scholarly journals An experimental study on variability of deformation characteristics of concrete in compression

Vestnik MGSU ◽  
2020 ◽  
pp. 1390-1398
Author(s):  
Mixail G. Plyusnin ◽  
Sergey V. Tsybakin
Keyword(s):  
Experimental Study ◽  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Cross Section ◽  
Strength Analysis ◽  
Deformation Model ◽  
Deformation Characteristics ◽  
Concrete Element ◽  
Linear Deformation ◽  
Concrete Elements

Introduction. An experimental study on variability of deformation characteristics of concrete and an assessment of its influence on the bearing capacity of eccentrically compressed reinforced concrete elements were performed. In pursuance of effective regulatory documents, a non-linear deformation model was applied to perform the strength analysis of standard cross sections of reinforced concrete structures. The application of this method in probabilistic design is also of interest. Analytical functions approximating the true σ–ε diagram, made for concrete, use strength and deformation characteristics of concrete as parameters. However, variability of deformation characteristics of concrete has not been sufficiently studied, although it may have significant influence on results of analyses. Materials and methods. Complete σ–ε diagrams were made for uniaxially compressed concrete to solve this problem. These diagrams were applied to numerically assess the influence of variability of deformation characteristics of concrete on the bearing capacity of an eccentrically compressed reinforced concrete element in terms of its standard cross section. A non-linear deformation model was used to identify the bearing capacity. Results. The experiment has proven substantial variation of diagram shapes within the same strength class. The influence of the εb0 value of ultimate deformations of concrete on the bearing capacity is demonstrated for a standard cross section as a result of the strength analysis of an eccentrically compressed reinforced concrete element. The strength analysis was performed by applying experimental σ–ε diagrams made for uniaxially compressed concrete. Conclusions. The analysis of the findings has shown that the value of ultimate deformations of concrete exposed to uniaxial compression affects the bearing capacity of eccentrically compressed reinforced concrete elements. The degree of influence depends on concrete strength, reinforcement percentage and the eccentricity of a longitudinal force.

Improving the Methodology for Calculating the Bearing Capacity of Eccentrically Compressed Reinforced Concrete Elements Based on the Use of the Refined Curvilinear Deformation Diagrams of Concrete and Reinforcement

2019 ◽  
Vol 974 ◽  
pp. 570-576
Author(s):  
Alexander I. Nikulin ◽  
Al-Khawaf Ali Fadhil Qasim
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Linear Equations ◽  
Resistance Force ◽  
Deformation Model ◽  
Concrete Element ◽  
Element Determination ◽  
Numerical Studies ◽  
Concrete Elements ◽  
Deformation Diagrams

The article proposes a new approach to improving the methodology for calculating the bearing capacity of the eccentrically compressed reinforced concrete elements for cases of their loading with large eccentricities. The basis of this technique is considered as a modified version of the deformation model for the reinforced concrete resistance force. The main feature of this model is the energy approach to transforming the reference diagrams of compression and concrete tension into the diagrams of non-uniform deformation, corresponding to the stress-strain state of the compressed and stretched zones of concrete in the cross section of the eccentrically compressed reinforced concrete structures. This way there is no falling branch in the concrete diagrams obtained by this method. A calculation diagram of the steel reinforcement deformation with a physical yield point was taken as a partial function, consisting of one linear and two non-linear equations. The proposed method also shows the possibility of taking into account the greatest curvature of an eccentrically compressed reinforced concrete element in the plane of its loading. The article presents all the necessary dependencies allowing the theoretical value of the carrying capacity of an eccentrically compressed reinforced concrete element determination. The results of the numerical studies performed using the design software developed by the authors for the personal computer are given.

Evaluation Of The Effect Of Eccentricity Of Longitudinal Force On The Provision Of Bearing Capacity Of Compressed Concrete Elements

2019 ◽  
pp. 29-34 ◽  
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Coefficient Of Variation ◽  
Longitudinal Force ◽  
Deformation Model ◽  
Concrete Element ◽  
Average Value ◽  
Strength And Deformation ◽  
The Given ◽  
Concrete Elements

This work evaluates the influence of the eccentricity of longitudinal force on the provision of the bearing capacity of an eccentrically compressed reinforced concrete element in the normal section at different percentages of longitudinal reinforcement. The nonlinear deformation model was used for probabilistic calculations, which made it possible to take into account the influence of strength and deformation characteristics of concrete on the bearing capacity of the elements of reinforced concrete structures. The dependences of the relative average value of the maximum longitudinal force and the coefficient of variation for the given percent of reinforcement on the eccentricity of the longitudinal force are obtained. The significant influence of the value of the longitudinal force eccentricity on the coefficient of variation of the bearing capacity of the eccentrically compressed concrete element in the normal cross section is shown. It is noted that the revealed dependence of the bearing capacity of eccentrically compressed reinforced concrete elements on the eccentricity of the longitudinal force is not taken into account in the existing methods of calculation.

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.

Experimental Study on Reinforcement of Failure Reinforced Concrete Beams

2013 ◽  
Vol 275-277 ◽  
pp. 1264-1267
Author(s):  
Qian Chen ◽  
Ling Yong Liu ◽  
Yang Jun Meng
Keyword(s):  
Experimental Study ◽  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Epoxy Resin ◽  
Cross Section ◽  
Concrete Beams ◽  
Experimental Results ◽  
Reinforced Concrete Beams ◽  
Carbon Cloth ◽  
Structural Failure

Through repair and reinforcement of breaking reinforced concrete beams by epoxy resin and carbon cloth, and its experiment, the crack and deformation and bearing capacity as well as ductility of such beams are obtained. Experimental results show that the ultimate bearing capacity of beams after reinforcement increased by 210%, the structure ductility fell by 170%, structural failure form is similar to failure in normal cross section.

