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The main problems of multilayer outer brick walls with tile efficient insulation in mass housing construction in Russia...
x2 =1 +
(6)
S =(x2 - x1)- (s2 - s1).
В случае учтены лишь цепи наветренного сторона якорной системы. Для учета влияния цепей подветренного сторона в том случае, когда это влияние существенно, особенно на глубине дна моря, составим аналогичные уравнения:
, Х3 у.
ch — — 1 +-;
S — (xj - x3) - (- a3sh—).
(7)
Здесь: х3 — горизонтальная проекция свободного провиса цепа подветренного борта установки; а3 — диаметр цепной линии.
Заключение
Итак, решив эти уравнения можно построить график зависимости Н02 (S) и Н03 (S).
Обе указанные зависимости Н02 (S) и Н03 (S) на общем графике и, учитывая, что Q= Н02 - Н03 можно построить графическую зависимость Q(S), т. е. зависимость между внешней силой и перемещением ППБУ при известном первоначальном натяжении цепа.
Список литературы:
1. Hümbatov H. H., Babayev V. Э. Daniz neft madan hidritexniki qurgularin tamiri va istismari. - Baki: Elm, 1990.
2. Давыдов И. Н. Определение усилий в швартовых бриделях от динамического действия ветра и волн.// Судостроение, - № 4. - 1982.
3. Чекмарев А. И. Влияние постоянной силы в нелинейных системах.// Инженерный сборник, АН СССР, 1978. - Т. IV. - Вып. 2.
4. Рза-заде С. А., Эюбов С. И., Ширинов М. М. и др. К вопросу определения смещения водоизолирующей колонны при спуске её на дно моря под действием горизонтальной распределённой нагрузки переменной интенсивности. - ANT. - № 6. - 2009.
Ogandzhanian Gagik Sergeevich, Candidate of technical sciences, CEO LLC ".LAD Systems", Moscow, Russia E-mail: lad_sistems@mail.ru
Ogandzhanian David Gagikovich, Student at «MATI - Russian State Technological University named after K. E. Tsiolkovsky», Moscow
The main problems of multilayer outer brick walls with tile efficient insulation in mass housing construction in Russia and their innovative solutions
Abstract: The article summarizes the main structural problems of multi-layer outer brick-clad walls with efficient insulation in low budget low/high-rise residential buildings in Russia, provides rationalization for developing scientific and technological basis for production of innovative wall foamthermoblock systems and using them when constructing multilayer outer walls. Rigid polyurethane foam, being used as high performance insulation material as well as material to form blocks, allows to make long-life building facades with the modest thicknesses and weigh with high thermotechnical, insulating and strength characteristics.
Keywords: multi-layer wall, efficient insulant, rigid polyurethane, high adhesive property, composite foamther-moblock.
When assessing the energy efficiency, it is the building envelope that determines up to 40 % of the overall heat loss. Nowadays, with all the range of outer wall structures the Russian building community has in possession, the variety of low budget walls in demand by housing market
and technological structures is not large. Today about 25 % of all facade structures of low/high-rise residential buildings in Russia have multilayer outer walls of hollow brickwork (face brick + insulant + reinforced concrete, lightweight concrete or ceramic block, etc.).
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Section 6. Technical sciences
Despite the number of researches of the similar structures held during the last years, there is no duly executed scientific and technological basis for their fitness. Mostly, it is caused by new innovative construction materials (constructive and efficient insulants, etc.), constructive building solutions and progressive construction technics (monolithic technologies, etc.) for the past decade and delay in their complex research. The legal and regulatory basis for introduction of innovative construction solutions and materials in construction area in Russia is “Technical fitness approval of new product for construction purposes at the territory of the Russian Federation”, issued based on decision of Federal autonomous institution “Federal center for regulation, standardization and technical assessment in construction” (FAU “FСC”), embracing full range of necessary scientific and technological research.
With introduction of new constructive solutions and optimization of energy consumption regulations for residential areas, the legal and regulatory basis, developed for precast large-panel house building, rapidly growing since mid-20th century, as well as for buildings with stone (brick) walls does not correlate to requirements of modern construction technologies. Nevertheless, the volume of construction of residential low/high-rise buildings with similar brick-clad wall structures has been growing since late 90s in all Russian regions, on account of being in demand and relatively cheap. Each year about 80 mln. sq. m. is being built in Russia, with 2 billion sq. m. being required in the coming decades.
