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17Central Asian Research Journal For Interdisciplinary Studies (CARJIS)
ISSN (online): 2181-2454
Volume 2 | Issue 5 | May, 2022 | SJIF: 5,965 | UIF: 7,6 | ISRA: JIF 1.947 | Google Scholar |
www.carjis.org DOI: 10.24412/2181-2454-2022-5-41-46
MODERN EXTERNAL WALL STRUCTURES FROM CELLULAR
CONCRETE AND LIGHT STEEL THIN-WALL STRUCTURES FOR
REINFORCED CONCRETE FRAME MULTISTORY BUILDINGS
Abbos Agzamovich Khodjaev
Doctor of Technical Sciences, Professor, Turin Polytechnic University in Tashkent
Ibrokhim Soibjonovich Karimjonov
Master student of Tashkent Institute of Architecture and Civil engineering
ibrokhim.k.323 @gmail .com
Abzalkhon Akmalovich Saidakromov
Tashkent Institute of Architecture and Civil engineering
ABSTRACT
The article is devoted to a review of publications on the topic of the use of foamed aerated gas-concrete blocks and frame-sheathing walls as external walls in multi-storey reinforced concrete frame buildings.
Thin-walled structures today have broad prospects for introduction into mass construction in Uzbekistan and abroad and can be used in the construction of several structures for various purposes. The rapid pace of scientific and technological progress, as well as the emerging trends towards the rationalization of design and installation work, assign lightweight steel thin-walled structures (LSTS) to one of the main roles in modern civil and industrial construction.
Keywords: Frame-sheathing wall (FSW), lightweight steel thin-walled structures (LSTS), aerated gas-concrete block, thermal profile, energy saving, ecology, thermal insulation, brick, aerated gas-concrete.
INTRODUCTION
Autoclaved aerated gas-concrete block masonry is used in the construction of external and internal enclosing wall structures of modern buildings, both high-rise apartment buildings and low-rise private ones. Foamed concretes have found wide application in various areas of modern construction, which is ensured by the specific features of the porous structure and, accordingly, the variety of functional purposes.
The construction of prefabricated, comfortable, environmentally friendly, and
Central Asian Research Journal For Interdisciplinary Studies (CARJIS)
ISSN (online): 2181-2454
Volume 2 | Issue 5 | May, 2022 | SJIF: 5,965 | UIF: 7,6 | ISRA: JIF 1.947 | Google Scholar |
www.carjis.org DOI: 10.24412/2181-2454-2022-5-41-46
energy-efficient housing is currently an important aspect of the development of housing construction throughout Uzbekistan. Especially, this task is critical in seismically active areas and in areas with a harsh climate. One of the options for solving this problem is the construction of buildings using frame-sheathing walls (FSW) from lightweight steel thin-walled structures (LSTS).
METHODOLOGY
The bearing capacity of foamed concretes, with their characteristics of low density, is sufficient for the manufacture of enclosing structures of walls and coverings of elements, ceilings, and load-bearing elements of low-rise construction.
High heat-shielding characteristics, fire resistance, heat capacity and moisture capacity determine the unique combination in one material of all those positive qualities that are individually inherent in traditional building materials.
Autoclaved aerated gas-concrete is one of the most popular wall materials currently used for outdoor enclosing. The main design solutions for external walls, like in Russia, which use aerated concrete block masonry, can be systematized as follows.
Single layer aerated concrete wall. Masonry performs a constructive and thermal insulation function. Exterior finish - primer, thin-layer plaster, painting. It is used in most cases on glazed balconies and loggias D350, 300 mm or D400, 375 mm.
Single layer aerated concrete wall with brick cladding. Facing layer - 120 mm, less often - 250 mm. The cladding layer either closes the ends of the floors or is laid out flush with them. Aerated concrete grades D400-D500 with 300-400 mm thickness.
Aerated concrete masonry with external insulation. For insulation, either a heat-insulating facade with a thin plaster layer, or a hinged facade system with a ventilated air gap is used. Aerated concrete mainly performs the function of a carrier base for insulation. Thickness - 200-250 mm. Mark on average density within D400-D600. The choice of a constructive solution also determines the set of problems that may arise at the stages of construction and operation of the facility[1].
