scholarly journals NUMERICAL STUDY OF STRENGTH, FRACTURE TOUGHNESS AND DEFORMATIVNOSTI OF STEEL REINFORCED CONCRETE ELEMENTS OF TRAPEZOIDAL CROSS-SECTION

Author(s):  
Обернихин ◽  
Dmitriy Obernihin

The calculation of fire resistance of reinforced concrete elements depends on the accuracy of the thermal calculation. When performing this calculation, the distribution of the temperature field over the cross section of the element and the strength characteristics that depend on it are determined. The temperature distribution over the section of the structure depends on such parameters as the heat capacity and thermal conductivity of the section parts, and its humidity. The article considers an approach to solving the problem of taking into account the actual temperature field when calculating the fire resistance of reinforced concrete and steel-reinforced concrete elements. Fire resistance calculations were performed for temperature fields that do not take into account the inclusion of reinforcement (concrete section), as well as for temperature fields that take into account temperature inclusions. For the section under consideration, additional coefficients are calculated, which are entered into the calculation of fire resistance when using the method STO 36554501-006-2006 "Rules for ensuring the fire resistance and fire safety of reinforced concrete structures". According to the results of this work, an increase in the bearing capacity of rectangular and square sections was noted when calculating with regard to the thermal characteristics of the reinforcement.


Author(s):  
Olena Yefimenko

In the article presents an engineering method for calculating compressed flexible reinforced concrete elements with sheet reinforcement over a steel cross section. The results of the calculation are compared with the experimental data. Calculation ofload-bearing capacity of reinforced concrete flexible elements with sheet reinforcement is based on the method of boundarystates. The work of specimens under load and the nature of the load-bearing capacity depending on the height and eccentricity of the effort were investigated. The proposed method of calculating compressed elements with sheet reinforcement on asteel-cross-section allows to take into account their flexibility in both axial and out-of-center application of load.


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.


2016 ◽  
Vol 62 (1) ◽  
pp. 65-82 ◽  
Author(s):  
J. Orlowsky

Abstract A large number of infrastructural concrete buildings are protected against aggressive environments by coating systems. The functionality of these coating systems is mainly affected by the composition and thickness of the individual polymeric layers. For the first time ever, a mobile nuclear magnetic resonance (NMR) sensor allows a non-destructive determination of these important parameters on the building site. However, before this technique can be used on steel-reinforced concrete elements, the potential effect of the reinforcement on the measurement, i.e. the NMR signal, needs to be studied. The results show a shift of the NMR profile as well as an increase of the signals amplitude in the case of the reinforced samples, while calculating the thickness of concrete coating leading to identical results.


2020 ◽  
Vol 315 ◽  
pp. 07004
Author(s):  
Dmitry Mailyan ◽  
Alik Blyagoz ◽  
Konstantin Kretinin

The paper contains the issues related to the creation of a non-uniform prestress cross-section of reinforced concrete elements compressed during operation of working with a one-way eccentricity of the resultant longitudinal forces.


2019 ◽  
Vol 23 (7) ◽  
pp. 1290-1304
Author(s):  
Yang Yang ◽  
Ze-Yang Sun ◽  
Gang Wu ◽  
Da-Fu Cao ◽  
Zhi-Qin Zhang

This study presents a design method for hybrid fiber-reinforced-polymer-steel-reinforced concrete beams by an optimized analysis of the cross section. First, the relationships among the energy consumption, the bearing capacity, and the reinforcement ratio are analyzed; then, the parameters of the cross section are determined. Comparisons between the available theoretical and experimental results show that the designed hybrid fiber-reinforced-polymer-steel-reinforced concrete beams with a low area ratio between the fiber-reinforced polymer and the steel reinforcement could meet the required carrying capacity and exhibited high ductility.


2011 ◽  
Vol 243-249 ◽  
pp. 15-19 ◽  
Author(s):  
Zhe Li ◽  
Shao Ji Chen ◽  
Jing Xu ◽  
Ye Ni Wang ◽  
Cui Ping Zhang

Compared with reinforced concrete shaped columns, bearing capacity and ductility of steel reinforced concrete shaped columns are significantly improved, so it is with theoretical significance and practical application of value to research. Based on the plain cross section presume, with material cross-section boundary calculation unit, 15 steel reinforced concrete cross-shaped columns(SRCCSC) have made nonlinear full-rang numerical analysis. It demonstrates that the most adverse curvature ductility load angle of SRCCRSC is 45°.Loading angle (), axial compression ratio (n), and the ratio of spacing and diameter of longitudinal reinforcements (s/d) are the principal factors in curvature ductility of SRCCSC subjected to biaxial eccentric compression. Under the most unfavorable loading angle, through a regression analysis of curvature ductility computer data of 150 cross-shaped columns with 8mm stirrups diameter and 150 columns with 10mm stirrups diameter, it can be obtained with the relationship betweenand axial compression ration,s/d, of SRCCSC subjected to biaxial eccentric compression.


2013 ◽  
Vol 351-352 ◽  
pp. 401-405
Author(s):  
Cheng Zhu Qiu ◽  
Gang Yang

The steel reinforced concrete column is one of the important members for structures, it is essential to study the high temperature performance of concrete column. The numerical simulation research is done using finite element software ANSYS. Under the high temperature, the analysis of the compressive bearing capacity and flexural capacity of the concrete columns strengthened by CFRP is done, and the compressive bearing capacities of different cross-section concrete columns strengthened with CFRP are tested.


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