Tightening of energy consumption regulations for residential areas [5] indispensably leads to use of efficient insulation in constructive layers of outer walls. The use of efficient insulation in outer walls allows to significantly lower heat loss, also thinning the wall thickness in general. Thus, while brick outer walls without efficient insulant in Central Russia shall be as thick as 2000 mm. out of heat saving requirements, 200 mm. is enough when using the efficient insulant.
This fact determined the designers’ choice of multilayer constructive solutions with application of efficient insulant for outer walls of buildings that have been massively constructed in the last 2 decades. The so-called “layered” or hollow brick-work, for example, three-layered, is based on use of heat saving insulant as a middle layer between the outer nonbearing layer (decorative protective, made of brick or other small piece material) and the inner bearing layer of the wall.
Since the year 2005, design of wall structures in blocked house buildings has been done according to the
album “Buildings with blocked concrete bearing structures. Outer brick-clad walls of lightweight concrete. Technical solutions”, developed by Central Research Institute of Engineering Residental Design together with Central Research Institute of Construction Structures named after V. A. Kucherenko based on the current regulations. However, lately, collapse of walls due to split or fall of parts of brick facing of different size has been happening in the buildings constructed using the three layer outer wall method (pic. 1) [6].
Even taking into the account the unconditional advantages of multi-layer constructive solutions with efficient insulation over one-layered, the lack of necessary scientific and technological basis leaves open the main problem of their use in construction.
The lack of adequate vapor barrier between the efficient tile insulation and adjacent wall layers typical of such wall structures means that the dew point is situated in the inner face brick layer of the wall, leading to freezing of moisture, accumulated in the “body” of the face brick, which is numerously prone to freezing and defrosting throughout a year.
Taking into account the fact that face brick is a rather long-life material, its collapse in the outer wall is mostly attributed to the proximity and interaction with efficient insulation [1; 3; 4]. Thus, mechanical and physical, chemical and other features of the efficient tile insulation as well as terms of interaction with adjacent materials, determines the quality of outer walls. It requires experimental research and development of new production technologies, aimed at introduction in mass housing construction of innovative high-efficient (energy saving and long-life) materials in outer walls.
Besides, the main disadvantages of multi-layered outer brick-clad walls with efficient tile insulations shall be:
1. Low heat transfer performance uniformity factor of the wall due to the presence of thermally conductive inclusions such as construction concrete and other elements (metallic forces);
2. Heat loss through inter-floor slabs may account up to 50 % of total heat-loss of the wall;
3. Separate alterations of layers: thermal alterations of inner concrete formwork and outer brick work will differ considerably (concrete structure will always work in positive temperatures, since the whole formwork is closed by the middle thermal insulation layer, while the face brickwork will have to work in winter in negative temperatures);
4. these systems have limited possibilities for fa$ade levelling in case of departure from design evaluation (if
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The main problems of multilayer outer brick walls with tile efficient insulation in mass housing construction in Russia...
the framework departs from design vertically, it is ex- 8. mostly unrepairable (even slight repair and restora-
tremely difficult to level it with the help of brickwork); tion works require complete dismantling of the system);
5. labor-intensive process of construction; 9. Concrete construction tolerance doesn’t meet the
6. wide range of concealed works; requirements, for ex., a part of floorings oversails, while the
7. difficulty in observing horizontal joint sizes be- other part is concealed, thus, support of the facing work
tween the coping and the clab during brickwork; mostly reaches 2-3 cm. instead of 10-12 cm. per design.
Pic. 1. Demonstration of problems with multi-layer brick facades [6]
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Section 6. Technical sciences
The advantages of multi-layered brickwork shall be:
1. relatively thin and light outer walls, consequently, their low cost.
2. high thermal resistance of outer walls;
3. low consumption of materials
4. high degree of fire resistance (brick veneer walls may be used in buildings of any degree of fire resistance);
5. appealing exterior in demand by housing market;
6. simple tool kit;
7. customary erection method;
8. possibility of carrying out construction works throughout the year.
