Experimental Study of Corroded RC Beams Strengthened with CFRP under Fatigue and Monotonic Loads

2011 ◽  
Vol 243-249 ◽  
pp. 142-148
Author(s):  
Lei Wang ◽  
Jin Xiu Liang
Keyword(s):  
Experimental Study ◽  
Reinforced Concrete ◽  
Composite Laminates ◽  
Load Capacity ◽  
Experimental Studies ◽  
Corrosion Damage ◽  
Fatigue Loading ◽  
Reinforced Concrete Beams ◽  
Ultimate Load Capacity ◽  
Cfrp Composite

This paper summarizes the results and discussion of experimental studies on corroded, reinforced concrete 4 point beam test specimens (120 mm x 200 mm x 1700 mm) repaired by external bonding of carbon fiber reinforced polymer (CFRP) composite laminates to the tensile face of the beam. The primary parameters investigated in this experimental study were distortion, stress distribution, and ultimate load capacity of the corroded reinforced concrete beams. The results indicate that the load capacity and the rigidity of repaired corroded beams by CFRP were significantly higher than the un-repaired, corroded beams. Beams with a low degree of corrosion damage, repaired by CFRP, were still able to demonstrate good mechanical properties after a short-term fatigue loading.

Performance of Reinforced Concrete Beams with Multiple Openings

2020 ◽  
Vol 857 ◽  
pp. 162-168
Author(s):  
Haidar Abdul Wahid Khalaf ◽  
Amer Farouk Izzet
Keyword(s):  
Reinforced Concrete ◽  
Ultimate Load ◽  
Concrete Beams ◽  
Load Capacity ◽  
Reinforced Concrete Beams ◽  
Design Parameters ◽  
Ultimate Load Capacity ◽  
Concentrated Load ◽  
Simply Supported ◽  
Group I

The present investigation focuses on the response of simply supported reinforced concrete rectangular-section beams with multiple openings of different sizes, numbers, and geometrical configurations. The advantages of the reinforcement concrete beams with multiple opening are mainly, practical benefit including decreasing the floor heights due to passage of the utilities through the beam rather than the passage beneath it, and constructional benefit that includes the reduction of the self-weight of structure resulting due to the reduction of the dead load that achieves economic design. To optimize beam self-weight with its ultimate resistance capacity, ten reinforced concrete beams having a length, width, and depth of 2700, 100, and 400 mm, respectively were fabricated and tested as simply supported beams under one incremental concentrated load at mid-span until failure. The design parameters were the configuration and size of openings. Three main groups categorized experimental beams comprise the same area of openings and steel reinforcement details but differ in configurations. Three different shapes of openings were considered, mainly, rectangular, parallelogram, and circular. The experimental results indicate that, the beams with circular openings more efficient than the other configurations in ultimate load capacity and beams stiffness whereas, the beams with parallelogram openings were better than the beams with rectangular openings. Commonly, it was observed that the reduction in ultimate load capacity, for beams of group I, II, and III compared to the reference solid beam ranged between (75 to 93%), (65 to 93%), and (70 to 79%) respectively.

scholarly journals Post-strengthening of reinforced concrete beams with prestressed CFRP strips. Part 1: analysis under static loading

2012 ◽  
Vol 5 (3) ◽  
pp. 343-361
Author(s):  
M. R. Garcez ◽  
G. L. C. P. Silva Filho ◽  
Urs Meier
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Load Capacity ◽  
Experimental Studies ◽  
Reinforced Concrete Beams ◽  
Experimental Program ◽  
Existing Structures ◽  
Flexural Tests ◽  
Strengthening Technique ◽  
Epoxy Matrices

Different FPR post-strengthening techniques have been developed and applied in existing structures aiming to increase their load capacity. Most of the FRP systems used nowadays consist of carbon fibers embedded in epoxy matrices (CFRP). Regardless of the advantages and the good results shown by the CFRP post-strengthen technique, experimental studies show that, in most cases, the failure of post-strengthened structures is premature. Aiming to better use the tensile strength of the carbon fiber strips used as post-strengthening material, the application of prestressed CFRP strips started to be investigated. The main purpose of this paper is to analyze the effects of the composite prestressing in the performance of the CFRP post strengthening technique. The experimental program was based on flexural tests on post-strengthened reinforced concrete beams subjected to static - part 1 and cyclic - part 2 loading. Experimental results allowed the analysis of the quality and shortcomings of post-strengthen system studied, which resulted in valuable considerations about the analyzed post-strengthened beams.

