scholarly journals Experimental study on flexural behaviour of reinforced concrete beams strengthened with passive and active CFRP strips using a novel anchorage system

2022 ◽  
Vol 22 (1) ◽  
Author(s):  
Bartosz Piątek ◽  
Tomasz Siwowski
Keyword(s):  
Tensile Strength ◽  
Reinforced Concrete ◽  
Full Range ◽  
Positive Influence ◽  
Reinforced Concrete Beams ◽  
The Novel ◽  
Rc Beams ◽  
Flexural Behaviour ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer

AbstractThe paper presents the research on reinforced concrete (RC) beams strengthened with carbon fibre reinforced polymer (CFRP) strips with various configurations in terms of anchoring and tensioning. The five full-scale RC beams with the total length of 6.0 m were strengthened with passive strips, without and with mechanical anchorages at their ends, as well as with strips tensioned by the novel prestressing system with three various prestressing levels ranging from 30 to 50% of the CFRP tensile strength. All RC beams were tested under static flexural load up to failure and they were investigated in a full range of flexural behaviour, including the post-debonding phase. The main parameters considered in this study include the use of mechanical anchorages, the effect of tensioning the strips and the influence of the various prestressing levels. Several performance indicators have been established to evaluate the beams’ behaviour. The study revealed that the RC beams strengthened using tensioned CFRP strips exhibited a higher cracking, yielding and ultimate moments as compared to the beams with passively bonded CFRP strips. Moreover, increasing the beams’ prestressing level has a significant positive influence on the performance of strengthened beams. However, it did not affect the ultimate load-bearing capacity of the beams. The optimal prestressing level for the novel system has been determined as 60% of CFRP tensile strength.

scholarly journals Static Analysis of Reinforced Concrete Beams Strengthened with CFRP Composites/ Analiza Statyczna Belek Zelbetowych Wzmocnionych Tasmami Kompozytowymi

2010 ◽  
Vol 56 (2) ◽  
pp. 111-122 ◽  
Author(s):  
W. Głodkowska ◽  
M. Ruchwa
Keyword(s):  
Reinforced Concrete ◽  
Static Analysis ◽  
Concrete Beams ◽  
Full Range ◽  
Physical Nonlinearity ◽  
Calculation Model ◽  
Reinforced Concrete Beams ◽  
Reinforced Concrete Structure ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer

Abstract This paper presents the possibility to apply numerical simulation in static analysis of reinforced concrete structure strengthened with carbon fibre reinforced polymer composite strips (CFRP). Reinforced concrete beams, with strengthening in form values CFRP made of carbon fibres and epoxy resin, featuring various width, as well as non-strengthened bent beams, were analysed. The simply supported beams arranged in a free support scheme were subjected to two concentrated forces within full range of loading (until collapse). The numerical analysis was performed through application of the Finite Elements Method (FEM), and the calculation model applied took into account the geometric and physical nonlinearity. The problem was solved by application of the quasi-static strategy method of calculations using ABAQUS software. While analysing the results, we focused on the run of changes in structure displacement and development of material damage, up to the point of destruction of the beam

Behaviour of reinforced GFRP bars concrete beams having strengthened splices using CFRP sheets

2021 ◽  
pp. 136943322110015
Author(s):  
Akram S. Mahmoud ◽  
Ziadoon M. Ali
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
New Method ◽  
Gfrp Bars ◽  
Reinforced Polymer ◽  
Strength Capacity ◽  
Cfrp Sheet ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer

When glass fibre-reinforced polymer (GFRP) bar splices are used in reinforced concrete sections, they affect the structural performance in two different ways: through the stress concentration in the section, and through the configuration of the GFRP–concrete bond. This study experimentally investigated a new method for increasing the bond strength of a GFRP lap (two GFRP bars connected together) using a carbon fibre-reinforced polymer (CFRP) sheet coated in epoxy resin. A new splicing method was investigated to quantify the effect of the bar surface bond on the development length, with reinforced concrete beams cast with laps in the concrete reinforcing bars at a known bending span length. Specimens were tested in four-point flexure tests to assess the strength capacity and failure mode. The results were summarised and compared within a standard lap made according to the ACI 318 specifications. The new method for splicing was more efficient for GFRP splice laps than the standard lap method. It could also be used for head-to-head reinforcement bar splices with the appropriate CFRP lapping sheets.

