scholarly journals Strength of eccentrically tensioned reinforced concrete structures with small eccentricities by normal sections

2021 ◽  
Vol 30 (3) ◽  
pp. 424-438
Author(s):  
Yevhen Dmytrenko ◽  
Oleg Fesenko ◽  
Ihor Yakovenko
Keyword(s):  
Reinforced Concrete ◽  
Complete Disappearance ◽  
Gradual Change ◽  
Software Complex ◽  
Internal Forces ◽  
External Forces ◽  
The Given ◽  
Concrete Elements ◽  
Considerable Loss ◽  
Central Tension

It is implemented the method of normal rectangular sections slab (shell) reinforced concrete elements strength calculating with flat eccentric tensile strength using the deformation m ethod. The results of the calculation are analyzed for the case of eccentric tension with small eccentricities with varying next parameters: the height of the cross section and the reinforcement coefficient. It is investigated the character of diagrams condition change of section “N – εc(1)” at gradual change of the stress-strain state from eccentric to the central tension. It is revealed that when the eccentricity of external forces decreases, the compressed zone of concrete decreases until its complete disappearance, and at rather small values of eccentricities of force application the balance between external and internal forces cannot be found by the method of current norms. An equilibrium is found between internal and external forces only at a two-digit diagram of the distribution of relative longitudinal deformations (in the case of a compressed zone). Variants of the given problem decision without considerable loss of calculations accuracy are offered, the most expedient of which is transition to algorithm of calculation by a method of limiting efforts. It was accepted as the basic in the previous building norms. The results of numerical calculations performed in the software complex “Lira-CAD” and the corresponding mathematical modeling confirmed the rationality and allowable accuracy of further calculations by this method.

scholarly journals Strength and deformability of reinforced concrete elements under oblique eccentric short-term dynamic compression, tension and bending

2020 ◽  
Vol 164 ◽  
pp. 14008
Author(s):  
Dmitriy Sarkisov ◽  
Nikolay Gorlenko ◽  
Gleb Gorynin ◽  
Yuri Sarkisov ◽  
Gafurzhan Izmailov ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Crack Resistance ◽  
Dynamic Compression ◽  
Longitudinal Force ◽  
Research Data ◽  
Deformation Model ◽  
Relative Resistance ◽  
Short Term ◽  
Concrete Elements ◽  
Central Tension

The paper deals with research data of reinforced concrete rectangular and I-shaped cross-section elements, operating under oblique eccentric short-term dynamic compression, tension and bending. The method of reinforced concrete elements calculation using the theory of surfaces of relative resistance regarding strength and crack resistance is suggested. It is based on the deformation model with the use of real nonlinear diagrams of concrete and reinforcement. This method makes it possible to observe strength and crack resistance of reinforced concrete elements sections in the entire range of loadings from the central tension to axial compression. Experimental investigation of symmetrically reinforced concrete elements on oblique eccentric short-term dynamic compression, tension and oblique bending was carried out. Effect of longitudinal force level on strain distribution through the depth of section, bearing capacity, the failure scheme and other parameters are estimated.

scholarly journals ESSENTIALS AND PROBLEMS SOLVING ALGORITHMS OF GENERAL STRENGTH THEORY OF RC ELEMENTS UNDER COMPLEX STRESS-STRAIN STATES

2018 ◽  
Vol 1 (50) ◽  
pp. 104-111
Author(s):  
V. P. Mitrofanov ◽  
N. M. Pinchuk N.M.
Keyword(s):  
Reinforced Concrete ◽  
Experimental Verification ◽  
Economic Effect ◽  
Complex Stress ◽  
Strength Theory ◽  
Software Complex ◽  
Manual Method ◽  
Concrete Elements ◽  
Lateral Reinforcement ◽  
Selection Of

The General strength theory of reinforced concrete elements (GSTRCE) passed the long and many-sided examination and showed the considerable advantages: well concordance with experiments, essential economic effect, solving method unity for different strength problems. Simple practical methods for calculating according to GSTRCE and available for use by designers and students are developed. The algorithms of calculating of two practically important problems are stated: strength control and selection of needed longitudinal and lateral reinforcement. Problems solving are represented by using «manual» method and well-known and easy-to-use software complex MS Excel. The results of experimental verification of GSTRCE are stated and the ones show well convergence of theoretical strength to experimental one.

