Experimental Researches of Concrete Ultimate Characteristics and Strength of Compressed and Bended Reinforced Concrete Elements

2020 ◽  
pp. 133-141
Author(s):  
Dmytro Lazariev ◽  
Yurii Avramenko ◽  
Oleksandr Zyma ◽  
Pavlo Pasichnyk
Keyword(s):  
Reinforced Concrete ◽  
Experimental Researches ◽  
Concrete Elements

scholarly journals THE EXPERIMENTAL RESEARCHES OF REINFORCED CONCRETE I-BEAM ELEMENTS WITH NORMAL CRACKS WHEN TURNING

2019 ◽  
Vol 2 (53) ◽  
pp. 171-176
Author(s):  
Olga Orlova
Keyword(s):  
Reinforced Concrete ◽  
Twist Angle ◽  
Longitudinal Reinforcement ◽  
External Torque ◽  
Beam Elements ◽  
The Difference ◽  
The Moment ◽  
Nonlinear Deformations ◽  
Experimental Researches ◽  
Concrete Elements

The data of experimental researches of the rigidity of reinforced concrete I-beam elements with normal cracks at the action on them of the twisting moment have resulted in this paper. It is shown that the dependence "torque-twist angle" is almost linear. Significant nonlinear deformations appear in the last stages of loading before failure. Therefore at normative torques, it is recommended to consider the work of reinforced concrete elements of the I-beam cross-section with normal cracks linear. It is shown that the presence of longitudinal reinforcement affects the strength and rigidity of beams with normal cracks. Quite a large part of the external torque is perceived by the pin forces in the longitudinal reinforcement. The difference between the external torque and the moment of the pin forces in the armature is perceived by the upper shelf of the I-beam element. In the absence of longitudinal reinforcement, the upper shelf can collapse at loads much smaller than the destructive load of beams with longitudinal reinforcement.

scholarly journals The technology of experimental researches of the strength of bent reinforced concrete elements in the zone of action of transverse forces

2021 ◽  
Author(s):  
I.N. Starishko
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Cross Section ◽  
Steel Reinforcement ◽  
Inclined Crack ◽  
Shear Span ◽  
Depth Analysis ◽  
The Cross ◽  
Experimental Researches ◽  
Concrete Elements

Extensive experimental researches of the author of the article showed that in T-profile beams, despite the fact that with an increase in the length of the shear span, the bearing capacity along inclined sections significantly decreases, the effect of overhangs of compressed flanges on the bearing capacity of these beams, on the contrary, increases, and when, with an increase in the length of the shear span, the beam becomes equal in strength in normal and inclined sections, the effect of overhangs, as a rule, becomes the same in both the strength of normal and the strength of inclined sections, which is not taken into account in the regulatory documents of Russia, the USA and a number of other countries. At the same time, experiments have shown that the smaller the rib width in the cross section of bent reinforced concrete T-profile beams (standard beams of bridge structures on the territory of Russia), the greater the effect of the overhangs of compressed flanges on their bearing capacity along inclined sections. The values of the influences on the bearing capacity of bent reinforced concrete elements of such factors as: the forces of engagement of the rough surface of the banks when they are displaced in an inclined crack from the action of the load; the nagel effect in the longitudinal steel reinforcement at the intersection of it with an inclined crack; prestressing in longitudinal steel reinforcement, depending on the amount of transverse steel reinforcement and the width of the cross-section of the elements, etc. The technology for conducting experimental researches will have a positive effect for the development of a reliable theory for calculating bent reinforced concrete elements along inclined sections only when it includes the whole complex of a variety of the influence of the main factors on the operation of the researched elements with its in-depth analysis.

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 Application of artificial neural networks to predict the deflections of reinforced concrete beams

2016 ◽  
Vol 38 (2) ◽  
pp. 37-46 ◽  
Author(s):  
Mateusz Kaczmarek ◽  
Agnieszka Szymańska
Keyword(s):  
Neural Network ◽  
Neural Networks ◽  
Artificial Neural Network ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
The Neural Network ◽  
Eurocode 2 ◽  
Artificial Neural ◽  
Concrete Elements

Abstract Nonlinear structural mechanics should be taken into account in the practical design of reinforced concrete structures. Cracking is one of the major sources of nonlinearity. Description of deflection of reinforced concrete elements is a computational problem, mainly because of the difficulties in modelling the nonlinear stress-strain relationship of concrete and steel. In design practise, in accordance with technical rules (e.g., Eurocode 2), a simplified approach for reinforced concrete is used, but the results of simplified calculations differ from the results of experimental studies. Artificial neural network is a versatile modelling tool capable of making predictions of values that are difficult to obtain in numerical analysis. This paper describes the creation and operation of a neural network for making predictions of deflections of reinforced concrete beams at different load levels. In order to obtain a database of results, that is necessary for training and testing the neural network, a research on measurement of deflections in reinforced concrete beams was conducted by the authors in the Certified Research Laboratory of the Building Engineering Institute at Wrocław University of Science and Technology. The use of artificial neural networks is an innovation and an alternative to traditional methods of solving the problem of calculating the deflections of reinforced concrete elements. The results show the effectiveness of using artificial neural network for predicting the deflection of reinforced concrete beams, compared with the results of calculations conducted in accordance with Eurocode 2. The neural network model presented in this paper can acquire new data and be used for further analysis, with availability of more research results.

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