Improvement of Regulatory Calculation of the Load-Carrying Capacity of Vibrated, Centrifuged, and Vibrocentrifuged-Based Iron-Concrete Columns with Variatropic Structure

2020 ◽  
pp. 78-84
Author(s):  
Л. Р. Маилян ◽  
С. А. Стельмах ◽  
Е. М. Щербань ◽  
А. А. Чернильник
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
Carrying Capacity ◽  
Concrete Columns ◽  
Strength Analysis ◽  
Load Carrying Capacity ◽  
Load Bearing Capacity ◽  
Load Carrying ◽  
Regulatory Approach ◽  
Concrete Elements

Состояние проблемы. Сжатые железобетонные элементы изготавливаются 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 соответствует действительности лишь в вибрированных колоннах. Результаты. Разработан усовершенствованный нормативный подход к расчету прочности центрифугированных и виброцентрифугированных железобетонных колонн, заключающийся в использовании в расчете интегральных или дифференциальных характеристик бетона. Выводы. Расчет прочности коротких центрально сжатых вибрированных, центрифугированных и виброцентрифугированных колонн по усовершенствованному нормативному подходу дал наилучшие результаты с использованием дифференциальных характеристик бетона, различающихся по сечению. Statement of the problem. Compressed reinforced concrete elements are manufactured according to three main technologies - vibrating, centrifuging and vibrocentrifugation. However, all the main calculated dependences for determining their load-bearing capacity were derived based on the main postulate - the constancy and equality of the characteristics of concrete over the cross section, which corresponds to reality only in vibrated columns. Results. An improved regulatory approach has been developed for calculating the strength of centrifuged and vibrocentrifuged reinforced concrete columns, which involves using the calculation of integral or differential characteristics of concrete. Conclusions. Strength analysis of short centrally compressed vibrated, centrifuged and vibrocentrifuged columns using an improved regulatory approach yielded the best results using differential characteristics of concrete varying in cross section.

Experimental Study on the Influence of Slab’s Reinforcement on Seismic Bearing Capacity of Beam’s Cross-Section in Cast-In Situ Frame Structure

2013 ◽  
Vol 353-356 ◽  
pp. 1986-1989
Author(s):  
Jin Shi Guo ◽  
Xin Ying Xie
Keyword(s):  
Experimental Study ◽  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Cross Section ◽  
Engineering Application ◽  
Frame Structure ◽  
Reinforced Concrete Frame ◽  
Concrete Frame ◽  
Frame Work ◽  
Seismic Bearing Capacity

“strong beam and weak column”is the main failure states of reinforced concrete frame structure in the earthquake．This paper is the experimental study of the influence on the virtual cross-section bearing capacity on extremity of frame beam in reinforced concrete，which is affected by some element，such as slab reinforcement，the rigidity of orthogonal beam and so on．Exploring the mechanism of slab and frame work together to determine the width of effective flange，which provides references for structural design and engineering application．

scholarly journals HISTORY OF THE APPEARANCE OF EULER’S FORMULA. ISSUES OF STABILITY OF COMPRESSED REINFORCED CONCRETE ELEMENTS

2021 ◽  
Vol 11 (1) ◽  
pp. 18-25
Author(s):  
Sergey S. MORDOVSKIY ◽  
Anna A. KISELEVA
Keyword(s):  
Reinforced Concrete ◽  
High Strength Concrete ◽  
High Strength ◽  
Deformation Model ◽  
Reinforced Concrete Structures ◽  
Linear Deformation ◽  
History Of ◽  
Life Path ◽  
Concrete Elements ◽  
Concrete Hardening

The article presents a brief overview of the life path of the Swiss mathematician and mechanic Leonard Euler, considers the history of the emergence of the formula for calculating stability, shows options for taking into account the fl exibility of an element in the calculations of reinforced concrete structures, the disadvantages of the Euler curve and the features of its application in relation to structures made of high-strength concrete and concrete hardening under pressure. An example of the result of using a non-linear deformation model in the calculations of eccentrically compressed reinforced concrete elements with the introduction into the algorithm for calculating a coeffi cient that takes into account the eff ect of buckling (defl ection) of an element on its bearing capacity is given.

Experimental Study on Reinforcement of Failure Reinforced Concrete Beams

2014 ◽  
Vol 578-579 ◽  
pp. 1266-1270
Author(s):  
Qiang Chen ◽  
Ling Yong Liu ◽  
Yang Jun Meng
Keyword(s):  
Experimental Study ◽  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Epoxy Resin ◽  
Cross Section ◽  
Concrete Beams ◽  
Experimental Results ◽  
Reinforced Concrete Beams ◽  
Carbon Cloth ◽  
Structural Failure

Through repair and reinforcement of breaking reinforced concrete beams by epoxy resin and carbon cloth, and its experiment, the crack and deformation and bearing capacity as well as ductility of such beams are obtained. Experimental results show that the ultimate bearing capacity of beams after reinforcement increased by 210%, the structure ductility fell by 170%, structural failure form is similar to failure in normal cross section.

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