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Original article
77
УДК 38.71.72.(624)
RESEARCH OF WORKS IN THE PROCESS OF ASSEMBLY OF LARGE
INTERMEDIATE COLLECTION SHELLS AND DISASSEMBLY OF ASSEMBLY
EQUIPMENT.
Ravshanov Dilshod Xolmurodovich
master degree
Samarkand State Architecture and Construction University, Uzbekistan.
Annotation:
The article presents the results of experimental and theoretical studies of large-span
precast-monolithic reinforced concrete shells of complex geometry assembled from enlarged
assembly elements. The studies were conducted on full-scale composite shells with a span of
72m, their enlarged elements of 3 × 18 m as well as on a shell model at a scale of 1:10 and 1:4.
The stress-strain state of shells of this type was studied for different options of assembly and
unscrewing of the structure. Recommendations are given on rational methods of constructing
shells from enlarged elements for unique public buildings. [2,4].
Key words:
reinforced concrete, long-term, shell, installation, unique buildings, enlarged element.
1. Introduction.
Recently, in the development of the theory of deformation of reinforced
concrete, certain efforts have been made to develop complex-deformation conditions. However,
it cannot be said that the possibilities for supporting the unique buildings used for reinforced
concrete purposes for various purposes are not yet widely used. The study of reinforced concrete
and simple geometric shapes based on modern deformation theory is intended to use numerical
methods for the nonlinear calculation of the main algorithms of cracked reinforced concrete.
Thus, the combined use of certain complex-deformation methods in the assembly state, together
with the development of more effective methods and algorithms for practical calculations in the
transition from the assembly state to the operational state, creates a way to develop more
effective methods and algorithms for the transition from the assembly state to the operational
state.The work based on the works approved by us [3,5] was used to develop methods for the
static calculation of reinforced concrete assemblies in such a production process, taking into
account physical and geometric nonlinearities.The purpose of this work is to consider the state of
deformation during the restoration of buildings.The complex deformation state of the products
under consideration during the installation process requires the creation of certain conditions for
obtaining specific properties of reinforced concrete. Including the adoption of a number of tables
of physical and geometric nonlinear problems for the calculation of reinforced concrete during
installation.1. The surface of the shells is considered to be ribbed, without special holes. The
surface of the shells has various imperfections. The shells are considered to be continuous
(variable).2. The main assumptions of the theory of plane properties are the rules. The normal
assumption of the initial value for the cross section of reinforced concrete dimensions.3. The
equilibrium equations of the shell element are formulated taking into account the deformation of
the middle surface. We make deformations, assume nonlinearity of the connection for the
qualitative and quantitative characteristics and displacements.4. The deformation state of the
shells during the transition to the installation and operation process is considered. The static
installation load is assumed to be short-term and constant. It is impossible to exclude the
possibility of a continuous increase in loads for the deformation state under the influence of
ISSN: 3030-3931, Impact factor: 7,241
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Original article
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static loads.5. The shell material is assumed to be nonlinearly elastic in compression and brittle
in tension with cracks (cracks). The criteria for deformation, crack generation and load bearing
(strain) are developed according to the modeling theory. The concrete deformation law is briefly
written as nonlinear algebraic equations under static loading, and nonlinear differential equations
under constant loading under flow theory.[7,8,11].
Figure 1. Dependence of technical and economic indicators on the size of reinforced concrete
shells.
2. Research objectives.
The use of the modeling method is one of the most effective tools for
studying the assembly and disassembly of reinforced concrete spatial structures. In many cases,
serious difficulties are encountered in the calculation of such structures, taking into account all
their specific features. The modeling method allows you to conduct studies of the stress-strain
state of the structure; assess the accuracy of its calculation methods, and compare the results of
individual tests with a number of different-scale connections of structures of this class under
varying stress-strain conditions.[9,10].Without the use of modeling, it is impossible to find new
constructive solutions and solve theoretical problems; testing models instead of natural tests in
the study of structures and structures allows you to save a significant amount of money. The
strength of various types of shell coatings. The evaluation of their priority, durability, crack
resistance and safety in the assembled state was carried out in accordance with [3]. However, it
should be noted that the specific characteristics of the state of such structures (including integral,
prefabricated) during assembly and disassembly are an area that has not been sufficiently studied.
Therefore, experimental studies were conducted on scale models M 1:4÷M 1:10, and then they
were tested on large-scale natural objects (Fig. 2).
Figure 2. The studied structural scheme of a 72 m span flat shell during the assembly phase.
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3. Research results
The general method of modeling is based on the theory of similarity. Three similarity theorems
were formulated in [40, 44, 60]. In the modeling process using these theorems, it is required to
know the equations that represent the phenomena under study in nature.
When modeling complex spatial systems, it is often not possible to write their stress-strain
equations of state. In this case, the application of similarity theory is important, as it allows you
to find connections that represent the phenomenon under study. In many cases, the same scale is
chosen for indicators with the same characteristics. The similarity indicator can be used to solve
these complexities. In general, the condition of nonlinearity and the conditions of integral
similarity are also formulated. In the modeling of reinforced concrete spatial structures during
the assembly and disassembly stages, we use extended mechanical similarity, in which the
mechanical similarity of deformation is proportional to the deformations of the natural model. In
both cases, the model must be geometrically consistent with nature. We will consider the
methodology for using the results of model tests to evaluate the performance of natural shell
structures.
Characteristics of the studied types of shells and models
Item
No.
Shells under study,
element marking
Sketch
Scale,
dimensions
in mm
Purpose
1
Compound
ribbed
side elements with
negative
Gaussian
curvature
M 1:10
4.8x4.8 m
Study of stress-strain state under assembly
loads . Evaluation of strength, rigidity
stability , crack resistance and safety under
various combinations of assembly loads;
identification of rational methods of
assembly and disassembly.
2
Compound
ribbed
with lateral elements
of negative Gaussian
curvature M-2
M 1:4
12x12 m
Study of stress-strain state during
installation and operational impacts
3
Shallow ribbed shells
of positive Gaussian
curvature
with
a
square plan
72x72 m
Study of stress-strain state at different
levels and combinations of assembly load.
Identification of rational methods of
assembly and disassembly of the shell.
List of used literature (References)
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external reinforcement. // On construction sites of Russia - 1987. No. 11. P. 7-11.
2. Ivovich V.A., Pokrovsky L.N. Dynamic calculation of hanging systems. - M .: Stroyizdat,
1989. - 312 p.
3.
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