FINITE ELEMENT MODELLING OF 2-SPAN CONTINUOUS RC BEAMS SHEAR STRENGTHENED AND SHEAR REPAIRED WITH CFRP STRIPS

2016 ◽  
Vol 78 (5) ◽  
Author(s):  
Abdul Aziz Abdul Samad ◽  
Noorwirdawati Ali ◽  
Noridah Mohamad ◽  
J. Jayaprakash ◽  
Tuan Duc Ngo ◽  
...  
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Shear Behaviour ◽  
Rc Beams ◽  
Shear Strengthening ◽  
Existing Structures ◽  
Finite Element Software ◽  
Externally Bonded ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer

Strengthening of reinforced concrete (RC) continuous beams in shear have received very little attention among researchers even though most existing structures are in the form of continuous condition such as part of a floor-beam system. Therefore, in order to address the gap, a study on shear strengthening and shear repair of reinforced concrete continuous beam using Carbon Fibre Reinforced Polymer (CFRP) strips was conducted [15].  The validation of the experimental results was conducted with a simulation study using a finite element software ATENA v4 [16].  The research variables were number of layers of CFRP strips (one or two layers), wrapping schemes (four sides or three sides) and orientation of CFRP strips (0/90 or 45/135 degree’s). From the analysis of the finite element results, ATENA shows it has successfully simulated the shear behaviour of strengthened and repaired of 2-span continuous RC beams externally bonded by CFRP strips. 

Behaviour of reinforced concrete beams strengthened with carbon fibre reinforced polymer laminates subjected to corrosion damage

2000 ◽  
Vol 27 (5) ◽  
pp. 1005-1010 ◽  
Author(s):  
Khaled A Soudki ◽  
Ted G Sherwood
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fibre ◽  
Concrete Beams ◽  
Corrosion Damage ◽  
Corrosion Process ◽  
Reinforced Concrete Beams ◽  
Cfrp Laminates ◽  
Reinforced Polymer ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer

The viability of carbon fibre reinforced polymer (CFRP) laminates for the strengthening of corrosion damaged reinforced concrete bridge girders is addressed in this paper. Ten reinforced concrete beams (100 × 150 × 1200 mm) with variable chloride levels (0-3%) were constructed. Six beams were strengthened by externally epoxy bonding CFRP laminates to the concrete surface. The tensile reinforcements of three unstrengthened and four strengthened specimens were subjected to accelerated corrosion by means of impressed current to 5, 10, and 15% mass loss. Strain gauges were placed on the CFRP laminates to monitor and quantify tensile strains induced by the corrosion process. Following the corrosion phase, the specimens were tested in flexure in a four-point bending regime. Test results revealed that CFRP laminates successfully confined the corrosion cracking, and the total expansion of the laminate exhibited an exponential increase throughout the corrosion process. All the strengthened beams exhibited increased stiffness over the unstrengthened specimens and marked increases in the yield and ultimate strength. The CFRP strengthening scheme was able to restore the capacity of corrosion damaged concrete beams up to 15% mass loss.Key words: CFRP laminates, corrosion, confinement, expansion, load tests, strengthening, bond strength, reinforced concrete.

Impact resonance method for fatigue damage detection in reinforced concrete beams with carbon fibre reinforced polymer

2005 ◽  
Vol 32 (6) ◽  
pp. 1093-1102 ◽  
Author(s):  
Catalin Gheorghiu ◽  
Jamal Eddine Rhazi ◽  
Pierre Labossière
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fibre ◽  
Fatigue Damage ◽  
Concrete Beams ◽  
Resonance Method ◽  
Rc Beams ◽  
Reinforced Polymer ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Impact Resonance

This paper reports on the potential of using the impact resonance method (IRM) for detecting fatigue damage in strengthened reinforced concrete (RC) beams. In this experimental program, 1.2 m long RC beams strengthened with a carbon fibre reinforced polymer (CFRP) plate have been employed. The specimens were subjected to fatigue loading under four-point bending for up to 2 × 106 cycles at 3 Hz. The load amplitude was varying from 15% to 75% of the cycles yielding load of the beam. Throughout fatigue testing, the cycling was stopped for IRM measurements to be taken. The obtained data provided information about changes in modal properties, such as, fundamental frequencies and damping ratios. Moreover, the results have shown that the IRM technique was successfully employed in laboratory for detecting fatigue damage in concrete beams strengthened with CFRP laminates.Key words: impact resonance method, modal properties, RC beam, FRP-strengthening, fatigue test, cracking.