For the application of technological solutions in the regulatory field of documents regulating construction in areas with a seismicity of 7, 8 and 9 points, the experience of using foamed concrete blocks in the design and construction of buildings in seismically hazardous areas by specialists of Baikal Aerated Concrete LLC and TsNIISK im. V.A. Kucherenko is summarized and systematized in the
Central Asian Research Journal For Interdisciplinary Studies (CARJIS)
ISSN (online): 2181-2454
Volume 2 | Issue 5 | May, 2022 | SJIF: 5,965 | UIF: 7,6 | ISRA: JIF 1.947 | Google Scholar |
www.carjis.org DOI: 10.24412/2181-2454-2022-5-41-46
Album of Technical Solutions ATP ErE 4.1-2015[2, 3].
Aerated gas-concrete refers to structural and heat-insulating building material.
Its use in construction allows:
- Significantly reduce the mass and thickness of the walls.
- Provide the necessary thermal performance of walls, ceilings, and coatings.
- By reducing the weight of the walls, to reduce the cost of building load bearing elements of the building and the construction of the foundation.
- Build walls of any geometry in plan.
- To reduce the cost of finishing interior and exterior walls due to the smoothness and uniformity of the block masonry surface.
Aerated gas-concrete products are widely used:
- In low-rise construction.
- In multi-storey buildings.
- In private housing construction.
- In the construction of social and cultural facilities.
- In the construction of industrial buildings and structures.
- In the construction of warehouse buildings.
- In the modernization and repair of buildings and premises.
- In interior design.
- At redevelopment of premises.
Autoclaved aerated gas-concrete blocks are designed for laying the outer and inner walls of buildings and structures with a relative humidity of air in the premises of not more than 75% in a non-aggressive environment (6.2.3 CTO 501-52-01-2007 Part I).
When using aerated gas-concrete blocks in wet rooms, it is necessary to provide measures aimed at waterproofing the masonry, for example, to treat it with water-repellent compounds[4].
The general trend in the world development of the reinforced concrete industry is the development of the flexibility of the manufacturer to the needs of the customer and the possibility of using prefabricated concrete products for the construction of open-plan buildings in the shortest possible time with a guaranteed high quality of the reinforced concrete product. The design of the prefabricated frame provides an acceleration of the construction time of objects due to the prefabrication of elements and a significant simplification of the installation technology of the structure. The use of modern technologies for the manufacture of prefabricated concrete, including
Central Asian Research Journal For Interdisciplinary Studies (CARJIS)
ISSN (online): 2181-2454
Volume 2 | Issue 5 | May, 2022 | SJIF: 5,965 | UIF: 7,6 | ISRA: JIF 1.947 | Google Scholar |
www.carjis.org DOI: 10.24412/2181-2454-2022-5-41-46
prestressed concrete, makes it possible to reduce labor costs, material consumption and energy intensity of construction. Factory manufacturing technology of structures at all stages provides quality control of products. Reducing the energy consumption of the construction industry starts with the choice of materials for building structures. The undisputed leadership in load-bearing frames remains with reinforced concrete and metal, but for building enclosing structures, the use of materials based on energy-intensive processes (vibroforming, baking, steaming) is unreasonably expensive [5].
DISCUSSION
Frame-sheathing wall (FSW) is a multilayer combined structural system consisting of a frame (skeleton), materials for insulation / sound insulation that fill the cavity of the frame, wall sheathing (external and internal), fasteners, vapor barrier and wind protection, external cladding (facade), as well as a set of technical and technological solutions that determine the rules and procedure for installing this system in the design position.
FSW with the use of LSTS - frame-sheathing walls, the frame of which consists of steel bent galvanized profiles.
LSTS - structures made of bent galvanized steel thin-walled profiles, an abbreviation for a wide range of structures made of bent cold-rolled profiles used in construction[6].
The use of lightweight steel thin-walled structures opens new opportunities for improving the quality of construction. The advantages of LSTS are reliability and long service life, wide architectural possibilities, low specific weight of structures, resistance to seismic and other dynamic loads, fast all-season installation of structures, low operating cost, and the possibility of effective repair and reconstruction^, 8]. With the use of LSTS, both residential buildings and industrial buildings and structures are being built. In developed countries, the advantages of LSTS have already been appreciated, and buildings made from LSTS occupy a significant share: in the UK - 20%, Sweden and Japan - 15%, Canada - 10%, USA -depending on the region 5-15% of the total residential construction[9].
