovich vatin@mail.ru

Saint-Petersburg, Russian Federation

56227381900 0000-0003-2673-4566 Peter the Great St. Petersburg Polytechnic University Nemova Darya Viktorovna nemova_dv@spbstu.ru

St. Petersburg, Russian Federation

Modular energy-efficient enclosing structures with the aerogel thermal insulation. A review The course to modular construction is becoming more and more popular. New developments in this field are constantly appearing. The object of the study are modular energy-efficient building enclosure structures with the aerogel-based thermal insulation materials. The analysis of available developments and technological solutions in the field of modular facade systems. The features of aerogel and composite materials on its basis were considered. Due to numerous studies and developments, these materials are becoming more accessible and applicable in different areas, including the construction industry. As a result of the analysis, it was found that the construction of modular structures is perspective. Modular building envelopes in combination with aerogel-based thermal insulation materials help to reduce the energy consumption of buildings and structures, as well as help to reduce carbon dioxide emissions. 10.57728/ALF.24.2 69 Module Modular building Modular facade Aerogel insulation Energy efficiency Enclosing structures https://alfabuild.spbstu.ru/article/2022.24.2/ 2402-2.pdf

RAR RUS 2403-2403 AAE-3259-2020 56296687300 0000-0002-2299-3096 Rybakov Vladimir Alexandrovich The V.I. Slivker's semi-shear theory finite elements research for calculation of thin-walled closed profile rods The object of research is the finite element (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 6 degrees of freedom square-law approximation of torsional angle functions and warping functions. The subject of research is the convergence for the considered FE of displacements functions of both types (torsional angle and warping) and internal forces (bimoment, sectorial torsion moment and pure torsion moment) that occur during bending torsion and are the important components for calculating stresses according to the standarts. Method of research is mathematical modeling of parameters (stiffness matrix, load column) and determination of the unknowns of equations of the FE-method. Results. The test problems of thin–walled rods bending torsion for a number of boundary conditions are solved on the example of a closed profile; the main advantage of V.I.Slivker's theory (universality for open and closed profiles) and, as a consequence, the advantage of the previously proposed finite elements are demonstrated on concrete examples. It is shown that the FE with quadratic approximation has the convergence acceptable for engineering calculations for rods of not only open, but also closed profiles. Also obtained in the V.I.Slivker's semi-shear theory the expression for the influence parameter of thin-walled rectangular  profiles shape is creamed and the spectrum of its values is investigated. 10.57728/ALF.24.3 69 Warping Shear deformation Bimoment Stiffness matrix Thin-walled closed profile Thin-walled closed rods Lightweight gauge steel structures bending torsion The influence parameter of thin-walled profile shape Semi-shear theory https://alfabuild.spbstu.ru/article/2022.24.3/ 2403_1.pdf