The Concrete Diagrams Integral Parameters in the Calculations of Reinforced Concrete Elements by Limiting States

2019 ◽  
Vol 974 ◽  
pp. 698-703
Author(s):  
Valeriy A. Eryshev
Keyword(s):  
Reinforced Concrete ◽  
Neutral Axis ◽  
Stress Profile ◽  
Deformation Model ◽  
Gravity Center ◽  
Stress Diagram ◽  
Internal Forces ◽  
Concrete Elements ◽  
Deformation Diagrams ◽  
Base Diagrams

The paper proposes a method for calculating the reinforced concrete elements strength according to the deformation model using the deformation diagrams of concrete and reinforcing steel materials, which eliminates the complicated procedure of numerical integration of stresses in the element section during the transition to generalized internal forces. Integral parameters of diagrams are introduced into the energy model for calculating the strength of reinforced concrete elements along with the deformations and stresses normalized values at the base diagrams’ points. The integral parameters are calculated for the element cross section, the strain at the stress diagram gravity center in the compressed concrete zone and the coordinates of force in the concrete and reinforcement are relative to the neutral axis from the condition of the stress profile shape compliance in the element compressed zone, and the concrete diagram is used in the calculations. The integral parameters calculated dependences for the compressive strength concrete classes. The recommendations on the concrete diagrams integral parameters values rationing and their use in the complex sections and statically indeterminable systems calculations are given.

Calculation Of Pressure Of Reinforcement Corrosion Products In Reinforced Concrete Element

2019 ◽  
pp. 65-69
Keyword(s):  
Reinforced Concrete ◽  
Protective Layer ◽  
Corrosion Products ◽  
Reinforcement Corrosion ◽  
Concrete Element ◽  
Geometric Nonlinearities ◽  
Good Convergence ◽  
Software Complex ◽  
Scientific Papers ◽  
Concrete Elements

The existing regulatory framework does not cover the calculation of reinforced concrete elements subjected to corrosion. The calculation of such elements is given in a number of scientific papers. The article deals with a particular problem of calculation-finding the pressure of corrosion products and calculation of detachment of the protective layer. To solve this problem, the polar-symmetric problem was solved and formulas for determining the pressure of corrosion products, stresses and displacements were obtained. The condition of destruction of samples is received based on the theory of strength of G. A. Geniev. The calculations carried out on the obtained dependences have good convergence with the calculations taking into account the physical and geometric nonlinearities, performed in the universal software complex ABAQUS. An engineering method for calculating the separation of the protective layer was developed. The possibility of experimental confirmation of the calculations, as well as the need for additional research in the field of corrosion damages is shown.

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.

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%.

Stress-strain state of corrosion-damaged reinforced concrete elements under dynamic loading

2019 ◽  
pp. 19-26
Keyword(s):  
Reinforced Concrete ◽  
Strain State ◽  
Concrete Beam ◽  
Reinforced Concrete Beam ◽  
Stress Strain ◽  
Static Loads ◽  
Software Complex ◽  
Stress Strain State ◽  
The Impact ◽  
Concrete Elements

The solution of problems of survivability of reinforced concrete elements at beyond design impacts caused by simultaneous manifestation of power and environmental factors is necessary in modern realities. The impact of external aggressive environments, the operation of buildings without timely repairs is the cause of corrosion processes in reinforced concrete elements, which leads to a decrease in their bearing capacity and, as a consequence, reduction in the life of buildings. Currently, one of the urgent problems is the actual work of corrosion-damaged reinforced concrete elements under the impact of dynamic and static loads. The bendable reinforced concrete beam locally damaged in the compressed part of the cross-section is considered. Using modern computing software complex, it was carried out the comparative evaluation of the stress-strain state of an undamaged and corrosion-damaged reinforced concrete elements under dynamic and static loading. The influence of the weakened by corrosion concrete part of the compressed area on the redistribution of stresses in the section is analyzed.

Error Analysis in Calculating the Internal Force of Plane Statically Determinate Truss by the Original Size Principle

2012 ◽  
Vol 268-270 ◽  
pp. 1168-1171
Author(s):  
Dan Ma ◽  
Yan Dong Qu ◽  
Xiang Qing Kong
Keyword(s):  
Internal Force ◽  
Calculation Error ◽  
Size Principle ◽  
Tensile Stiffness ◽  
Mechanics Of Materials ◽  
Internal Forces ◽  
Original Size ◽  
External Forces ◽  
The Given ◽  
Small Deformations

Ignoring the deformation effect, the original size principle is normally used to calculate the internal force and deformations of the bars in Mechanics of Materials, the calculation error is not discussed in the textbooks, however. In order to show the adaptability of the original size principle to calculate the internal force of plane statically determinate truss, a case of the two-bar statically determinate truss was also given. The calculation error of the internal force and the angle deformations are quantitatively studied to make a comparison between the actual internal force and that calculated by the original size principle. The research showed that the relative error of angle deformations and the internal forces of the two rods are nonlinear dependent on the external forces (the given force), tensile stiffness and the initial angle of the plane truss. If the strength and tensile stiffness of the bars can meet the requirements of engineering, the original size principle can be used to calculate the internal force of metallic bar truss under the conditions of small deformations.

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.

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