90
SPECIAL SLIDING BELT SUPPORTS THAT PROTECT BUILDINGS AND
STRUCTURES FROM EARTHQUAKES
candidate of technical sciences, professor S.M. Makhmudov
doctoral student (PhD) Sh.Kh. Samieva
doctoral student (PhD) O.I. Goyibov
Tashkent Architecture and Civil Engineering University (Construction engineering
technology). student D.A. Tursunov Polytechnic University of Turin.
Abstract. Current available methods of seismic in this article the insulation of
construction structures is considered, a critical analysis of which is carried out. The mechanism
was developed in the construction of a seismic insulation Foundation based on ftoroplast, the
disadvantages of similar seismic insulation systems prior to elimination. It is possible to move
the building in the amount of displacement of the base during the seismic insulation to maintain
the spatial rigidity, the structure of the earthquake. The introduction of a seismic isolation
mechanism into the foundation structure is shown allows you to reduce stresses in construction
structures. It is proposed to introduce a seismic insulation mechanism into the foundation
structure, which will reduce the likelihood of collapse of the structure, which will ensure the
safety of human life and expensive equipment, and expensive prevent structural restoration
measures, as well as reduce the consumption of reinforcement, recommendations have been
made to make the construction of the building more economical.
Keywords: Seismic danger, active method, seismic isolation, buildings and structures,
acceleration vector.
Introduction. The seismic danger in the world is always great and has only been increasing
in recent years. Russia is on a par with the most seismically active countries, such as Japan, the
USA, Turkey, China, Italy. The highest seismic hazard is characteristic of the southern and
eastern regions of Russia – the Far East, the North Caucasus, Siberia. The seismic activity of
Krasnoyarsk is estimated at 5-6 points, while its territory is heterogeneous in geological
structure, which may lead to an underestimation of the expected shaking by 1-2 points.
Earthquakes are considered dangerous for buildings and structures, the intensity of which
reaches 7 points or more, because they are accompanied by the destruction of non-earthquake
resistant buildings and structures, the death of people and the destruction of material and
cultural values. Ensuring the safety of people and the safety of buildings and structures during
earthquakes is the most important scientific, technical and socio-economic problem of all
seismically active countries. Traditional methods and means of protecting buildings and
structures from seismic impacts are currently the main ones in construction practice. They
include a large complex of various measures aimed at increasing the load-bearing capacity of
building structures, the design of which is carried out on the basis of norms and rules developed
by domestic and foreign construction experience that guarantee earthquake resistance of
buildings and structures in areas with seismicity of 7, 8 and 9 points (Figure 1).
Figure 1
. The object of the study of this work relates to the active method of seismic
isolation.
Seismic protection methods
Passive
Active
Comprehensive
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The design of buildings and structures in seismically hazardous areas begins with
compliance with the general principles of earthquake-resistant construction, according to which
all used building materials, structures and structural schemes should provide the lowest value
of seismic loads. It is recommended to adopt, as a rule, symmetrical design schemes when
designing and to achieve a uniform distribution of structural stiffness and mass. It is necessary
to comply with the requirement of equal strength of the elements of load-bearing structures,
weak nodes and elements should not be allowed, the premature exit of which can lead to the
destruction of the structure, until the exhaustion of its bearing capacity. In buildings and
structures made of prefabricated elements, it is recommended to place joints outside the zone
of maximum effort, it is necessary to ensure the uniformity and solidity of structures through
the use of reinforced prefabricated elements. In modern earthquake-resistant construction, it is
extremely important to ensure the reliability of buildings and structures, subject to the rational
consumption of additional materials, funds and labor costs for their ant seismic reinforcements.
The traditional method of ensuring earthquake resistance of structures provides
for an increase in the bearing capacity of structures by increasing their size and strength of
materials, and in buildings with load-bearing brick walls, the use of antiseismic belts, reinforced
concrete inclusions, additional reinforcement of piers, the intersection of longitudinal and
transverse walls, all this requires a significant increase in the number of building materials and
facilities. An increase in the amount of material leads to an increase in the rigidity and weight
of the structure, which in turn causes an increase in inertial loads. The active method allows to
reduce seismic loads on the building by means of regulating their dynamic characteristics
during the oscillatory process during an earthquake. The dynamic parameters are regulated in
such a way as to avoid a resonant increase in the oscillation amplitudes of the structure, or at
least to lower the resonant effects.
Results and its discussion. The mechanism of seismic isolation is performed as follows.
The foundation plate is arranged in the form of a "trough", the displacement limiters are made
in such a way that a gap (0.5 m) is formed between the lower plate of the building and the walls
of the limiters, which makes it possible for the building to move in all directions by the
displacement of the base. Rubber dampers are supplied in the gap. Two layers of ftoroplastic
film (δ = 4-6 mm) are laid on the surface of the foundation plate, the lower reinforced concrete
slab of the building is concreted on the upper layer, and the building itself is erected on it.
