33407
2304-6295
Construction of Unique Buildings and Structures
4
102
2022
1-60
RAR
RUS
10201-10201
0000-0002-0570-0298
Samoylenko
Mikhail Evgenyevich
Donetsk Promstroyniiproekt
m-samoylenko@mail.ru
Donetsk, Ukraine
0000-0002-6593-0298
Butova
Аlla Pavlovna
Donbas National Academy of Civil Engineering and Architecture
alla-butova@rambler.ru
Makeyevka, Ukraine
Aerodynamic external pressure coefficients for rectangular buildings
The object of the research is rectangular civil buildings located in dense urban areas of various configurations. The purpose of the work is to clarify the aerodynamic coefficients of external pressure on the surface of the facades of the building, depending on the type of urban areas and the direction of the wind flow. Method is an experimental research of wind flow around building models in a wind tunnel of recirculation type with imitation of the atmospheric boundary layer. The experiment provides for the study of various types of urban construction of building that are most often encountered in the design of microdistricts. Results. The distribution of wind pressure along the plane of the facades is very heterogeneous and depends on the type of urban construction of building, the direction of the wind flow, the height of the obstruction and the distance to them. It is impossible to offer a simple universal model for determining aerodynamic coefficients that takes into account all possible options for the interaction of a building with a wind flow. The simple schemes of aerodynamic coefficients proposed today in building codes are the only acceptable way to determine wind loads. Regulatory aerodynamic coefficients for the windward (ce=0.8) and leeward (ce=-0.5) facades of rectangular buildings ensure the collection of the wind load «in reserve» for almost any type of urban areas and obstruction heights. The experimental data for zones A, B and C of the main facades differ significantly from those indicated in Russian building regulations SP 20.13330.2016. The peak values of the aerodynamic coefficients cp,- for zone A are significantly less than those regulated by SP 20.13330.2016. These coefficients require clarification.
.
10.4123/CUBS.102.1
69
Wind load
Aerodynamic coefficient
Wind flow
Wind tunnel
Building type
Building model
Urban construction of building
Urban areas
https://unistroy.spbstu.ru/article/2022.103.1/
RAR
RUS
10202-10202
0000-0002-6649-8855
Kondrashov
Aleksey Vladimirovich
Peter the Great St.Petersburg Polytechnic University
kondrashov.av@edu.spbstu.ru
St.Petersburg, Russian Federation
0000-0003-1863-4186
Trinchenko
Aleksey Alexandrovich
Peter the Great St.Petersburg Polytechnic University
trinchenko@spbstu.ru
St.Petersburg, Russian Federation;
Reducing utility bills through the introduction of energy efficient systems
The object of the study is an improved system for the partial recovery of the condensation heat of refrigeration machines, its development, implementation and study of operational performance, which increases the share of waste heat in the air heating system in order to increase their energy efficiency and optimize operating costs. The purpose of this work is to analyze the costs of using heat to heat the coolant in the air heating system from the heat supply organization, with the costs in case of heating the coolant in the condensation heat recovery system. Method. To analyze the calculated and actual values, the development and implementation of a research stand based on an ultrasonic flow switch and a heat meter was carried out, which made it possible to evaluate the economic effect of the implementation of the proposed solutions. Results. With regard to the air heating system of buildings with artificial freezing of the ice surface, the economic effect in the form of a reduction in utility bills for heating is 2.46 million rubles per year, while reducing the thermal pollution of the environment by at least 1.4 GW.
10.4123/CUBS.102.2
69
Energy efficiency
Heat recovery
Communal payments
Air heating
Thermal pollution
https://unistroy.spbstu.ru/article/2022.103.2/
RAR
RUS
10203-10203
G-1611-2018
56352359500
0000-0002-5156-7352
Korniyenko
Sergey Valeryevich
Volgograd State Technical University
svkorn2009@yandex.ru
Volgograd, Russian Federation
0000-0003-4888-7117
Dikareva
Ekaterina Aleksandrovna
Volgograd State Technical University
Ea.dikareva@gmail.com
Russia, 400005, Volgograd, pr. Lenina, 28
The sky visibility at shading by trees
The development of green infrastructure is an urgent task in developing an urban planning strategy to reduce the effect of an urban heat island and improve the urban ecosystem. The purpose of this study is to assess the visibility of the sky at shading by trees when solving the problems of predicting the formation of an urban heat island and developing recommendations for its mitigation. The object of research. Several species of trees were selected, the most common in greening in the hot climatic conditions: elm (Ulmus L.), oak (Quercus L., 1753), maple (Acer L., 1753) and poplar (Populus L., 1753). For each of these tree species, several samples required for data averaging were selected. A total of 27 samples were examined. Field studies were conducted in various months of the year (10.05.2021, 16.07.2021 and 03.10.2021). Method. A characteristic of sky visibility is sky visibility factor (SVF). Various approaches to determining the visibility of the sky are considered. A common limitation of computational methods is the ability to define SVF for relatively simple object configurations. Therefore, to find SVF complex heterogeneous systems, such as trees, we made direct measurements by photographing using a special fisheye lens and a smartphone. Data verification confirms the possibility of using this equipment for field studies. The method of black, white and gray pixels was used to process photo images, which allows you to increase the accuracy of the results. Results. Analysis of the results shows that the minimum SVF values for all tree species studied are observed in July. At this point in time, the tree crown is densest, limiting the visibility of most of the sky. The maximum effect of shading in summer is provided by oak (SVF = 22.9%), minimal – by elm (SVF = 30.4%). It is shown that trees with denser krone block long-wave radiation streams day at night that leads to growth of the urban heat island. Comparing the received results, it is possible to note that the minimum mitigation (8.0 K) gives an elm; maximum mitigation (8.8 K) gives an oak. Therefore, for protection against solar radiation in the afternoon it is better to use an oak, and for mitigation of the urban heat island it is better to use an elm at night. Thus, the method allows choosing a species of the tree providing the required shading and effect of mitigation of the urban heat island. Further researches will be connected with specification of mathematical model of the urban heat island for assessment of a microclimate of the urbanized territories during the hot period.
