scholarly journals APPROACH TO AN ESTIMATION DEFORMABILITY OF BENDING CONCRETE ELEMENTS BASED ON ITERATIVE CALCULATION METHOD

2016 ◽  
Vol 2 (1) ◽  
pp. 73-76
Author(s):  
Крючков ◽  
Andrey Kryuchkov ◽  
Жданов ◽  
Aleksandr Zhdanov
Keyword(s):  
Reinforced Concrete ◽  
Structural Analysis ◽  
Calculation Method ◽  
Load Bearing Capacity ◽  
Successive Refinement ◽  
Iterative Calculation ◽  
Composite Section ◽  
Initial Stress Method ◽  
Concrete Elements ◽  
Deformation Diagrams

The article deals with existing methods for evaluating the load bearing capacity and deformability of bent reinforced-concrete elements, including the composite section. The analysis of idealized nonlinear dependencies and compressed concrete deformation diagrams. Iterative methods for structural analysis: the method of successive refinement of stiffness, the method of successive loadings, initial stress method. Results of their algorithms and shows the advantage of using the method of the dual stiffness are considered.

Improving the Methodology for Calculating the Bearing Capacity of Eccentrically Compressed Reinforced Concrete Elements Based on the Use of the Refined Curvilinear Deformation Diagrams of Concrete and Reinforcement

2019 ◽  
Vol 974 ◽  
pp. 570-576
Author(s):  
Alexander I. Nikulin ◽  
Al-Khawaf Ali Fadhil Qasim
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Linear Equations ◽  
Resistance Force ◽  
Deformation Model ◽  
Concrete Element ◽  
Element Determination ◽  
Numerical Studies ◽  
Concrete Elements ◽  
Deformation Diagrams

The article proposes a new approach to improving the methodology for calculating the bearing capacity of the eccentrically compressed reinforced concrete elements for cases of their loading with large eccentricities. The basis of this technique is considered as a modified version of the deformation model for the reinforced concrete resistance force. The main feature of this model is the energy approach to transforming the reference diagrams of compression and concrete tension into the diagrams of non-uniform deformation, corresponding to the stress-strain state of the compressed and stretched zones of concrete in the cross section of the eccentrically compressed reinforced concrete structures. This way there is no falling branch in the concrete diagrams obtained by this method. A calculation diagram of the steel reinforcement deformation with a physical yield point was taken as a partial function, consisting of one linear and two non-linear equations. The proposed method also shows the possibility of taking into account the greatest curvature of an eccentrically compressed reinforced concrete element in the plane of its loading. The article presents all the necessary dependencies allowing the theoretical value of the carrying capacity of an eccentrically compressed reinforced concrete element determination. The results of the numerical studies performed using the design software developed by the authors for the personal computer are given.

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.

Strength of Normal and Inclined Sections of Bent Reinforced Concrete Elements with Zone Reinforcement Made of Steel Fiber

2022 ◽  
Vol 906 ◽  
pp. 7-15
Author(s):  
Dmitry Utkin
Keyword(s):  
Reinforced Concrete ◽  
Dynamic Loading ◽  
Calculation Method ◽  
Steel Fiber ◽  
Experimental Studies ◽  
Concrete Structures ◽  
Dynamic Loads ◽  
Reinforced Concrete Structures ◽  
Short Term ◽  
Concrete Elements

On the basis of theoretical and experimental studies, the prerequisites and the method of calculation of bent and compressed-curved reinforced concrete structures with zone reinforcement made of steel fiber, working under static and short-term dynamic loads, are formulated. In the developed method for calculating the strength of normal and inclined sections, a nonlinear deformation model is implemented, which is based on the actual deformation diagrams of materials. The developed calculation method is brought to the program of calculation of reinforced concrete structures with zone reinforcement of steel fiber under short-term dynamic loading, taking into account the inelastic properties of materials. The numerical studies made it possible to determine the influence of various parameters of steel-fiber reinforcement on the strength of reinforced concrete elements. To confirm the main results of the developed calculation method, experimental studies of reinforced concrete beam structures reinforced with conventional reinforcement and a zone steel-fiber layer are planned and carried out. Experimental studies were carried out under static and short-term dynamic loads. As a result of the conducted experiments, data were obtained that characterize the process of destruction, deformation and cracking of steel-reinforced concrete elements under such types of loading. The dependences of changes in the energy intensity of reinforced concrete structures with zone reinforcement made of steel fiber in the compressed and stretched cross-section zones under dynamic loading are obtained. The effectiveness of the use of fiber reinforcement of normal and inclined sections of bent and compressed-curved elements to improve the strength and deformative.

