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.

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.

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.

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 Strengthening with Bonded Steel Angles for Reinforced Concrete Columns after Fire

2013 ◽  
Vol 639-640 ◽  
pp. 1120-1126
Author(s):  
Guo Feng Wang ◽  
Kai Yu ◽  
Jun Hua Li ◽  
Dong Liang Qiu
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Concrete Columns ◽  
Fire Damage ◽  
Tension Zone ◽  
Test Results ◽  
Reinforced Concrete Columns ◽  
Standard Fire ◽  
Eccentric Compression ◽  
Steel Angles

The mechanical properties of fire-damage reinforced concrete columns strengthened with bonded steel angles were studied. Nine specimens were tested, including three normal temperature controlled columns, six heated under ISO834 standard fire. After exposure to fire, three of the six were rehabilitated with the bonded steel angles. It was shown by test results that the destructive properties of reinforced concrete columns with bonded steel angles may change and the small eccentric compression specimens may become large eccentric compression due to the steel angles increased the amount of steel in the tension zone of the specimen. In this research, compared with these under normal temperature, the bearing capacity of specimens which were exposure to fire was only ranged from 0.25 to 0.37 times. But the bearing capacity of specimens rehabilitated by the bonded steel angles can increase to 2.86 to 4.04 times of the originals and it can reach to the level of that in normal temperature.

Experimental Study on Residual Load Bearing Capacity of SRC Eccentric Columns after Exposure to Fire

2010 ◽  
Vol 163-167 ◽  
pp. 2240-2246 ◽  
Author(s):  
Jun Hua Li ◽  
Yue Feng Tang ◽  
Ming Zhe Liu
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Ultimate Strength ◽  
Room Temperature ◽  
Ultimate Load ◽  
Flexural Rigidity ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Steel Reinforced Concrete

This paper provided three test data pertaining to the mechanical properties of steel reinforced concrete (SRC) eccentric columns after exposure to fire and one comparative test data pertaining to the mechanical properties of steel reinforced concrete columns at room temperature. The influence of eccentricity on failure mode, distortion performance and ultimate load bearing capacity are mainly studied. Test results show that the failure modes of steel reinforced concrete eccentric columns after exposure to fire are similar to that at room temperature. Strain along the section height at mid-span section of eccentric columns before loaded to 90% ultimate load bearing capacity is linearly distributed and well agree with the plane section supposition. After exposure to fire, the flexural rigidity and load bearing capacity of specimens are all declined compared with that at normal temperature. In various loading stages from the initial loading to 80% ultimate strength, the ratio of flexural rigidity of SRC eccentric columns after exposure to fire and at normal temperature is ranged from 0.30 to 0.59. With the same concrete strength and heating condition, the ultimate strength of specimens decreases with the increasing of eccentricity. The ultimate bearing capacity of all specimens at normal room temperature is calculated on the method proposed by Chinese regulation JGJ 138-2001. The compared results of experimental values and calculating values show that the residual load bearing capacity of SRC eccentric columns after exposure to fire is about 69% to 81% of that at room temperature.

The Mechanical Properties of FRP Fabric Steel-Reinforced Concrete Columns

2013 ◽  
Vol 815 ◽  
pp. 262-267
Author(s):  
Le Zhou ◽  
Xiao Chu Wang ◽  
Jian Peng Zhang
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Constitutive Relation ◽  
Superposition Principle ◽  
Concrete Columns ◽  
Calculation Formula ◽  
Reinforced Concrete Columns ◽  
Steel Reinforced Concrete ◽  
Correct Formula

The mechanical properties of FRP steel-reinforced concrete columns are discussed. We study the constitutive relation of the concrete, based on the model and the experimental dates for the control the size of affecting parameters. When using the used model, the experimental dates can be reanalyzed and corrected for the intensity correct formula of FRP column. The ultimate bearing capacities of FRP constraint rectangular column use superposition principle to calculate the strength calculation. The ultimate bearing capacity of FRP column is divided into two parts: we conclude the big eccentric bearing capacity calculators formula by the columns bend. Through the study of the column, we concluded that the eccentric loading little eccentric calculation formula of bearing capacity. A case though using the example of this formula is similar with experiments results of the data.

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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