Shear Strengthening of Reinforced Concrete Beams with HFRP Composite

2016 ◽  
Vol 860 ◽  
pp. 152-155
Author(s):  
Sanyawit Siriluk ◽  
Qudeer Hussain ◽  
Winyu Rattanapitikon ◽  
Amorn Pimanmas
Keyword(s):  
Reinforced Concrete ◽  
Ultimate Load ◽  
Natural Fiber ◽  
Load Capacity ◽  
Reinforced Concrete Beams ◽  
Deep Beam ◽  
Fiber Layer ◽  
Ultimate Load Capacity ◽  
Shear Strengthening ◽  
Hemp Fiber

This paper presents an experimental study on the strengthening of scaled reinforced concrete (RC) deep beam using hemp fiber reinforced polymer (HFRP) composite. HFRP is the composite material which compose of hemp fiber bonding with epoxy resin. The major benefit of using hemp fiber is that their low price, high toughness, and hemp is natural fiber product which that can be found locally. In this study 2 different fiber orientation has been apply to scaled deep beam and also different in thickness (fiber layer). Three scaled deep beam were strengthened using HFRP composite, remaining one beam was tested as control (unstrengthen) beam. The test result show that HFRP composite are effective to enhance ultimate load capacity for RC beam. The HFRP composite applied in U-Shape was result into higher ultimate load compare with the sample that applied with both side strengthen method

scholarly journals EXPERIMENTAL STUDIES OF THE KINETICS OF THE DEVELOPMENTAL CORROSIVE DAMAGES OF CONCRETE IN BENT REINFORCED CONCRETE ELEMENTS UNDER FORCE AND ENVIRONMENTAL EFFECTS

2020 ◽  
pp. 34-43
Author(s):  
N. Frolov
Keyword(s):  
Reinforced Concrete ◽  
Prolonged Exposure ◽  
Experimental Studies ◽  
Corrosion Damage ◽  
Reinforced Concrete Beams ◽  
Damage Development ◽  
Normative Documents ◽  
Concrete Corrosion ◽  
Adopted Model ◽  
Kinetics Of

The article deals with the main aspects of the development of concrete corrosion damage in reinforced concrete structures. It is noted that the main quantitative indicators of such damages are the depth and the damage factor. Their change in time characterizes the kinetics of the development of concrete corrosion damage. The kinetic model of corrosion damage development by V.M. Bondarenko is presented as perspective for inclusion into normative documents. For the purpose of its additional substantiation special experimental studies of loaded samples of reinforced concrete beams and non-loaded samples in the form of concrete cubes and prisms under prolonged exposure to sulfate- and chloride-containing aggressive media have been conducted. New experimental data on peculiarities of accumulation of corrosive damages of concrete taking into account the influence of different operational factors have been obtained. It is established that damage development has a pronounced fading character over time and depends on the type of operating medium, the presence of cracks, the sign and level of stresses acting in the concrete. In case of sulfate corrosion, the damage coefficient of the outer layer of concrete in the transition zone does not take into account the value equal to zero. It is concluded that the adopted model quite reliably describes the development of corrosive damages of concrete in these corrosive environment.

scholarly journals Investigating Some Parameters Affecting Flexural Behaviour of Reinforced Concrete Beams Strengthened with CFRP Laminate

2018 ◽  
Vol 2 (5) ◽  
Author(s):  
Azad A. Mohammed
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Load Capacity ◽  
Reinforced Concrete Beams ◽  
Flexural Behaviour ◽  
Ultimate Load Capacity ◽  
Cfrp Laminate ◽  
Steel Rebar ◽  
Effective Depth ◽  
Strengthened Beam

In this paper, the influence of some important parameters affecting flexural behaviour of reinforced concrete beams strengthened with one layer of CFRP laminate has been studied. For this purpose, six reinforced concrete beams were cast and tested in the laboratory. Based on the obtained data, when CFRP laminate is applied to the tension face, too close to the steel rebar, the flexural strength of the strengthened beam is reduced. In general, the performance of the beam strengthened with one wide CFRP strip is better than that strengthened with two equivalent narrow strips. Ultimate load capacity of each strengthened beam was calculated based on the method given by the ACI 440.2R and compared with the test one. It is concluded that to avoid the steel rebar-CFRP laminate interaction effect, the CFRP laminate depth to the effective depth ratio (df / d) should not be smaller than about 1.17.

scholarly journals Post-strengthening of reinforced concrete beams with prestressed CFRP strips: part 2: analysis under cyclic loading

