EXPERIMENTAL INVESTIGATION ON STRENGTHENING OF REINFORCED CONCRETE COLUMNS WITH CARBON CONCRETE COMPOSITE

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Klaus Holschemacher ◽  
Dennis Messerer ◽  
Wladislaw Polienko
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fiber ◽  
Bearing Capacity ◽  
Cross Sections ◽  
Concrete Columns ◽  
Experimental Program ◽  
Load Bearing Capacity ◽  
Reinforced Concrete Columns ◽  
Load Bearing ◽  
Concrete Members

The application of textile reinforced concrete is well-approved technique for strengthening of reinforced concrete members. When using carbon fiber meshes and carbon fiber reinforced polymer bars as reinforcement, this material is called carbon concrete composite. Based on the outstanding properties of carbon fibers, carbon concrete composite is characterized by high bending and tensile strength, and good durability. Therefore, carbon concrete composite is increasingly applied as replacement for ordinary steel bar or steel mesh reinforced concrete. It is favorable building material for production of new buildings and for strengthening of existing reinforced concrete members. In the context of strengthening of existing reinforced concrete columns, it is a usual procedure to cover the member’s surface with a thin layer of carbon concrete composite aiming on reduction of lateral strains of the core concrete when load is increasing. The result is an increased load-bearing capacity of the strengthened column. However, there is insufficient knowledge about the influence of curvature of the carbon meshes in circular cross-sections and in the corners of rectangular cross-sections on their load-bearing capacity. For this reason, an experimental program started to study the influence of curvature, number and type of mesh layers and specimen dimensions on structural behavior of strengthened columns under axial loading. As main outcome it can be stated that besides the curvature other parameters like yarn properties are of essential importance.

Experimental Study on the Mechanical Properties of Reinforced Concrete Columns after Exposure to Fire

2011 ◽  
Vol 243-249 ◽  
pp. 5122-5127
Author(s):  
Jia Feng Xu ◽  
Ming Zhe Liu ◽  
Yue Feng Tang
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Failure Mode ◽  
Room Temperature ◽  
Ultimate Load ◽  
Concrete Columns ◽  
Load Bearing Capacity ◽  
Reinforced Concrete Columns ◽  
Load Bearing

This paper provided three test data pertaining to the mechanical properties of reinforced concrete columns after exposure to ISO834 standard fire and three comparative test data pertaining to the mechanical properties of reinforced concrete columns at room temperature, mainly concerning the influence of fire on failure mode, distortion performance and ultimate load bearing capacity of reinforced concrete columns under axial and eccentric compression. Test results show that the failure mode of reinforced concrete columns after exposure to fire is basically same with that at room temperature. With the same concrete strength and heating condition, the bearing capacity of specimens reduces as the eccentricity increases. Strain along the section height of eccentric columns after fire basically agree with the plane section supposition while the flexural rigidity and ultimate load bearing capacity decreases obviously. The residual load bearing capacity of reinforced concrete columns after exposure to fire is only about 25% to 37% of that at room temperature.

Research on the Mechanical Properties of Fire-Damaged Reinforced Concrete Columns Strengthened with CFRP

2012 ◽  
Vol 193-194 ◽  
pp. 1429-1435
Author(s):  
Dong Liang Qiu ◽  
Kai Yu ◽  
Guo Feng Wang ◽  
Jun Hua Li
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Temperature Control ◽  
Concrete Columns ◽  
Load Bearing Capacity ◽  
Reinforced Concrete Columns ◽  
Load Bearing ◽  
Standard Fire ◽  
Reinforced Polymer

The mechanical properties of fire-damaged reinforced concrete columns rehabilitated by carbon fiber-reinforced polymer (CFRP) rods were studied. This study aims at the effectiveness of CFRP through the contrast test. Nine specimens were tested, including three normal temperature control specimens, and six specimens heated under ISO834 standard fire. After the specimens were exposed to fire, three of them were rehabilitated by CFRP. All specimens were loaded monotonically to failure in the same way. The results showed that the failure of reinforced concrete columns rehabilitated by CFRP was due to losing stabilization, whereas the others were material broken. Furthermore, because of the fire, the load-bearing capacity of specimens was all declined sharply compared with these at normal temperature. From this research, comparing with these normal temperature control specimens, the load-bearing capacity of specimens exposed to fire firstly was ranged from 0.25 to 0.37 times. But the ratio of the loading capacity of specimens rehabilitated by CFRP and normal temperature control ones was ranged from 0.54 to 0.67.

