Estimation of Load Bearing Capacity of Eccentrically Compressed Reinforced Concrete Elements under Dynamic Loading in Fire Conditions

2014 ◽  
Vol 638-640 ◽  
pp. 62-65 ◽  
Author(s):  
Ashot Tamrazyan ◽  
Levon Avetisyan
Keyword(s):  
Reinforced Concrete ◽  
Dynamic Loading ◽  
Analytical Calculation ◽  
Dynamic Strength ◽  
Concrete Columns ◽  
Dynamic Coefficient ◽  
Load Bearing Capacity ◽  
In Fire ◽  
Concrete Elements ◽  
Fire Conditions

Research of influence of fire impacts on the dynamic strength of eccentrically compressed concrete elements requires a deeper consideration. The purpose of this article is the study of dynamic strength of eccentrically compressed concrete elements in fire conditions under rapidly increasing dynamic loading. It is done the analytical calculation of eccentrically compressed reinforced concrete columns under different thermo powers conditions, there are shown the results of calculations and experimental data. It is shown a graph of dynamic coefficient for concrete depending on the time of dynamic loading and temperature.

Reduce the Impact of Dynamic Strength of Concrete under Fire Conditions on Bearing Capacity of Reinforced Concrete Columns

2013 ◽  
Vol 475-476 ◽  
pp. 1563-1566 ◽  
Author(s):  
Ashot Tamrazyan
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Dynamic Strength ◽  
Dynamic Effect ◽  
Concrete Columns ◽  
Fire Effects ◽  
Dynamic Loads ◽  
Dynamic Coefficient ◽  
The Impact ◽  
Concrete Elements

This article provides an example of the calculation of eccentrically compressed reinforced concrete elements operating under dynamic loads and fire effects. Dynamic coefficient depending on temperature and strain rate, the results of experiment varies widely from 0.4 to 0.8. It is possible to reveal the influence of the dynamic effect on the reduction of the bearing capacity of the pylon and fire and columns of 40%.

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.

Evaluation of the Compressed Reinforced Concrete Elements Dynamic Strength, Taking into Account the Temperature Influence on the Strength and Deformability of Reinforcement Steel and Concrete

2018 ◽  
Vol 931 ◽  
pp. 334-339
Author(s):  
Levon A. Avetisyan ◽  
Mikhail V. Danilov
Keyword(s):  
Reinforced Concrete ◽  
Dynamic Stiffness ◽  
Experimental Studies ◽  
Dynamic Strength ◽  
Concrete Element ◽  
Internal Forces ◽  
The Moment ◽  
Increasing Temperature ◽  
In Fire ◽  
Concrete Elements

In the article the results of the eccentrically compressed reinforced concrete element calculation operating under the dynamic loading in fire conditions are shown. The calculation of the compressed reinforced concrete element was carried out, taking into account the conducted experimental studies. The calculation showed that, depending on the temperature effects, the curvature of the reinforced concrete element in stages I and II decreases while the class concrete, which varies from 28.9% to 55%, is increasing. When the temperature reaches 2500, the cracking moment and the moment of internal forces at the end of the stage II are reduced to 22% with respect to these forces at normal conditions. With increasing temperature, the dynamic stiffness of the element in the stage I is reduced by 29.3%.

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.

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.

Using of Plastic Hinges in the Calculation of Buildings against Progressive Collapse under Fire Exposure

2018 ◽  
Vol 878 ◽  
pp. 115-120
Author(s):  
Levon Avetisyan
Keyword(s):  
Reinforced Concrete ◽  
Progressive Collapse ◽  
Experimental Studies ◽  
Fire Exposure ◽  
Reinforced Concrete Frame ◽  
Dynamic Calculation ◽  
Plastic Hinges ◽  
Concrete Frame ◽  
In Fire ◽  
Concrete Elements

This article presents a study of the strength of a 25-storey reinforced concrete frame against progressive collapse in fire conditions. Taking into account the angles of disclosure of plastic hinges as norming for the strength of reinforced concrete elements, a computer technology program has been developed and included in PR Wolfram Mathematica 10 for the dynamic calculation of compressed reinforced concrete elements under fire exposure on the basis of the conducted experimental studies. Dynamic calculation of the strength of eccentrically compressed reinforced concrete columns was carried out, with operation in normal conditions and under high temperatures. The diagram «moment-curvature» and the graph of the change of the static and dynamic strength of the column depending on the temperature were developed. Nonlinear dynamic analysis of a 25-storey reinforced concrete frame was conducted, taking into account the changes of the dynamic characteristics of reinforced concrete elements in fire and, the estimation of resistance of the frame was given.

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