Plasticity Theory in Strength Calculations Concrete Elements Under Local Compression

2021 ◽  
pp. 343-353
Author(s):  
Volodymyr Pohribnyi ◽  
Oksana Dovzhenko ◽  
Oleksiy Fenko ◽  
Dmytro Usenko
2018 ◽  
Vol 230 ◽  
pp. 02005 ◽  
Author(s):  
Oksana Dovzhenko ◽  
Volodymyr Pohribnyi ◽  
Volodymyr Pents ◽  
Dmytro Mariukha

The necessity of creating a general methodology for concrete and reinforced concrete elements strength calculation under the shear is established. Three failure cases of reinforced concrete corbels under the shear are considered. The solutions of problems of corbels strength with failure along the whole section, close to the normal, in the compressed zone under an inclined crack and within the compressed inclined strip are given. A variational method in the plasticity theory, the virtual velocities principle and the characteristic lines method are used for concrete and reinforced concrete elements calculations. In the ultimate state, concrete is considered as a rigid-plastic body. The shear is realized in case when the plastic deformation is localized in the compressed zone. The calculating ultimate load results for different failure cases are given. Such a design scheme is implemented, in which the console strength is minimal. This corresponds to the minimum of power of plastic deformation in concrete compressed zone. Reinforced concrete corbels calculation engineering methods are offered. The elements obtaining effective constructive decisions direction based on the plasticity theory use is determined.


Author(s):  
Оksana Dovzhenko ◽  
Volodymyr Pohribnyi ◽  
Оlena Maliovana ◽  
Leonid Karabash

Application boundaries of the truss analogy and disk model methods to the strength calculation of reinforced concrete flexuralelements inclined sections are established. Areas of structures failure by virtual compressed element (inclined strip) andcompressed zone over dangerous inclined crack under the shear force are determined. The criterion of minimum limit force,which is perceived by the elements, is applied. Influence of concrete class, relative shear span and transverse reinforcementintensity on elements strength based on variational method in plasticity theory is specified. The data concerning the values ofthe transverse reinforcement coefficient at the boundaries of the failure from shear within the inclined strip and compressedzone over the dangerous crack are obtained.


2017 ◽  
Vol 116 ◽  
pp. 02026 ◽  
Author(s):  
Volodymyr Pohribnyi ◽  
Oksana Dovzhenko ◽  
Leonid Karabash ◽  
Iryna Usenko

Author(s):  
Л. Р. Маилян ◽  
С. А. Стельмах ◽  
Е. М. Щербань ◽  
М. П. Нажуев

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.


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