Behavior of GFRP Strengthened Reinforced Concrete Columns under Large Eccentric Compression Load

2012 ◽  
Vol 446-449 ◽  
pp. 311-317
Author(s):  
Ji Zhong Wang ◽  
Yong Feng Wang ◽  
Su Yan Wang
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Concrete Columns ◽  
Load Bearing Capacity ◽  
Reinforced Concrete Columns ◽  
Load Bearing ◽  
Compression Load ◽  
Eccentric Compression ◽  
Test Result

This paper compares three standards of FRP strengthened concrete columns published by ACI committee, Concrete Society and China respectively. A test is designed according to the comparison. A total of five columns were cast and tested. The analysis of the load bearing capacity and ductility of the test result indicates that wrapping hoop GFRP can enhance load bearing capacity slightly and the ductility greatly, wrapping axial GFRP can enhance load bearing capacity greatly but the failure of column is brittle, wrapping axial GFRP over-wrapped with hoop GFRP can both enhance load bearing capacity and the ductility.

scholarly journals Load Bearing Capacity Calculation of the System “Reinforced Concrete Beam – Deformable Base” under Torsion with Bending

2019 ◽  
Vol 97 ◽  
pp. 04059 ◽  
Author(s):  
Alexey Dem’yanov ◽  
Vladymir Kolchunov ◽  
Igor Iakovenko ◽  
Anastasiya Kozarez
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Cross Sections ◽  
Concrete Beam ◽  
Equations Of State ◽  
Reinforced Concrete Beam ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Deformable Base ◽  
The Relationship

It is presented the formulation and solution of the load bearing capacity of statically indeterminable systems “reinforced concrete beam – deformable base” by spatial cross-sections under force and deformation effects. The solution of problem is currently practically absent in general form. It has been established the relationship between stresses and strains of compressed concrete and tensile reinforcement in the form of diagrams. The properties of the base model connections are described based on a variable rigidity coefficient. It is constructed a system of n equations in the form of the initial parameters method with using the modules of the force (strain) action vector. The equations of state are the dependences that establish the relationship between displacements which are acting on the beam with load. Constants of integration are determined by recurrent formulas. It makes possible to obtain the method of initial parameters in the expanded form and, consequently, the method of displacements for calculating statically indefinable systems. The values of the effort obtained could be used to determine the curvature and rigidity of the sections in this way. It is necessary not to set the vector modulusP, the deformation is set in any section (the module is considered as an unknown) during the problem is solving. This allows us to obtain an unambiguous solution even in the case when the dependence M–χ has a downward section, i.e one value of moment can correspond to two values of curvature.

Carbon Fiber Strips Retrofitting System for Precast Reinforced Concrete Wall Panel

2015 ◽  
Vol 660 ◽  
pp. 208-212 ◽  
Author(s):  
Mihai Fofiu ◽  
Andrei Bindean ◽  
Valeriu Stoian
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fiber ◽  
Bearing Capacity ◽  
Maximum Load ◽  
Fiber Reinforced Polymers ◽  
Wall Panel ◽  
Concrete Wall ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Reinforced Concrete Wall

This paper presents the retrofitting procedure used on a precast reinforced concrete wall panel (PRCWP) in order to restore its initial load bearing capacity. The specimen used in this experimental test is one from the residential multistoried buildings constructed in Romania from the 1970 onwards. All of the characteristics of the element are from the specific era, only scaled down with a factor of 1:1,2. The element was subjected to in-plane reversed cyclic loading to simulate its seismic behavior and obtain its maximum load bearing capacity. After the test we retrofitted the element using Carbon Fiber Strips Externally Bonded (EBR) and anchored with Carbon Fiber Reinforced Polymers (CFRP) mesh. The porpoise of the paper is to compare the maximum loading bearing capacity of the unstrengthen and strengthen elements in order to compare them and examine the efficiency of this retrofitting procedure.

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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