In multi-storey buildings (above 3-4 floors), LSTS represented by FSW are used as non-load-bearing enclosing structures. Simplicity, speed, and ease of installation of thin-walled structures, the ability (in most cases) to do without lifting mechanisms, increases labor productivity by 1.5-2 times. The absence of "wet" processes during the construction of load-bearing and enclosing structures allows
Central Asian Research Journal For Interdisciplinary Studies (CARJIS)
ISSN (online): 2181-2454
Volume 2 | Issue 5 | May, 2022 | SJIF: 5,965 | UIF: 7,6 | ISRA: JIF 1.947 | Google Scholar |
www.carjis.org DOI: 10.24412/2181-2454-2022-5-41-46
construction and installation work all year round, in almost all-weather conditions and climatic zones. The low weight of the structures helps to reduce the cost of transportation to the construction site and reduces delivery times. In addition, the total load from the building on the foundations is reduced, which makes it possible to design the foundations of simplified structures[10].
To improve the manufacturability of the construction of frame and panel buildings, reduce the time and energy consumption of construction in the world, the technologies of light enclosing structures are increasingly used[11]. Light walls are self-supporting external walls made of sheet materials and an insulating layer. In Europe, light enclosing structures are used mainly in the technologies of "quick" cottage construction and are popular in northern European countries. For example, in Finland, frame housing accounts for 75%, and in Sweden they account for up to 90% of new cottages. The use of a metal frame in these structures made it possible to improve their manufacturing quality and reliability, as well as to solve fire safety issues, which opened the possibility of using such products as external walls of multistorey buildings. Therefore, now in Sweden, Norway and Finland, the use of light hinged walls in multi-storey buildings reaches up to 70% of the market, in the Netherlands and Germany - up to 50%.
The stability of the geometry of structures based on a metal frame is ensured by the high dimensional accuracy of steel profiles, which, unlike wood, are not affected by biological and humidity-temperature processes and are characterized by the absence of shrinkage during construction and operation. The technology of light steel thin-walled structures (LSTS) in the construction of individual housing has been used in the world for more than 50 years [5].
CONCLUSION
Frame-sheathing walls made of light steel structures have many positive properties than traditionally used materials in construction, such as brick and concrete. However, some issues of their use in seismically active areas and their influence on the overall rigidity of the building frame of such enclosing structures have been little studied, which requires a deep detailed study for the use of such structures on the territory of Uzbekistan.
REFERENCES
1. Grinfeld G.I. Enclosing structures of frame buildings using autoclaved aerated
Central Asian Research Journal For Interdisciplinary Studies (CARJIS)
ISSN (online): 2181-2454 Volume 2 | Issue 5 | May, 2022 | SJIF: 5,965 | UIF: 7,6 | ISRA: JIF 1.947 | Google Scholar |
www.carjis.org DOI: 10.24412/2181-2454-2022-5-41-46
concrete in St. Petersburg: problems, solutions.
2. Album of components and technical solutions for use in projects of residential and public buildings with more than 3 storeys in areas with seismicity of 7, 8 and 9 points. ATR BGB 4.1-2015.
3. Poddubnyak M.D. Constructive solutions for filling the supporting frame of buildings with autoclaved aerated concrete in seismically hazardous areas, Yekaterinburg 2017.
4. Album of technical solutions, version 10.2012, "Blocks of autoclaved cellular concrete for use in the construction and reconstruction of buildings and structures."
5. Dubatovka A.I. Modern constructive solutions of frame buildings with the use of light enclosing structures.
6. Album of technical solutions Knauf AQUAPANEL® External wall. External non-bearing frame-sheathing walls with a frame made of steel thin-walled cold-formed galvanized profiles using Knauf materials.
7. Kurazhova V.G., Nazmeeva T.V. Types of nodal joints in light steel thin-walled structures. Inzhenerno-stroitel'nyi zhurnal. 2011. No. 3(21). pp. 47-52.
8. Petrov K.V., Zolotareva E.A., Volodin V.V., Vatin N.I., Zhmarin E.N. Reconstruction of the roofs of St. Petersburg on the basis of light steel thin-walled structures and an anti-icing system. Inzhenerno-stroitel'nyi zhurnal. 2010. No. 2. S. 59-64.
9. Zhmarin E.N. International Association of Light Steel Construction // Internet journal "Construction of unique buildings and structures", 2012, No. 2, P. 27-30.
10. Bezborodov Evgeniy Leonidovich - "External walls with a frame of light steel thin-walled structures (LSTC)".
11. Dubatovka, A.I. Structural systems of buildings with the use of enclosing structures from wall panels based on glass-magnesite sheets: dis. ... master of construction: 05.23.01 / A.I. Dubatovka. - Minsk: BNTU, 2012. - 86 p.
