TECHNOLOGY OF ERECTION OF PRECAST FRAME BUILDINGS AT NEGATIVE TEMPERATURES

Vestnik MGSU 4/2012
  • Afanas'ev Aleksandr Alekseevich - Moscow State University of Civil Engineering (MSUCE) Professor, Doctor of Technical Sciences, +7 (495) 287-49-14, ext. 31-25, Moscow State University of Civil Engineering (MSUCE), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation.

Pages 175 - 180

In the article, the author describes the technological peculiarities of erection of frame buildings at negative temperatures. The author also demonstrates structural and technological peculiarities of prefabricated frame elements. The author also speaks about the technology of prefabricated production of stacked columns, pre-stressed girders, beams and hollow core slabs.
It is proven that the frame system is applicable for the construction of industrial, residential and office buildings that may have different numbers of storeys and that are flexible in terms of design concepts. Besides, the author describes the technological peculiarities of the assembly of structural elements, their temporary and permanent fixing.
The author also provides basic requirements applicable to the technology of grouting of column-to-girder joints and hollow slabs designated for a cased frame. The article also contains an analytical solution of the heat conductivity equation that describes the period of heating of connected elements. The solution makes it possible to use numerical methods to identify the depth of heating of girders and columns, depending on the ambient temperature and the duration of exposure to the heat.
The author has also analyzed the technology of grouting of precast structure joints at negative temperatures in the event of pre-heating of structural elements to be connected and the heating of the concrete mix with heating wires. The author has identified the range of rational heating modes for structural joints on the basis of the parameters of negative temperatures.

DOI: 10.22227/1997-0935.2012.4.175 - 180

References
  1. Schembakov V.G. Sborno-monolitnoe karkasnoe stroitel'stvo [Precast Monolithic Frame Construction]. Cheboksary, 2004. 96 p.
  2. Afanas'ev A.A., Minakov Yu.A. Otsenka teplovykh poley pri uskorennykh metodakh tverdeniya betona v monolitnom domostroenii [Assessment of Thermal Fields as part of Methods of Accelerated Hardening of Concrete in Monolithic House Building]. Sbornik “Teoreticheskie osnovy stroitel'stva” [Collected Works. Theoretical Foundations of Construction]. Moscow, 1999, pp. 16—22.
  3. Tikhonov A.N., Samarskiy A.A. Uravneniya matematicheskoy fiziki [Equations of Mathematical Physics]. Moscow, Nauka Publ., 1966, 724 p.
  4. Mironov S.A. Teoriya i metody zimnego betonirovaniya [Theory and Methods of Winter-time Concreting]. Moscow, S.K. Publ., 1975, 700 p.
  5. Afanas'ev A.A., Selischev K.S. Tekhnologii omonolichivaniya stykov pri vozvedenii karkasnykh zdaniy [Technology of Grouting of Joints in Construction of Frame Buildings]. Vestnik MGSU [Proceedings of Moscow State University of Civil Engineering]. 2010, no. 4, pp. 34—38.
  6. Gmyrya A.I., Korobkov S.V. Tekhnologiya betonnykh rabot v zimnikh usloviyakh [Technology of Concrete Works in Winter Conditions]. Tomsk, TGASU [Tomsk State University of Architecture and Civil Engineering], 2011, 411 p.

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Analysis of heat losses in stoves. The real efficiency of the furnace

Vestnik MGSU 11/2018 Volume 13
  • Shevyakov Vladimir V. - Candidate of Technical Sciences, independent researcher; ORCID 0000-0001-5946-2742..

