scholarly journals ON THE ISSUE OF ESTIMATING THE EFFECTIVE LENGTH OF NON-CENTRALLY COMPRESSED REINFORCED CONCRETE ELEMENTS

2021 ◽  
pp. 17-29
Author(s):  
Sergey ZENIN ◽  
Ravil SHARIPOV ◽  
Олег КУДИНОВ
Keyword(s):  
Reinforced Concrete ◽  
Cross Sections ◽  
Research Work ◽  
Concrete Columns ◽  
Effective Length ◽  
Monolithic Columns ◽  
Structural Systems ◽  
Regulatory Documents ◽  
Concrete Elements

Research work was carried out at NIIZHB named after A.A. Gvozdev, one of the tasks of which was to study the influence of the conditions for stiff fixing supports on the parameters of the effective lengths of reinforced concrete columns with square and rectangular cross-sections assigned when calculating the strength of normal sections. As part of the study, the influence of different values and directions of the angles of rotation of the fixing and their displacements was evaluated. The conducted computational and theoretical studies based on the analysis of experimental data showed that the method of determining the effective lengths, adopted in domestic standards, can be improved. Based on the results of the research, proposals were formulated to take the results of the work into account in the current regulatory framework. Taking into account the peculiarities of the conditions for fixing the structures considered in the work, which correspond to the nature of the work of monolithic columns and pylons, it is recommended to include the provisions of the proposed methodology in SP 430.1325800.2018, which applies to monolithic structural systems of buildings. The prepared proposals for the calculation are supposed to be included in the current regulatory documents as one of the possible options for determining the effective length of non-centrally compressed elements when calculating their strength.

SETTING A DIAGRAM APPROACH TO CALCULATING VIBRATED, CENTRIFUGED AND VIBROCENTRIFUGED REINFORCED CONCRETE COLUMNS WITH A VARIATROPIC STRUCTURE

2020 ◽  
pp. 22-34
Author(s):  
Л. Р. Маилян ◽  
С. А. Стельмах ◽  
Е. М. Щербань ◽  
М. П. Нажуев
Keyword(s):  
Experimental Data ◽  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Cross Section ◽  
Concrete Columns ◽  
Reinforced Concrete Columns ◽  
The Cross ◽  
Concrete Elements ◽  
Diagram Approach

Состояние проблемы. Железобетонные элементы изготавливаются, как правило, по трем основным технологиям - вибрированием, центрифугированием и виброцентрифугированием. Однако все основные расчетные зависимости для определения их несущей способности выведены, исходя из основного постулата - постоянства и равенства характеристик бетона по сечению, что реализуется лишь в вибрированных колоннах. Результаты. В рамках диаграммного подхода предложены итерационный, приближенный и упрощенный способы расчета несущей способности железобетонных вибрированных, центрифугированных и виброцентрифугированных колонн. Выводы. Расчет по диаграммному подходу показал существенно более подходящую сходимость с опытными данными, чем расчет по методике норм, а также дал лучшие результаты при использовании дифференциальных характеристик бетона, чем при использовании интегральных и, тем более, нормативных характеристик бетона. Statement of the problem. Reinforced concrete elements are typically manufactured according to three basic technologies - vibration, centrifugation and vibrocentrifugation. However, all the basic calculated dependencies for determining their bearing capacity were derived using the main postulate, i.e., the constancy and equality of the characteristics of concrete over the cross section, which is implemented only in vibrated columns. Results. Within the framework of the diagrammatic approach, iterative, approximate and simplified methods of calculating the bearing capacity of reinforced concrete vibrated, centrifuged and vibrocentrifuged columns are proposed. Conclusions. The calculation according to the diagrammatic approach showed a significantly better convergence with the experimental data than that using the method of norms, and also performs better when using differential characteristics of concrete than when employing integral and particularly standard characteristics of concrete.