It is sad to note that nowadays the lack of low budget constructive solutions for multi-layered walls with
application of efficient insulation backed by the necessary legal and regulatory basis and in demand by the market suitable for the Russian climate is a major problem for the construction community. Moreover, the destructive processes going in these structures led to them being forbidden [2].
In view of the above, since the year 2014, LLC “LAD Systems” has developed in its laboratory the pilot production and is making research of innovative system of composite wall bock — foamthermoblocks for outer walls, including all structural wall layers — effective insulations, brick facade and inner layer (Pic. 2). Production of composite structural wall foamthermoblocks is based solely on high adhesive quality of rigid polyurethane towards different materials during foam forming, while grouting interstructure space of polyurethane.
Pic. 2. LLC «LAD Systems» Foamthermoblock (250 mm thick version) (n — number of bricks in the block;
A — thickness of outer layer made of face brick; B — thickness of inner layer made of ceramic stone, silicate, concrete or other material; C — thickness of the layer of poured efficient insulation made of rigid polyurethane; 88 (65) — height of standard face brick in Russia, mm.; 10 — thickness of vertical masonry joint, mm.)
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The main problems of multilayer outer brick walls with tile efficient insulation in mass housing construction in Russia...
The use of rigid polyurethane as an insulation and binding material for getting geometrically perfect wall blocks of the lowest weight, higher thermo technical and strength characteristics as well as high strength-density ratio in special press-forms (matrices) solves many problems, emerging in outer walls.
The innovative quality of the composite structural wall foamthermoblocks is its usage of ingenious combination of heat insulating (thermal conduction coefficient, \ = 0.025 W/m-°C), vapor insulating (vapor transmission coefficient p = 0.018 mg/m-hr-Pa) and high adhesive qualities of rigid polyurethane towards different materials for getting composite structural wall foam blocks, providing the in-demand fa$ades of face brickwork of minimal thinness.
The researches are planned to be held to design algorithms of thermotechnical and strength calculations of wall structures and, as a whole, to develop scientific and technological basis for introduction of an innovative product with exaplanation of the following main technical parameters:
- universality principle of foamthermoblocks;
- Optimization of geometric formats of foamthermoblock systems for various climates depending on its strength and heat-saving requirements;
- Pilot design of the building with outer wall out of foamthermoblocks;
- Within cooperation with strategic partners, introduction during construction of pilot
residential building with outer walls made of foamthermoblocks and further increase of its volume in construction of low/high-rise buildings.
Whereby, among the key expected competitive advantages of the innovative product under development are:
- availability of legal and regulatory basis and scientific and technological basis for production and introduction of an innovative wall energy-efficient foamthermoblocks, providing the outer wall construction with the necessary operational qualities;
- lasting quality;
- thin outer walls, allowing to enlarge usable floor area;
- light weight of outer wall, resulting from minimal thickness, leads to less load on the bearing structure;
- low cost (cost effective) due to low material consumption and high technological effectiveness of foamthermoblocks production and brickwork process (preliminary, introduction of foamthermoblocks will cut cost of facades by 170 %);
- high technological effectiveness of working process and, as a result, good performance while building outer walls is reached by low material consumption of structures and realization of low productive brickwork in workshops, using enlarges foamthermoblocks formats.
References:
1. Ищук М. К., Зуев А. В. Исследование напряженно-деформированного состояния лицевого слоя из кирпичной кладки при температурно- влажностных воздействиях.//ПГС - № 3. - 2007. - С. 40-43.
2. Журнал «Технология строительства». - № 1. - 2009.
3. Новиков А. В. Дефекты в облегченной кирпичной кладке.//Кровля. Фасады. Изоляция. - № 6. - 2007.
4. Новиков А. В. Причины возникновения дефектов в облегченной кладке./Технология строительства. -№ 4 (52). - 2007.
5. Федеральный закон от 23 ноября 2009 г. № 261-фз «Об энергосбережении и о повышении энергетической эффективности и о внесении изменений в отдельные законодательные акты Российской Федерации».
6. [Electronic resource]. - Available from: http://parthenon-house.ru/content/articles/index.php?SECTION_ ID=265
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