2012 ◽  
Vol 5 (4) ◽  
pp. 420-439
Author(s):  
M. R. Garcez ◽  
L. C. P. Silva Filho ◽  
Urs Meier
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Load Capacity ◽  
Experimental Studies ◽  
Reinforced Concrete Beams ◽  
Experimental Program ◽  
Existing Structures ◽  
Flexural Tests ◽  
Strengthening Technique ◽  
Epoxy Matrices

Different FPR post-strengthening techniques have been developed and applied in existing structures aiming to increase their load capacity. Most of the FRP systems used nowadays consist of carbon fibers embedded in epoxy matrices (CFRP). Regardless of the advantages and the good results shown by the CFRP post-strengthen technique, experimental studies show that, in most cases, the failure of post-strengthened structures is premature. Aiming to better use the tensile strength of the carbon fiber strips used as post-strengthening material, the application of prestressed CFRP strips started to be investigated. The main purpose of this paper is to analyze the effects of the composite prestressing in the performance of the CFRP post strengthening technique. The experimental program was based on flexural tests on post-strengthened reinforced concrete beams subjected to static - part 1 and cyclic - part 2 loading. Experimental results allowed the analysis of the quality and shortcomings of post-strengthen system studied, which resulted in valuable considerations about the analyzed post-strengthened beams.

Experimental Studies on the Mechanical Performances of Corroded Reinforced Concrete Columns Retrofitted with FRP

2013 ◽  
Vol 405-408 ◽  
pp. 726-730 ◽  
Author(s):  
Ying Wu Zhou ◽  
Ling Yi Wu ◽  
Li Li Sui ◽  
Feng Xing
Keyword(s):  
Experimental Study ◽  
Reinforced Concrete ◽  
Load Capacity ◽  
Experimental Studies ◽  
Concrete Columns ◽  
High Corrosion Resistance ◽  
Rc Columns ◽  
Corrosion Rates ◽  
Externally Bonded ◽  
Mechanical Performances

Due to the superiority of high corrosion resistance of FRP materials, more and more attentions have been attracted to the retrofitting of corroded reinforced concrete (RC) columns with FRP. This paper thus presents an experimental study on mechanical performances of corroded RC columns strengthened with FRP, focusing on the effects of different corrosion rates of the reinforcements and the retrofitting scheme. The effectiveness of externally bonded FRP to the corroded RC column to increase its load capacity and ductility is tested; the mechanical performances of the strengthened columns are theoretically investigated. The results indicate that the effectiveness of retrofitting the existing corroded RC columns with FRP jackets is much more significant than that of retrofitting the newly built columns with FRP jackets and externally wrapped with FRP jackets is much more effective to improving the structural performances of heavily corroded columns.

Experimental Study of Section Enlargement with Reinforced Concrete to Increase Shear Capacity for Damaged Reinforced Concrete Beams

2012 ◽  
Vol 256-259 ◽  
pp. 1148-1153 ◽  
Author(s):  
Yuan Dong Wang ◽  
Shen Yang ◽  
Miao Han ◽  
Xun Yang
Keyword(s):  
Reinforced Concrete ◽  
Epoxy Resin ◽  
Cross Section ◽  
Load Capacity ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Second Phase ◽  
Ultimate Shear Strength ◽  
Ultimate Load Capacity ◽  
External Reinforcement

This paper presents the results of reinforced concrete (RC) beams strengthened in shear by external reinforcement with RC or epoxy resin mortar. The test specimen was 2000mm long with a cross section of 150mm×200mm and after section enlargement the cross section was increased to 250mm×300mm, in addition, shear span to beam depth ratio of a/h0 was 2.35. All specimens had the same geometry and were distinguished by the configurations of stirrup which was the primary test variable. No shear reinforcement was provided in the first phase of test, while in the second phase external RC or epoxy resin mortar was provided to enable failure due to shear. Experiments are undertaken to investigate the influence of preexisting damage, configurations of stirrup and different methods on the strengthened behavior and mode of failure. A group unstrengthened control beams were tested and failed in shear. In contrast to the control beam, all of the strengthened beams showed a significant improvement in their ultimate load capacity when they were failing in shear. The enlarged section with reinforced concrete can significantly increase the ductility and ultimate shear strength of a concrete beam. The method of section enlargement with RC is a high effective technique to enhance shear ability. An analysis for shear strengthening of beams using external reinforcement with RC has also been carried out as well.

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