Designing Compressed Reinforcement Cross-Sections by Curvature and Nominal Stiffness Methods

2015 ◽  
Vol 797 ◽  
pp. 69-78
Author(s):  
Krzysztof Kamiński ◽  
Piotr Nowicki
Keyword(s):  
Reinforced Concrete ◽  
Comparative Analysis ◽  
Cross Sections ◽  
Concrete Columns ◽  
Computer Programs ◽  
Significant Issue ◽  
Reinforced Concrete Columns ◽  
Small Eccentricity ◽  
Standard Methods ◽  
Surface Reinforcement

The paper attempts to discuss the still significant issue of methods of design of the reinforced concrete columns according to PN-EN 1992-1-1:2008/A1:2015-03. Two algorithms of the dimensioning sections were developed according to two standard methods of dimensioning eccentrically compressed sections: the method of nominal stiffness (NS) and the method of nominal curvature (NC). Using both algorithms, computer programs in Excel were created. A comparative analysis of several examples of calculation were performed to compare the results of dimensioning of sections eccentrically compressed. The results obtained by the NC method give about 10% less surface reinforcement when loaded with big eccentricity and over 50% less when small eccentricity is applied.

scholarly journals Strength criterion for a plane stress reinforced concrete element under a special action

Vestnik MGSU ◽  
2020 ◽  
pp. 1513-1522
Author(s):  
Natalia V. Fedorova ◽  
Vu Ngoc Tuyen ◽  
Igor A. Yakovenko
Keyword(s):  
Reinforced Concrete ◽  
Progressive Collapse ◽  
Concrete Strength ◽  
Limit State ◽  
Strength Criterion ◽  
Structural Systems ◽  
Variable Loading ◽  
Concrete Element ◽  
Theory Of Plasticity ◽  
Concrete Elements

Introduction. Problem solving focused on the protection of buildings and structures from progressive collapse and minimization of resources, needed for this purpose, is becoming increasingly important. In many countries, including Russia, this type of protection is incorporated into national regulatory documents, and, therefore, any research, aimed at developing effective ways to protect structural systems from progressive collapse under special actions, is particularly relevant. In this regard, the present article aims to formulate effective strength criteria for such anisotropic materials as reinforced concrete to analyze plane stressed reinforced concrete structures exposed to sudden structural transformations caused by the removal of one of bearing elements. Materials and methods. To solve this problem, a variant of the generalized theory of plasticity of concrete and reinforced concrete, developed by G.A. Geniev, is proposed for application to the case of variable loading of a plane stressed reinforced concrete element. The acceptability of generalization of the strength criterion, pursuant to the theory of plasticity of concrete and reinforced concrete under static loading, and the applicability of this criterion to variable static-dynamic loading of reinforced concrete are used as the main hypothesis. An algorithm of an approximate method is presented as a solution to this problem; it allows to analyze the considered stress-strain state of plane stressed reinforced concrete elements. Results. The numerical analysis of the obtained solution, compared with the results of the experimental studies, was used to evaluate the designed strength criterion for reinforced concrete elements located in the area where the column is connected to the girder of a monolithic reinforced concrete frame in case of a sudden restructuring of a structural system. It is found out that the qualitative nature of the destruction pattern of the area under research, obtained in experiments, corresponds to the destruction pattern, identified by virtue of the analysis performed using the proposed criterion. Conclusions. The variant of the reinforced concrete strength criterion designated for the variable loading of a plane stressed reinforced concrete element and an algorithm for its implementation, based on the theory of plasticity of concrete and reinforced concrete developed by G.A. Geniev, is applicable to the analysis of a special limit state of reinforced concrete elements of structural systems of frames of buildings and structures.

scholarly journals Optimizing of system "column-cfrp lamellas" with the strengthening of civil structures

2021 ◽  
Vol 9 (1) ◽  
pp. 1-5
Author(s):  
Irina Mayackaya ◽  
Batyr Yazyev ◽  
Anastasia Fedchenko ◽  
Denis Demchenko
Keyword(s):  
Reinforced Concrete ◽  
Composite Materials ◽  
Carbon Fiber ◽  
Concrete Structures ◽  
Polymeric Composite ◽  
Concrete Columns ◽  
Reinforced Concrete Structures ◽  
Structural Elements ◽  
Civil Structures ◽  
Concrete Elements