Shear behavior of reinforced concrete beams strengthened in flexure with bonded carbon fibre reinforced polymers laminates

2005 ◽  
Vol 32 (5) ◽  
pp. 812-824 ◽  
Author(s):  
Francesco Bencardino ◽  
Vincenzo Colotti ◽  
Giuseppe Spadea ◽  
Ramnath Narayan Swamy
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fibre ◽  
Shear Behavior ◽  
Structural Performance ◽  
Rc Beams ◽  
Shear Reinforcement ◽  
Brittle Behavior ◽  
Reinforced Polymer ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer

The aim of this paper is to clarify the structural performance of reinforced concrete (RC) beams with weak or without any internal shear reinforcement and externally strengthened in flexure with carbon fibre reinforced polymer (CFRP) laminates, when subjected to a shear-dominant-loading regime. Seven RC beams were specifically designed, without and with an external anchorage system, which was carefully detailed to enhance the benefits of the strengthening laminate and counteract the destructive effects of shear forces. All the beams were identical in terms of their geometry, longitudinal internal reinforcement, and concrete strength but varied, to highlight the role of shear behavior, in terms of their internal and external shear reinforcement as well as in their loading test regime. The beams were tested under four-point bending and extensively instrumented to monitor strains, deflection, cracking, load carrying capacity, and failure modes. The structural response of the tested beams has, then, been critically analyzed in terms of deformability, strength, and failure processes that occur under a shear-dominant loading regime. It is shown that with a carefully designed anchorage system, a brittle behavior without yielding of tension steel reinforcement of a flexural strengthened beam can be transformed to a less brittle behavior with yielding of tension steel reinforcement and a well-defined enhancement of structural performance in terms of both deformation and strength. The results presented in this paper should enable engineers to counteract shear failure of externally strengthened beams with little or even no internal shear reinforcement.Key words: carbon fibre reinforced polymer, shear behavior, external flexural strengthening, structural performance.

scholarly journals Behaviour of Reinforced Concrete Beams Bonded with Glass Fibre Reinforced Polymer and Carbon Fibre Reinforced Polymer Sheets

2020 ◽  
Vol 9 (3) ◽  
pp. 134-138
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fibre ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced ◽  
Cfrp Sheets ◽  
Reinforced Polymer ◽  
Externally Bonded ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer

Concrete, a mixture of different aggregates bonded with cement, first developed around 150BC in Rome has been bedrock to the modern Infrastructure. It is used to build everything from roads, bridges, dams to sky scrapers. Strengthening concrete is traditionally done by using steels but the developments in technology in recent decades allowed to use fiber reinforced plastics which are externally bonded to concrete . Such composite materials offer high strength, low weight, corrosion resistance, high fatigue resistance, easy and rapid installation and minimal change in structural geometry. This study investigates the behavior of reinforced concrete beams bonded with fiber composites. A numerical study is conducted to study the behavior of RC beam under Static third point loading. Concrete beam specimens with dimensions of 150 mm width, 300 mm height, and 2600 mm length are modelled. These beams are externally bonded with Glass Fiber Reinforced Polymer (GFRP) sheets and Carbon Fibre Reinforced Polymer (CFRP) sheets. In present study, we examine the performance of reinforced concrete beams which are bonded with GFRP and CFRP sheets with various thicknesses (1, 2 & 3 mm) using ABAQUS in terms of failure modes, enhancement of load capacity, load-deflection analysis and flexural behaviour

Strengthening of Reinforced Concrete Beams Using Bamboo Fiber/Epoxy Composite Plates in Flexure

2019 ◽  
Vol 821 ◽  
pp. 465-471 ◽  
Author(s):  
Siew Choo Chin ◽  
Jacky Neing Sheng Moh ◽  
Shu Ing Doh ◽  
Fadzil Mat Yahaya ◽  
Jolius Gimbun
Keyword(s):  
Tensile Strength ◽  
Reinforced Concrete ◽  
Composite Plate ◽  
Natural Fiber ◽  
Fiber Composite ◽  
Composite Plates ◽  
Bamboo Fiber ◽  
Reinforced Concrete Beams ◽  
Bending Test ◽  
Rc Beams

Fiber reinforced polymer (FRP) is widely used in the construction industry for structural strengthening due to their outstanding mechanical properties. However, the production of synthetic fibers such as FRP is detrimental to the environment. Alternatively, natural fiber composite may be used as external strengthening material. This paper presents the potential of bamboo fiber composite plate (BFCP) to strengthen the reinforced concrete (RC) beams in flexure. The bamboo of species Dendrocalamus asper was used to produce the fiber and fiber-to-volume ratio was set at 2:5. The composite plate was fabricated by binding bamboo fibers with epoxy using a hand-lay-up method. The flexural and tensile strength of the BFCP was measured and all the beams were tested to failure under four-point bending test. It was found that BFCP exhibited a higher flexural and tensile strength compared to pure epoxy samples. Meanwhile, the RC beams strengthened using BFCP exhibited an increment of 10-12% in beam structural capacity compared to the un-strengthened beams. Bonding of BFCP in the flexure zone was able to divert the vertical cracks into diagonal at the edge of the composite plate. Findings from this work may serve as a useful guide to strengthen RC beams using a BFCP.

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