10.4123/CUBS.102.3
69
Architecture
Urban planning
Construction
Environment
Megalopolis
Energy saving
Energy efficiency
Cooling
Passive strategies
Sky View Factor
Urban Heat Island
Fish eye
Climate
Thermal comfort
Green construction
HVAC
Trees
Green infras
https://unistroy.spbstu.ru/article/2022.103.3/
10203.pdf
RAR
RUS
10204-10204
H-9967-2013
16412815600
0000-0002-8588-3871
Kirsanov
Mikhail Nikolaevich
National Research University Moscow Power Engineering Institute
mpei2004@yandex.ru
Moscow, Russian Federation
Deformations of a planar multi-span arch truss: analytical solutions
The object of research. A scheme of a statically determinable indefinite truss with arched spans is proposed. The upper belt of the structure is rectilinear. The side supports of the truss are fixed hinges, the intermediate ones are movable. The truss is subjected to a vertical load, evenly distributed over all nodes of the upper chord of the truss or concentrated in the middle of the middle span. The derivation of formulas for calculating the dependence of the deflection of the middle span on the load, dimensions and number of spans is given. Analytical expressions are derived for the forces in the critical elements for an arbitrary number of spans of the structure. Method. The calculation of the forces in the elements and the reaction of supports of an externally statically indeterminate structure is carried out by cutting out all nodes from the solution of a joint system of equilibrium equations for nodes. The expression for the deflection is in symbolic form according to the Maxwell – Mohr formula. The generalization of a series of solutions to an arbitrary number of spans is carried out by induction. Results. The dependences found for the forces in the rods and deflections have a compact form and allow one to give simple estimates of the solutions. It is noted that the forces in all the rods of the upper chord, except for the side ones, in the case of a uniform load are equal to zero for arbitrary truss sizes and the number of spans. The dependence of the deflection on the number of spans has a jumplike character. All necessary transformations and analysis of solutions are performed in the Maple symbolic mathematics system. Linear asymptotics of the solutions for the deflection are derived.
10.4123/CUBS.102.4
69
Truss
Maple
Maxwell – Mohr formula
Deflection
Exact solution
Arch
Number of spans
https://unistroy.spbstu.ru/article/2022.103.4/
10204.pdf
RAR
RUS
10205-10205
56166386300
0000-0003-4894-9023
Perminov
Nikolai Alekseevich
Emperor Alexander I St. Petersburg State Transport University
perminov-n@mail.ru
Saint Petersburg, Russian Federation
Monitoring and protection of sewer tunnels in difficult ground conditions with increasing anthropogenic impact
The object of research. Long-term operation of sewer tunnels in difficult engineering and geological conditions creates the danger of violating their structural safety. A long-term study of the changes’ dynamics in the technical state of the tunnels made it possible to establish the patterns of intense anthropogenic and dynamic influences on this process. Method. The developed discrete and continuous diagnostic models of the defects’ development in the tunnels’ structures make it possible to identify potentially hazardous areas subject to the manifestation of critical failures and methods of their localization. On the basis of numerical modeling, the boundaries of defect-free joint operation of the system “source of impact – geo-mass - sewer tunnel” have been determined. Results. With increasing external anthropogenic and dynamic impacts, modeling zones of urban areas with potentially dangerous sections of underground sewage facilities is the basis for the development of regulatory documents on monitoring methods and safe development geotechnical infrastructure.
10.4123/CUBS.102.5
69
Monitoring
Tunnel
Weak soils
Anthropogenic impacts
Protection
https://unistroy.spbstu.ru/article/2022.103.5/