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.

scholarly journals CAPACITY FLEXIBLE COMPRESSED REINFORCED CONCRETE ELEMENTS REINFORCED WITH STEEL SHEETS

2018 ◽  
Vol 1 (50) ◽  
pp. 79-87
Author(s):  
L. I. Storozhenko ◽  
S. O. Murza ◽  
О. І. Yefimenko
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Carrying Capacity ◽  
Applied Load ◽  
Experimental Studies ◽  
Load Bearing Capacity ◽  
Steel Reinforced Concrete ◽  
Steel Sheets ◽  
Dependence Graphs ◽  
Concrete Elements

The experimental studies results of reinforced concrete elements with sheet reinforcement load bearing capacity are presented. The drawing of experimental designs is shown. The bearing capacity dependence graphs of the tested steel-reinforced concrete samples with sheet reinforcement on the height of the element and dependence graphs of tested steel-reinforced concrete samples with sheet reinforcement carrying capacity on the applied eccentricity are constructed. The photo shows the destruction character of experimental steel-concrete samples with sheet reinforcement depending on their height. The general schedule of bearing capacity dependence on the height of the element and the eccentricity of the applied load is constructed.

scholarly journals Methods of Calculation the Increased Reinforced Concrete Elements by Carrying Capacity of Slope Sections

2021 ◽  
Vol 1203 (2) ◽  
pp. 022051
Author(s):  
Andrii Mazurak ◽  
Roman Kinasz ◽  
Ivan Kovalyk ◽  
Rostyslav Mazurak ◽  
Vitaliy Kalchenko
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Experimental Studies ◽  
Longitudinal Axis ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Theoretical Approaches ◽  
Reinforced Beams ◽  
Eurocode 2 ◽  
Concrete Elements

Abstract Reinforcement bending reinforced concrete structures by increasing the cross section and assessing the load-bearing capacity of the inclined section such elements is an urgent problem, as not yet accumulated adequate research data on the stress-strain state such structures in the span, which works on shear and shear bending moment and transverse force. Analyzing the development theories calculation reinforced concrete elements inclined to the longitudinal axis, we can identify many areas, the main approach of which was based on the calculation using the bases of material resistance, and the use of empirical dependencies. Theoretical approaches calculation the European construction magazine RILEM TC, SNiP 2.03.01.-84* are considered, DBN B.2.6-98 2009 (Eurocode 2), US ACI 318-19. Experimental studies reinforced concrete elements to determine the load-bearing capacity inclined sections were performed on the basis of 5 samples reinforced concrete beams, 14 reinforced samples of reinforced concrete and shotcrete a total of 19 pieces in four series. Beams were made of concrete in each series fck = 19.08 MPa; fck = 27.74 MPa; fck = 20.48 MPa; fck = 20.48 MPa, respectively, reinforced samples with concrete fck = 17.95 MPa; fck = 19.5 MPa (shotcrete fck = 31.00 MPa); shotcrete fck = 19.9 MPa; fck = 19.9 MPa. Also for the manufacture and reinforcement beams used flat and U-shaped frames with working longitudinal reinforcement Ø22, Ø16, Ø12, Ø10, Ø6 A400C, and transverse reinforcement Ø6 A240C (step 120 mm). Reinforcement inclined sections of the experimental beams was performed on one, two or three sides, depending on the variant of the sample and the type of frame flat or U-shaped. Investigations of beams were performed according to the static scheme - a beam on two supports, span L=2100 mm. Deformations of concrete and reinforcement in the samples when determining the bearing capacity of inclined sections were measured using microindicators of the clock type, strain gauges. According to the results theoretical and experimental studies the bearing capacity inclined sections to the longitudinal axis, we can see a significant reassessment between the theoretical values inclined sections according to the new DBN B.2.6.-98: 2009 (Eurocode 2) over the actual results obtained during testing samples 53-67% for conventional beams, and 27-50% for reinforced beams. The results US regulations ACI 318-19 showed convergence of results in the range of 2-9% for samples without reinforcement and 1-7% for samples with reinforcement, but the values show the excess of experimental data over theoretical, indicating the impossibility of accurately determining the actual final bearing capacity. The results the calculation obtained by the method of SNiP 2.03.01-84*, both unreinforced and reinforced beams has a satisfactory agreement with the experimental values in the range of 6-10%.

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.

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