Proposals for Determining the Relative Deformations Design Value of εb3 Concrete in Volumetric Deformation Conditions

2021 ◽  
Vol 1043 ◽  
pp. 155-162
Author(s):  
Sergey Georgiev ◽  
Dmitriy Mailyan ◽  
Alik Blyagoz
Keyword(s):  
Experimental Data ◽  
Reinforced Concrete ◽  
Composite Materials ◽  
Transverse Direction ◽  
Calculation Methodology ◽  
Calculation Results ◽  
Russian Norms ◽  
Concrete Elements ◽  
Significant Underestimation ◽  
Composite Reinforcement

The article presents the studies’ results on the deformability and strength of reinforced concrete racks reinforced with composite materials with the characteristics stretching beyond the limits established by the norms of Russia, namely: the λh structures flexibility exceeding the value 15, the ratio of the cross-section sides equal to 1.5 and the eccentricity of the load application e0 exceeding 0.1h. The results of the tested racks calculations are analyzed according to BC 164.1325800.2014, which in some cases confirmed the inexpediency of using composite materials. However, according to the results of our experiment, an increase in the strength of a number of racks with the characteristics that go beyond the recommended standards was found. The purpose of this study is to check the methodology for calculating Russian norms for the compressed reinforced concrete elements, the parameters of which are outside the limits recommended by the norms, to develop proposals for improving the calculation based on the obtained experimental data and to determine the concrete deformability effect on the change in bearing capacity. The article discusses flexible struts, reinforced with composite materials, located in the transverse direction. The experimental data results on the deformability of concrete and the strength of struts reinforced in the transverse direction are presented. The calculation methodology, compiled in accordance with Russian standards, the calculation results of which are the theoretical values ​​of the deformability of concrete and the strength of the racks, is considered. After comparison, a significant underestimation of the theoretical strengths and a mismatch in the struts’ concrete deformations were revealed. It was found that the change in compressive deformations of concrete depends on the external composite reinforcement. Theoretical values , calculated according to the current standards, have significant discrepancies with the experimental ones. Based on the experiments’ results analysis, in the methodology of norms for calculating the ultimate compressive deformations of concrete the suggestions that take into account the type and percentage of composite reinforcement and ensure a good agreement between experimental and theoretical values have been made. After the introduction of the coefficient into normative calculation, new data on the theoretical strength of the struts were obtained, which showed significantly better convergence with the experimental data.

scholarly journals To Calculation Of Bended Elements Working Under The Conditions Of Exposure To High And High Temperatures On The Lateral Force By A New Method

2021 ◽  
Vol 03 (05) ◽  
pp. 210-218
Author(s):  
Makhkamov Yuldashali Mamazhonovich ◽  
◽  
Mirzababayeva Sahiba Mirzaakbarovna ◽  
Keyword(s):  
Experimental Data ◽  
Reinforced Concrete ◽  
High Temperatures ◽  
Calculation Method ◽  
Lateral Force ◽  
New Method ◽  
Design Standards ◽  
Current Design ◽  
Calculation Results ◽  
Concrete Elements

The article presents a new method for calculating bending reinforced concrete elements made of conventional and heat-resistant concrete operating under conditions of high and high technological temperatures on the action of transverse forces. The advantage of the proposed calculation method over the method adopted in the current design standards based on a comparison of the calculation results of the experimental data is shown.

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.

Tests on Mechanical Properties and Anti-Penetration Performance of Steel-Fiber Reactive Powder Concrete

2013 ◽  
Vol 671-674 ◽  
pp. 1761-1765
Author(s):  
Yong Liu ◽  
Chun Ming Song ◽  
Song Lin Yue
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Compressive Strength ◽  
Reinforced Concrete ◽  
Steel Fiber ◽  
Reactive Powder Concrete ◽  
Calculation Results ◽  
Reactive Powder ◽  
Penetration Tests

In order to get mechanical properties ,some RPC samples with 5% steel fiber are tested, many groups data were obtained such as compressive strength, shear strength and fracture toughness. And a group of tests on RPC with 5% steel-fiber under penetration were also conducted to validate the performance to impact. The penetration tests are carried out by the semi-AP projectiles with the diameter of 57 mm and earth penetrators with the diameter of 80 mm, and velocities of the two kinds of projectiles are 300～600 m/s and 800～900 m/s, respectively. By contrast between the experimental data and the calculation results of C30 reinforced concrete by using experiential formula under penetration, it shows that the resistance of steel-fiber RPC to penetration is 3 times as that of general C30 reinforced concrete.

scholarly journals Optimizing of system "column-cfrp lamellas" with the strengthening of civil structures

2021 ◽  
Vol 9 (1) ◽  
pp. 1-5
Author(s):  
Irina Mayackaya ◽  
Batyr Yazyev ◽  
Anastasia Fedchenko ◽  
Denis Demchenko
Keyword(s):  
Reinforced Concrete ◽  
Composite Materials ◽  
Carbon Fiber ◽  
Concrete Structures ◽  
Polymeric Composite ◽  
Concrete Columns ◽  
Reinforced Concrete Structures ◽  
Structural Elements ◽  
Civil Structures ◽  
Concrete Elements

