Prediction of Flexural Strength of RC Beams Strengthened with Carbon Fibre Reinforced Polymer

2007 ◽  
Vol 14 (3) ◽  
pp. 169-180 ◽  
Author(s):  
Stephen Lee, ◽  
Stuart Moy,
Keyword(s):  
Flexural Strength ◽  
Carbon Fibre ◽  
Rc Beams ◽  
Reinforced Polymer ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer

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 Flexural Properties of Chopped Kenaf and Carbon Fibre Reinforced Polymer Composites Embedded with Carbon Nanotubes

2019 ◽  
Vol 8 (4) ◽  
pp. 6842-6846
Keyword(s):  
Carbon Nanotubes ◽  
Flexural Strength ◽  
Carbon Fibre ◽  
Polymer Composites ◽  
Flexural Properties ◽  
Specimen Thickness ◽  
Reinforced Polymer ◽  
Roll Mill ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer

An experimental study was performed to investigate the flexural behaviour of chopped kenaf and carbon fibre reinforced polymer composites embedded with carbon nanotubes (CNT). The fibre content in the composites was 10 wt.% with three different CNT loadings, which were 0.5wt.%, 1.0wt.%, and 1.5wt.%. The CNT were dispersed in the epoxy resin using the mechanical stirrer and three-roll mill machine and mixed with the chopped fibres before being poured into the designated mould. Three-point bending tests were conducted with a specimen thickness and width of 4 mm and 10 mm, respectively, and a standard specimen length of 20% longer than the support span. The flexural test results showed that the chopped carbon fibre reinforced polymer (CFRP) with 0.5wt.% CNT exhibited the highest flexural strength and modulus (42 MPa and 2.9 GPa, respectively) compared to other composites with 1.0wt.% and 1.5wt.% CNT loading. The chopped kenaf fibre reinforced polymer (KFRP) composite with 0.5wt.% CNT loading showed the highest increase in the flexural strength and modulus, at 30 MPa and 2.8 GPa, respectively. Hence, it was concluded that the addition of CNT improved the flexural properties and 0.5 wt.% CNT was the ideal loading to enhance the flexural properties of chopped fibre-reinforced polymer composites.

Impact resonance method for damage detection in carbon-fibre-reinforced polymer–strengthened reinforced concrete beams subjected to fatigue and thermal cycling

2008 ◽  
Vol 35 (11) ◽  
pp. 1251-1260 ◽  
Author(s):  
C. Ward ◽  
N. Rattanawangcharoen ◽  
C. Gheorghiu
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fibre ◽  
Resonance Method ◽  
Experimental Program ◽  
Rc Beams ◽  
Structural Health ◽  
Reinforced Polymer ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Impact Resonance

Much of North America’s civil infrastructure is rapidly aging and, in some cases, exceeding its design life and load. To combat this, the exploration of simple and effective methods for rehabilitation and structural health monitoring has been receiving much attention in industry and academia. This paper reports on the use of the impact resonance method (IRM) for evaluating the structural health of thermal-cycled reinforced concrete (RC) beams with and without externally strengthened carbon-fibre-reinforced polymer (CFRP) pultruded plates. In the experimental program, 1.2 m long specimens were subjected to 55 thermal cycles ranging from +23 to −18 °C. Fatigue loading consisting of up to two million cycles at high and low stress levels was performed. At pre-determined load cycle intervals, the loading was stopped and the IRM was performed on the specimens. Parameters including the appearance of the fast Fourier transform (FFT) spectrum of the specimens’ vibration, modal fundamental frequencies, and dynamic properties were used to assess damage in the specimen. Conclusions were made regarding the use of the IRM in monitoring the health of strengthened and unstrengthened RC beams subjected to thermal and fatigue cycles.

scholarly journals EXPERIMENTAL AND ANALYTICAL INVESTIGATION OF THE EFFECT OF FIBRE REINFORCED POLYMER ON THE SHEAR STRENGTH OF REINFORCED CONCRETE BEAMS