Reinforced concrete elements of structures in the form of columns, beams, ceilings are widely used in the construction of buildings and structures of industrial and civil construction. In most cases, the columns serve as supports for other building elements, for example, crossbars, slabs, girders, beams. One of the cycles of the work of reinforced concrete structures is the state of their repair and reconstruction, including the stages of strengthening the elements. There is a problem of strengthening of reinforced concrete columns. The article deals with the issue of reinforcing columns and other structural elements having a cylindrical surface, with polymeric composite materials in the form of carbon fiber lamellae. The use of composite materials allows to increase the service life and strength of reinforced concrete structures used in construction.

scholarly journals Inelastic Effective Length Factor of Nonsway Reinforced Concrete Columns

2009 ◽  
Vol 135 (9) ◽  
pp. 1034-1039 ◽  
Author(s):  
A. Bendito ◽  
M. L. Romero ◽  
J. L. Bonet ◽  
P. F. Miguel ◽  
M. A. Fernandez
Keyword(s):  
Reinforced Concrete ◽  
Concrete Columns ◽  
Effective Length ◽  
Reinforced Concrete Columns ◽  
Effective Length Factor

Behaviour of Reinforced Concrete Columns of Various Cross-Sections Subjected to Fire

2016 ◽  
Vol 97 (3) ◽  
pp. 221-229
Author(s):  
Aneesha Balaji ◽  
K. Muhamed Luquman ◽  
Praveen Nagarajan ◽  
T. M. Madhavan Pillai
Keyword(s):  
Reinforced Concrete ◽  
Cross Sections ◽  
Concrete Columns ◽  
Reinforced Concrete Columns

Application Technology of Bamboo Reinforced Concrete in Building Structure

2012 ◽  
Vol 195-196 ◽  
pp. 297-302 ◽  
Author(s):  
Wei Feng Zhao ◽  
Jing Zhou ◽  
Guo Bin Bu
Keyword(s):  
Reinforced Concrete ◽  
Weight Ratio ◽  
High Strength ◽  
Concrete Columns ◽  
Building Structures ◽  
Structural Elements ◽  
High Tensile Strength ◽  
Application Technology ◽  
Steel Bar ◽  
Concrete Elements

Bamboo is mainly a tropical and subtropical plant which is found adequate in many countries. The strength of bamboo as concrete reinforcement is much lower than steel bar reinforcement. However, one of the merits is a cheap and replenishable agricultural resource and abundantly available. Due to excellent properties like high strength to weight ratio, high tensile strength and free-cutting and processing, bamboo as a potential reinforcement material in place of steel is widely available in concrete structural elements. The present paper introduces some of the existing studies and application technology of bamboo reinforced concrete elements in building structures, such as bamboo reinforced concrete columns, beams, slabs and walls.

scholarly journals Technical and economic efficiency of reinforced concrete elements with different types of reinforcement

2018 ◽  
Vol 196 ◽  
pp. 02030
Author(s):  
Ekaterina Efimenko ◽  
Liya Mailyan ◽  
Viktor Muradyan
Keyword(s):  
Reinforced Concrete ◽  
Building Materials ◽  
Full Employment ◽  
Concrete Columns ◽  
Longitudinal Force ◽  
Reinforcement Steel ◽  
Different Types ◽  
Effective Use ◽  
Concrete Elements ◽  
Economic Use

The article presents data on the bearing capacity of columns with various combinations of prestressed and conventional reinforcement. The areas of the most effective use of such structures with different eccentricities and flexibilities are shown. The ecology of reinforcement steel is an important task that the designers of reinforced concrete structures face. The creation of effective constructive solutions, that allow to combine high technical characteristics with economic use of reinforcement steel, has become urgent and is necessary for today's development of the construction industry. In the works [1,2,3,4,5] it was shown that the solution of these problems was possible by creating conditions for the full employment of building materials properties - reinforcement and concrete. The working reinforcement is characterized by its application in the conventional and prestretched forms. At the same time, the works done in the recent years show that reinforcement, subjected to precompression, can be used in the compressed zone [6,7,8]. It is most effective in rigid reinforced concrete columns. Thus, precompression of all longitudinal reinforcement or its part allows to increase the strength of non-flexible columns with not high relative eccentricities of the external longitudinal force. At the same time, in order to obtain the greatest effect caused by the precompression of the reinforcement, certain conditions must be observed.

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