Pages 1296-1304

Introduction. An approach to the development of recommendations on the choice of operating modes of the furnace and of its design parameters is presented. Efficiency of a household stove is a rather broad concept by which the uniform heating of stove surfaces and heat transfer over time, etc. are understood. The ability of the stove to receive heat from burning wood and transfer heat to the room with minimal losses is the technical characteristics, which we will consider. The operation of any furnace is cyclic. Each cycle consists of two parts: the accumulation of heat (the mode of the furnace, the combustion of wood) and the heat transfer to a heated room (the mode of heat release). The furnace furnace mode is characterized by the efficiency of the furnace. Not all the heat left in the furnace is transferred to the room. Part of the heat goes into the foundation and through the valves in the pipe. The estimation of heat losses and the amount of carbon monoxide in a household oven, recommendations for their reduction are given. Materials and methods. A detailed analysis and assessment of heat losses, an estimate of the amount of carbon monoxide in a household oven, and the development of recommendations for their reduction are given. Results. The results of the study and analysis are used to develop ecommendations on the choice of operating modes of the furnace and the choice of its design parameters. Conclusions. The results of the work can be recommended in the development of domestic stoves.

DOI: 10.22227/1997-0935.2018.11.1296-1304

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Thermal regime of enclosing structures in high-rise buildings

Vestnik MGSU 8/2018 Volume 13
  • Musorina Tatyana A. - Peter the Great St. Petersburg Polytechnic University (SPbPU) postgraduate student, Hydraulics and Strength Department, Peter the Great St. Petersburg Polytechnic University (SPbPU), 29 Politechnicheskaya s., St. Petersburg, 195251, Russian Federation.
  • Gamayunova Ol’ga S. - Peter the Great St. Petersburg Polytechnic University (SPbPU) Senior lecturer, Department of Construction of Unique Buildings and Structures, Peter the Great St. Petersburg Polytechnic University (SPbPU), 29 Politechnicheskaya s., St. Petersburg, 195251, Russian Federation.
  • Petrichenko Mikhail R. - Peter the Great St. Petersburg Polytechnic University (SPbPU) Doctor of Technical Sciences, Professor, Head of the Hydraulics and Strength Department, Peter the Great St. Petersburg Polytechnic University (SPbPU), 29 Politechnicheskaya s., St. Petersburg, 195251, Russian Federation.

Pages 935-943

Subject of research: the main heat loss occurs through the building fence. In the paper, the object of research is enclosing structures with different thermal conductivity. The problem of moisture accumulation in the wall is quite relevant. One of the main problems in construction is saving on building materials and improper design of building envelope. This in turn leads to a violation of the heat and humidity regime in the wall. This paper presents one of the methods to address this issue. Purpose: description of heat and humidity conditions in the wall fence of high-rise buildings. It is also necessary to analyze the relationship between the thermophysical characteristics. Materials and methods: the temperature distribution in the layers will be analyzed on the basis of the structure consisting of 10 layers; the layer thickness is 0.05 m. Materials with different thermal conductivity were used. Each subsequent layer differed in thermal conductivity from the previous one by 0.01. Next, these layers are mixed. The calculation of the humidity regime includes finding the temperature distribution along the thickness of the fence at a given temperature of the outside air. The quality factor of the temperature distribution is the maximum average temperature. This research are conducted in the field of energy efficiency. Results: the higher the average wall temperature, the lower the air temperature differs from the wall temperature. In addition, the higher the average temperature of the wall, the drier the surface inside the wall. However, moisture accumulates on the surface inside the room. The working capacity of multilayer enclosing structures is determined by the temperature distribution and distribution of moisture in the layers. Conclusions: moisture movement through the fence is due to the difference in the partial pressure of water vapor contained in the indoor and outdoor air. A layer with minimal thermal conductivity should be located on the outer surface of the wall in a multi-storey building. The maximum change in the amplitude of temperature fluctuations is observed in the layer adjacent to the surface by periodic thermal effects. It is also taken into account that the process of heat absorption has a great influence on the temperature change in the thickness of the wall fence to the greatest extent within the layer of sharp fluctuations (outer layer). The Central part of the wall (bearing layer) will be the driest. These calculations are satisfied with the design of the ventilated facade.

DOI: 10.22227/1997-0935.2018.8.935-943

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