During an earthquake, a foundation plate with displacement limiters and a lower layer of
fluoroplastic film will repeat the vibrations of the base. The building with seismic-insulating
sliding belts works as a system with switching off and on communication. With horizontal
forces at the level of the sliding belt, there are less dry friction forces, the building works as
with a rigid connection, and accelerations of the moving base are transmitted to it. If the
magnitude of the horizontal forces at the level of the sliding belt is greater than the dry friction
forces, the slippage of the building relative to the foundation is realized, the rigid connection is
turned off, and the above ground structures above the sliding belt pass into a qualitatively new
state. The seismic isolation system operates at 3 states under the influence of seismic loading
(Fig 2.). With static calculation, it is possible to determine the angle of inclination α for each
state:
According to Building standards rules 2.01.03-19 Construction in seismic areas, the
seismic load is determined by the equation (1).
𝑺
𝒊к
= К
𝟏
∙ К
𝟐
∙ 𝑺
𝒐𝒊к
= К
𝟏
∙ К
𝟐
∙ 𝑸
К
∙ 𝑨 ∙ 𝜷
𝟏
∙ К
𝝍
∙ 𝜼
𝑰𝑲
(1)
For an ordinary building of 8 floors in a 9-point seismicity zone:
К
𝟏
= 𝟎, 𝟐𝟓
(The coefficient of permissible damage to the building);
К
𝟐
= 𝟏, 𝟑
(Coefficient of the constructive solution of the building);
𝑨 = 𝟎, 𝟒
(Acceleration vector of the foundation of the building zone);
𝜷
𝟏
= 𝟑
(The coefficient of dynamism of the building);
К
𝝍
= 𝟏, 𝟏
(Building flexibility coefficient).
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State I, On the element of the seismic isolation system, the vertical load
𝑸
К
from the
weight of the building and the transverse load Sik from the seismic act (Fig.2).
Fig.2. State I of the elementary seismic isolation system.
State II, after exceeding a certain threshold value of the seismic load, the shift in the
horizontal direction on the insulating layer is greater than the friction of rest, the sliding surface
begins to slide to play the role of seismic insulation (Fig.3).
Fig.3. The state of the II elementary seismic isolation system.
State III, the return of the upper part of the building to its original position (Fig.4).
Fig.4. The state of the III elementary seismic isolation system.
Based on the analysis, we will plot the slope angle and optimize it (Fig.5):
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Fig.5. Building sliding slope scheme.
Based on the above, the construction of buildings with a seismic isolation sliding belt is
established in accordance with the Ministry of construction of the Republic in relation to
traditional building solutions, based on the calculation of the feasibility of the project solution.
Due to the use of a seismic isolation slip belt, the calculated seismicity of the building is reduced
by one point (horizontal seismic forces calculated on terrestrial structures are doubled). At the
same time, it is achieved to save steel by 5-7% and reduce the estimate value by 3-6%. In
relation to traditional building, in coordination with the Ministry of construction of the
Republic, the construction of buildings with a seismic isolation sliding belt will be carried out
on the basis of the calculation of the technical and economic efficiency of the project.
When developing design solutions for buildings with a seismic isolation sliding belt, it
is necessary to use standard solutions of building structures. In this case, surface structures,
however, are adopted unchanged, and the development of sliding belt elements is carried out at
the same time as the design of foundations for buildings in accordance with these
recommendations. The seismic isolation sliding belt is carried out as follows; between the
foundation of the building and the above-ground construction, it is placed at a number of
supports at the intersection of longitudinal and transverse walls.
Conclusion: The result of calculating a 9 - storey residential building with a seismo -
insulating slip belt to a 9-magnitude earthquake showed that compared to a non-seismo-
insulated building, the calculated earthquake force-by 2 points, horizontal seismic forces
calculated on ground structures-were found to be reduced by two times. At the same time, the
volume and steel consumption of anti - earthquake measures were analyzed, a decrease of 5-
12% in comparison with buildings with conventional structural schemes, and a decrease in the
estimated cost of buildings by 3-6%. For buildings built in areas with scores of 8 and 9, it is
preferable and economically desirable to use a sliding belt.
LITERATURE:
1.
Machmudov S. M., Samieva S. K. Quantitative assessment of the reliability of the
system" foundation-seismic isolation foundation-building" //Central Asian Journal of STEM. –
2021. – Т. 2. – №. 2. – С. 445-452.
2.
