Effectiveness of prestressed Carbon Fibre Reinforced Polymer (CFRP) sheets for rehabilitation of prestressed concrete girders

Carbon fibre reinforced polymer (CFRP) is currently used to reinforce buildings in civil engineering in the common forms of sheets, while the utilization efficiency of a CFRP materials greatly decreased when the CFRP material is directly bonded to the structure because of the lack of the effect of the exertion of a prestress. A paper spool-inspired anchoring method is proposed to overcome the shearing problem in the anchoring system through the friction between layers. Anchoring and jack-up tensioning devices for CFRP sheets are also designed and produced. A prestress is successfully applied to single and multiple CFRP sheets (80% tensioning strength is achieved), thus verifying the tensioning effect of the prestress. Based on these results, prestressed concrete flat slabs were designed with pretensioned CFRP sheets. The corresponding mechanical properties of the concrete flat slabs are tested to verify the feasibility of using CFRP sheets to apply a prestress. The results show that the uniformity of the fibre stress during the tensioning of the CFRP sheet is the key to the success of the application of the prestress.

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Flexural behaviour of concrete beams strengthened with prestressed carbon fibre reinforced polymer sheets subjected to sustained loading and low temperature

Canadian Journal of Civil Engineering ◽

10.1139/l03-091 ◽

2004 ◽

Vol 31 (2) ◽

pp. 239-252 ◽

Cited By ~ 13

Author(s):

Raafat El-Hacha ◽

Mark F Green ◽

R Gordon Wight

Keyword(s):

Low Temperature ◽

Carbon Fibre ◽

Flexural Behaviour ◽

Prestress Losses ◽

Cfrp Sheets ◽

Reinforced Polymer ◽

Carbon Fibre Reinforced Polymer ◽

Fibre Reinforced Polymer ◽

Prestressed Cfrp Sheets

This paper presents results of an experimental investigation that examined concrete beams post-tensioned with bonded carbon fibre reinforced polymer (CFRP) sheets and then exposed to either room (+22 °C) or low (-28 °C) temperatures. The primary objective of this investigation was to assess the flexural behaviour of the strengthened beams after sustained loadings at both room and low temperatures. The strengthened beams showed significant increases in flexural stiffness and ultimate capacity as compared with the control-unstrengthened beams. Failure of the strengthened beams was by tensile rupture of the prestressed CFRP sheets. Test results showed that the long-term and low temperature effects did not adversely affect the strength of the beams. Long-term loading and low temperature exposure caused prestress losses in the CFRP sheets. The loaddeflection behaviour of the long-term beams was predicted accurately by an analytical model. These results suggest that bonded prestressed CFRP sheets could be used to increase the strength of damaged prestressed concrete girders under extreme environmental conditions.Key words: strengthening, anchorage, low temperature, long-term, prestress losses, sustained load, carbon fibre reinforced polymer sheet.

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Strengthening precast-prestressed hollow core slabs to resist negative moments using carbon fibre reinforced polymer strips: an experimental investigation and a critical review of Canadian Standards Association S806-02

Canadian Journal of Civil Engineering ◽

10.1139/l06-040 ◽

2006 ◽

Vol 33 (8) ◽

pp. 955-967 ◽

Cited By ~ 10

Author(s):

Abdelhadi Hosny ◽

Ezzeldin Yazeed Sayed-Ahmed ◽

Amr Ali Abdelrahman ◽

Naser Ahmed Alhlaby

Keyword(s):

Carbon Fibre ◽

Prestressed Concrete ◽

Bending Moments ◽

Hollow Core ◽

Reinforced Polymer ◽

Carbon Fibre Reinforced Polymer ◽

Negative Moment ◽

Fibre Reinforced Polymer ◽

Prestressing Strands ◽

Negative Moments

Behaviour of precast-prestressed hollow core slabs has been extensively studied when these slabs are subjected to positive bending moments, a practical application typical of hollow core slabs. However, in many projects it may be required to have an overhanging part of the roof to act as a cantilever. In doing so, and using precast-prestressed hollow core slabs, the slabs would be subjected to negative moments, atypical for hollow core slabs. In this paper, the behaviour of precast-prestressed hollow core slabs is experimentally investigated when they are subjected to negative bending moments. A proposed strengthening detail to increase the negative moment resistance of hollow core slabs using bonded carbon fibre reinforced polymer (CFRP) strips is presented. The CFRP strips were bonded to the top side of full-scale precast-prestressed hollow core slabs in the negative moment zone in different configurations. In two of the tested slabs the bond between the prestressing strands and the concrete was initially broken (during casting of the slabs) in the negative moment zone. The slabs with the bonded CFRP strips were tested to failure and the load–deflection behaviour was recorded. The results of the tests are presented and the strength enhancement of the hollow core slabs using the proposed technique is reported. The increase in the negative moment resistance of the CFRP-bonded hollow core slabs experimentally determined is also compared with the CSA-S806-02 prediction for the moment resistance of concrete elements with bonded CFRP strips.Key words: carbon fibre reinforced polymer (CFRP) strips, hollow core slab, flexure strengthening, prestressed concrete, precast slabs, prestressing strands.