2020 ◽  
Vol 4 (3) ◽  
pp. 60-71
Author(s):  
Nurudeen Yusuf ◽  
J. M. KAURA ◽  
A. Ocholi ◽  
M. Abbas ◽  
A. Mohammed
Keyword(s):  
Shear Strength ◽  
Carbon Fibre ◽  
Experimental Results ◽  
Rc Beams ◽  
Cfrp Laminate ◽  
Cfrp Laminates ◽  
Reinforced Polymer ◽  
Analytical Results ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer

This paper presents the experimental and analytical results of the contribution of carbon fibre reinforced polymer (CFRP) laminates to the shear strength of RC beams. To assess the efficiency of the carbon fibre reinforced polymer (CFRP)  laminates on the strengthened specimens, twelve identical beams of cross-sectional dimensions 150x150x750mm were cast, out of which three are un-strengthened and nine were strengthened with U-wrap strips at 100 mm away from each support at varying CFRP laminates layers of  single, double and triple amounts. The prepared specimens were subjected to a three-point bending test. The results obtained revealed that the CFRP laminate increased the shear strength of the strengthened specimens over the control (un-strengthened) by 35.06%, 54.40% and 69.30% for single, double and triple layers of CFRP laminate respectively. The experimental results was also compared with the analytical results obtained based on the equation proposed by Khalifa et al., 1998. The analytical results obtained from the equation closely agreed with the experimental results. Therefore, it implies that the CFRP has the potentials of strengthening shear defiant RC beams.

Experimental and numerical study on the effect of repairing reinforced concrete cracked beams strengthened with carbon fibre reinforced polymer laminates

2014 ◽  
Vol 41 (3) ◽  
pp. 222-231 ◽  
Author(s):  
P. Duarte ◽  
J.R. Correia ◽  
J.G. Ferreira ◽  
F. Nunes ◽  
M.R.T. Arruda
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fibre ◽  
Fracture Energy ◽  
Numerical Study ◽  
Structural Response ◽  
Rc Beams ◽  
Cfrp Laminates ◽  
Reinforced Polymer ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer

This paper presents experimental and numerical investigations on the effect of repairing cracks in reinforced concrete (RC) beams prior to strengthening them with carbon fibre reinforced polymer (CFRP) laminates. The experimental campaign comprised flexural tests on three types of full-scale RC beams with T-shaped cross-section: (i) two reference un-strengthened beams, (ii) two CFRP-strengthened beams previously loaded and cracked, and (iii) two CFRP-strengthened beams, previously loaded, cracked and repaired with epoxy resin. The repair and strengthening techniques consisted of respectively injecting the cracks with epoxy resin and applying CFRP laminates according to the externally bonding reinforcement technique. In the numerical study, the structural response of all beams tested was simulated using the finite element software Atena, which features a smeared cracked model constitutive relationship for concrete. A parametric study was carried out in which the influence of material parameters, namely the fracture energy, on the beams structural response was assessed. Experimental results showed that repairing cracks by means of epoxy injection before strengthening them with CFRP laminates provided a considerable increase of stiffness, but only a slight increase of ultimate strength, as failure was triggered by the debonding of the strengthening system at the anchorage zones. In the numerical study a very good agreement with experimental data was obtained. For the repaired and strengthened beams, such agreement was obtained by increasing concrete’s fracture energy when compared to that of the reference beams.

Influence of Ply Stacking Sequences on the Impact Response of Carbon Fibre Reinforced Polymer Composite Laminates

2019 ◽  
Author(s):  
Kristian Gjerrestad Andersen ◽  
Gbanaibolou Jombo ◽  
Sikiru Oluwarotimi Ismail ◽  
Segun Adeyemi ◽  
Rajini N ◽  
...  
Keyword(s):  
Carbon Fibre ◽  
Polymer Composite ◽  
Composite Laminates ◽  
Impact Response ◽  
Reinforced Polymer ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
The Impact
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