Khakimov G. A. et al. COMPACTION OF LOESS BASES OF BUILDINGS AND
STRUCTURES, AS WELL AS BULK SOILS AROUND THE FOUNDATION USING
VIBRATORY ROLLERS IN SEISMIC AREAS //Galaxy International Interdisciplinary
Research Journal. – 2023. – Т. 11. – №. 4. – С. 306-311.
3.
Махмудов С. М., Самиева Ш. Х. КОНСТРУКТИВНЫЕ РЕШЕНИЯ
СЕЙСМОИЗОЛИРУЮЩИХ ФУНДАМЕНТОВ ЗДАНИЙ //НАУЧНЫЕ РЕВОЛЮЦИИ
КАК КЛЮЧЕВОЙ ФАКТОР РАЗВИТИЯ НАУКИ И ТЕХНИКИ. – 2021. – С. 36-38.
4.
Samiyeva S. K., Makhmudov S. M. SEISMIC ISOLATION SYSTEM AND
SEISMIC DAMPERS. – 2022. Национальное объединение изыскателей и
проектировщиков
(НОПРИЗ),
Национальный
исследовательский
Московский
94
государственный строительный университет (НИУ МГСУ), Научно-исследовательский
центр "Строительство" (АО "НИЦ "Строительство").
5.
GMFN, Dos, Samiyeva Sh Kh, and Master MA Muminov. "DEFORMATION OF
MOISTENED LOESS FOUNDATIONS OF BUILDINGS UNDER STATIC AND DYNAMIC
LOADS." (2022). European Journal of Research Development and Sustainability, 3(12), 44-48.
Retrieved from https://scholarzest.com/index.php/ejrds/article/view/3049.
6.
Махмудов С., Гойибов О. СТАТИСТИЧЕСКОЕ МОДЕЛИРОВАНИЕ
СЕЙСМИЧЕСКИХ ВОЗДЕЙСТВИЙ //Центральноазиатский журнал образования и
инноваций. – 2023. – Т. 2. – №. 6 Part 3. – С. 85-91.
7.
Khakimov, G., Abduraimova, K., Askarov, M., & Khakimova, M. (2023).
INFLUENCE OF HUMIDITY ON CHANGES IN THE STRENGTH CHARACTERISTICS
OF LESS SOILS UNDER SEISMIC INFLUENCE.
International Bulletin of Engineering and
Technology
,
3
(6), 274-281.
ЭКСПЕРИМЕНТАЛЬНЫЕ ИССЛЕДОВАНИЕ СЕЙСМОСТОЙКОСТИ
ЗДАНИЙ С УЧЕТОМ КРУТИЛЬНЫХ КОЛЕБАНИЙ
Абдурашидов К.С., Рахманов Б.К., Рахманова Х.
Ташкентский архитектурно-строительный университет,
100095, Ташкент, улица Янгишахар, 9А
Maqolaning qisqacha mazmuni. Мақолада иншоотлар зилзилабардошлиги назарий
ва экспериментал тадқиқот натижалари таҳлил этилган ва интрументал
тадқиқотлар ҳақиқатга яқин натижалар бериши келтирилган.
Kalit so’zlar: bino, inshoot, nazariy-ekspemental tadqiqotlar, zilzilabardoshlik,
tadqiqot uslubi, zilzila, muhandislik tahlil, seysmik zo’riqish, instrumental uslub, tebranish,
seysmometrik asboblar, dinamik tavsiflar
Аннотация. В статье приведены анализ результатов теоретического и
экспериментального исследование сооружений и установлено что инструментальные
исследование даёт достоверные результаты.
Ключевые слова: здание, сооружение, экспериментально-теоретические
исследования, сейсмостойкость, метод исследования, землетрясение, инженерный
анализ, сейсмическое усилие, инструментальный метод, колебания, сейсмометрические
приборы, динамические характеристики колебаний
Annotation. The article presents an analysis of the results of theoretical and
experimental research of structures and it is established that instrumental research gives
reliable results.
Keywords: building, structure, experimental and theoretical studies, seismic resistance,
research method, earthquake, engineering analysis, seismic force, instrumental method,
vibrations, seismometric instruments, dynamic characteristics of vibrations.
Введение.
Одна из проблем теории сейсмостойкости заключается в том, что
сейсмические усилия, определяемые различными способами, не согласуются между
собой, в силу чего степень достоверности расчетов, выполняемых при проектировании
сооружений остается недостаточно выясненной. Соответственно задача обеспечения
сохранности зданий и сооружений при сильных землетрясениях еще далека от
окончательного решения и требует дальнейших исследований, особенно различных
вопросов сейсмостойкости сооружений инструментальными методами. [1]
Кроме того, тщательный анализ развития научных исследований показывает, что
оно в настоящее время происходит неравномерно. Результаты теоретических
исследований, которые ведутся в широком масштабе, не могут быть внедрены в
практику строительства без высококачественной экспериментальной проверки.