Reinforced concrete elements of structures in the form of columns, beams, ceilings are widely used in the construction of buildings and structures of industrial and civil construction. In most cases, the columns serve as supports for other building elements, for example, crossbars, slabs, girders, beams. One of the cycles of the work of reinforced concrete structures is the state of their repair and reconstruction, including the stages of strengthening the elements. There is a problem of strengthening of reinforced concrete columns. The article deals with the issue of reinforcing columns and other structural elements having a cylindrical surface, with polymeric composite materials in the form of carbon fiber lamellae. The use of composite materials allows to increase the service life and strength of reinforced concrete structures used in construction.

scholarly journals Numerical and experimental studies of bent elements of basalt fiber reinforced concrete with prestressed glass composite reinforcement under static and short-term dynamic loads

2019 ◽  
Vol 221 ◽  
pp. 01026
Author(s):  
Vasilii Plevkov ◽  
Konstantin Kudyakov
Keyword(s):  
Reinforced Concrete ◽  
Experimental Studies ◽  
Basalt Fiber ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Dynamic Effects ◽  
Glass Composite ◽  
Short Term ◽  
Concrete Elements ◽  
Composite Reinforcement

The article shows studies of bending basalt fiber reinforced concrete elements with pre-stressed glass composite reinforcement under static and short-term dynamic effects. Main results of numerical and experimental studies are presented. It is experimentally established and theoretically confirmed that a significant increase in the strength and crack resistance of the normal sections of concrete bent elements is observed when using basalt fiber reinforcement and pre-stressed glass composite reinforcement.

scholarly journals An integrated approach to the use of composite materials for the restoration of reinforced concrete structures

2019 ◽  
Vol 135 ◽  
pp. 03068 ◽  
Author(s):  
Vladimir Rimshin ◽  
Pavel Truntov
Keyword(s):  
Reinforced Concrete ◽  
Composite Materials ◽  
Bearing Capacity ◽  
Concrete Structures ◽  
Integrated Approach ◽  
Reinforced Concrete Structures ◽  
Technical Inspection ◽  
Concrete Layer ◽  
External Reinforcement ◽  
Calculation Results

The article presents the results of a technical inspection of the state of the structures of the object. To conduct the study, horizontal structures of the sludge pool that were exposed to the carbonization reaction were taken for the objects under investigation. Defects and damages of the considered structures revealed during visual inspection are described. The degree of carbonization of reinforced concrete structures was determined by the phenolphthalein sample method. According to the results of the technical inspection, a verification calculation of the beam was carried out in order to determine its bearing capacity for assessing the suitability for further operation after restoration and strengthening. The calculation was performed using software. Based on the calculation results, data on the bearing capacity of the beam reinforced with composite materials were determined. The option of restoring and strengthening the beam using external reinforcement based on carbon fibers FibArm 230/150 is presented. The restoration was carried out taking into account the carbonized concrete layer. Based on the results of the study, an assessment is given of the application of an integrated approach to the restoration and strengthening of structures with composite materials, taking into account the carbonized concrete layer.

scholarly journals THE INFLUENCE OF SHEAR SPAN RATIO ON LOAD CAPACITY OF FIBRE REINFORCED CONCRETE ELEMENTS WITH VARIOUS STEEL FIBRE VOLUMES

2007 ◽  
Vol 13 (3) ◽  
pp. 209-215 ◽  
Author(s):  
Remigijus Šalna ◽  
Gediminas Marčiukaitis
Keyword(s):  
Experimental Data ◽  
Reinforced Concrete ◽  
Steel Fibre ◽  
Load Capacity ◽  
Fibre Volume ◽  
Fibre Reinforced Concrete ◽  
Test Results ◽  
Shear Span ◽  
Concrete Elements ◽  
Empirical Approaches

This paper analyses the influence of steel fibre volume and shear span ratio on the strength of fibre reinforced concrete elements in various states of stress. 36 beams with three different shear spans (a/h = 1, 1,5, and 2 %) and three different fibre volumes (1, 1,5, and 2 %) were tested to examine how these factors influence the behaviour of such elements. Test results suggest that steel fibre volume and shear span can increase load capacity, plasticity and cracking. Experimental research showed that steel fibre volume has different influence at different shear span ratios. Regression analysis of experimental data was carried out and empirical approach showing different effect of these factors was proposed. Furthermore, test results were compared with different theoretical and empirical approaches of other authors.

scholarly journals Operational durability of reinforced concrete structures

2019 ◽  
Vol 91 ◽  
pp. 02012 ◽  
Author(s):  
Mikhail Berlinov ◽  
Marina Berlinova ◽  
Artem Grigorjan
Keyword(s):  
Experimental Data ◽  
Reinforced Concrete ◽  
Probabilistic Model ◽  
Probabilistic Models ◽  
Corrosion Damage ◽  
Reinforced Concrete Structures ◽  
Structural Elements ◽  
Kinetics Of Degradation ◽  
Concrete Elements ◽  
Kinetics Of

The resistance properties of reinforced concrete and reinforcement, required for modeling the degradation and calculations of the durability of reinforced concrete elements under the conditions of various types of corrosion damage, based on analytical and experimental data are substantiated. A probabilistic model has been developed for predicting and estimating the durability and reliability of reinforced concrete elements, taking into account the statistical variability of the calculation parameters and the kinetics of degradation processes during long periods of operation. Methods are proposed for calculating and predicting the durability of reinforced concrete elements based on deterministic probabilistic models of degradation of structural elements operating under aggressive environmental influences.

Sign in / Sign up

Export Citation Format

Share Document