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

International Journal of Engineering and Advanced Technology - Regular Issue ◽

10.35940/ijeat.c4845.029320 ◽

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

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Flexural behaviour of reinforced or prestressed concrete beams including strengthening with prestressed carbon fibre reinforced polymer sheets: application of a fracture mechanics approach

Canadian Journal of Civil Engineering ◽

10.1139/l06-161 ◽

2007 ◽

Vol 34 (5) ◽

pp. 664-677 ◽

Cited By ~ 11

Author(s):

Yail J Kim ◽

Mark F Green ◽

R Gordon Wight

Keyword(s):

Fracture Mechanics ◽

Size Effect ◽

Carbon Fibre ◽

Prestressed Concrete ◽

Concrete Beam ◽

Concrete Beams ◽

Mechanics Model ◽

Reinforced Polymer ◽

Carbon Fibre Reinforced Polymer ◽

Fibre Reinforced Polymer

This paper describes the application of a fracture mechanics model (Hillerborg 1990) to concrete structures, including strengthening with prestressed carbon fibre reinforced polymer (CFRP) sheets. One benefit of the proposed fracture mechanics model, consisting of a unique combined stress–strain response of concrete, is that it includes the size effect of reinforced concrete beams; however, its application and validation have not been fully investigated. The proposed model is reviewed and further developed to cover prestressed concrete beams including a beam strengthened with a prestressed CFRP sheet. To evaluate the model, various approaches such as finite element analysis, a strength-based model, a conventional design method, and experimental results are compared with the fracture mechanics model. The size-dependent parameter (ε1) significantly affects the predicted behaviour of reinforced or prestressed concrete beams, depending on the contribution of reinforcement. Based on the current assessment, ε1 = 0.005 is recommended as an upper limit for normal strength concrete.Key words: carbon fibre reinforced polymer sheet, flexure, fracture mechanics, prestressed concrete beam, reinforced concrete beam, strengthening, size effect.

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Accelerated corrosion and repair of reinforced concrete columns using carbon fibre reinforced polymer sheets

Canadian Journal of Civil Engineering ◽

10.1139/l00-030 ◽

2000 ◽

Vol 27 (5) ◽

pp. 941-948 ◽

Cited By ~ 49

Author(s):

C Lee ◽

J F Bonacci ◽

M DA Thomas ◽

M Maalej ◽

S Khajehpour ◽

...

Keyword(s):

Reinforced Concrete ◽

Carbon Fibre ◽

Concrete Columns ◽

Corrosion Monitoring ◽

Reinforced Concrete Columns ◽

Accelerated Corrosion ◽

Cfrp Sheets ◽

Reinforced Polymer ◽

Carbon Fibre Reinforced Polymer ◽

Fibre Reinforced Polymer

An experimental study on the simulation of corrosion in large-scale reinforced concrete columns and their repair using carbon fibre reinforced polymer (CFRP) sheets is presented. Seven columns were subjected to an accelerated corrosion regime, wrapped using CFRP sheets, then tested to structural failure and (or) subjected to further post-repair accelerated corrosion, monitoring, and testing. Accelerated corrosion was achieved by adding sodium chloride to the mixing water, applying a current to the reinforcement cage, and subjecting the specimens to cyclic wetting and drying. Results showed that the CFRP repair greatly improved the strength of the repaired member and retarded the rate of post-repair corrosion. Moreover, subjecting the repaired column to extensive, post-repair corrosion resulted in no loss of strength or stiffness and only a slight reduction in the ductility of the repaired member.Key words: accelerated corrosion, carbon fibre reinforced polymer, composites, corrosion damage, corrosion rate, external confinement, reinforced concrete columns.

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Strengthening of concrete columns with carbon fibre reinforced polymer wrap

Canadian Journal of Civil Engineering ◽

10.1139/l03-007 ◽

2003 ◽

Vol 30 (3) ◽

pp. 543-554 ◽

Cited By ~ 13

Author(s):

P L Shrive ◽

A Azarnejad ◽

G Tadros ◽

C McWhinnie ◽

N G Shrive

Keyword(s):

Carbon Fibre ◽

Prestressed Concrete ◽

Concrete Columns ◽

Element Model ◽

Maximum Load ◽

Design Methods ◽

Reinforced Polymer ◽

Confining Effect ◽

Carbon Fibre Reinforced Polymer ◽

Fibre Reinforced Polymer

Reinforced and prestressed concrete columns with one or two layers of carbon fibre reinforced polymer (CFRP) wrap were tested to failure in axial compression. When the results were compared with the maximum load predictions of two proposed design methods, the predictions consistently underestimated actual loads. The design methods are thus conservative. A simple analysis for circular columns reveals that the confining effect of the wrap is not engaged until the concrete actually starts failing and dilating. A finite element model of a chamfered square column confirms this analysis, as do strain readings from the tests. It is shown that strength gains are not linearly related to wrap thickness. The failure mechanism suggests that design should not be based on the ultimate strength or strain of the wrap and that strength gains can be expected to reduce with increasing brittleness of the concrete and with increasing eccentricity.Key words: concrete columns, FRP wrap, reinforced, strengthening.

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