Stress–strain model for circular concrete columns confined by FRP and conventional lateral steel

Fibre Reinforced Polymer (FRP) bars has attracted a significant amount of research attention in the last three decades to overcome the problems associated with the corrosion of steel reinforcing bars in reinforced concrete members. A limited number of studies, however, have investigated the behaviour of concrete columns reinforced with FRP bars. Also, available design standards either ignore the contribution of or do not recommend the use of GFRP bars in compression members. This study reports the results of experimental investigations of concrete specimens reinforced with GFRP bars and GFRP helices as longitudinal and transverse reinforcement, respectively. A total of five circular concrete columns of 205 mm in diameter and 800 mm in height were cast and tested under axial compression. The experimental results showed that reducing the spacing of the GFRP helices or confining the specimens with CFRP sheet led to improvements in the strength and ductility of the specimens. Also, an analytical model has been developed for the axial loadaxial deformation behaviour of the circular concrete columns reinforced with GFRP bars and helices. The model has been validated with the experimental results.

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“…The confined concrete strength can be determined using Eq. (15) as recommended by different authors [47][48][49].…”

Section: Confined Concretementioning

confidence: 99%

Axial load-axial deformation behaviour of circular concrete columns reinforced with GFRP bars and helices

Karim

Sheikh

Hadi

2016

Construction and Building Materials

120

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“…Andere Bemessungsansätze zur Bestimmung der Querschnittstragfähigkeit CFK‐umschnürter bewehrter Druckglieder werden z. B. in vorgestellt.…”

Section: Stand Der Technikunclassified

Zum Tragverhalten CFK‐umschnürter Stahlbetonstützen mit Kreisquerschnitt

Kaeseberg

Holschemacher

Curbach

2018

Beton und Stahlbetonbau

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Neben CFK‐(carbonfaserverstärkten Kunststoff)Lamellen, die als zusätzlich aufgeklebte oder eingeschlitzte Zugbewehrung bereits seit den 1990er Jahren erfolgreich zur Ertüchtigung bestehender Stahlbetonbauteile Einsatz finden, werden in der Baupraxis in zunehmendem Maß auch CFK‐Gelege verwendet. Mit derartigen Gelegen kann neben der Biege‐ und Querkrafttragfähigkeit von Stahlbetonplatten und ‐balken auch die Tragfähigkeit von Stahlbetonstützen nachträglich erhöht werden. Die CFK‐Gelege werden dabei mittels Epoxidharzkleber vollflächig über die gesamte Höhe der zu ertüchtigenden Stahlbetonstütze entlang ihres Umfangs angeordnet. Der auf der Oberfläche entstehende CFK‐Werkstoff behindert durch die hohe Steifigkeit der Carbonfasern die Dehnung und Ausbreitung des Betons in Querrichtung, wodurch dieser in einen dreidimensionalen Spannungszustand versetzt wird. Dies resultiert in höheren Druckfestigkeiten des umschnürten Betons und führt zu einer Veränderung des Verformungsverhaltens. Der Beitrag gibt zunächst einen Überblick zum Stand der Technik hinsichtlich Planung und Bemessung von CFK‐Umschnürungen gemäß der DAfStb‐Richtlinie „Verstärken von Betonbauteilen mit geklebter Bewehrung“ [1]. Daran anschließend werden Forschungsergebnisse aus der internationalen Literatur mit den Ergebnissen eines an der HTWK Leipzig durchgeführten Versuchsprogramms verglichen und ein Bemessungsvorschlag für CFK‐umschnürte Stützen mit Kreisquerschnitt vorgestellt.

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“…It was found that the improvement in shear behavior is observed by comparing strains in the transverse re-bars, which are increasing when more amount of GFRP strip is incorporated to the column. In [15], Fatemeh et al studied the behavior of RC columns confined by FRP and conventional lateral steel reinforcement and a constitutive stress-strain model was implemented.…”

Section: Introductionmentioning

confidence: 99%

Numerical Modeling of Reinforced Concrete Strengthened Columns Under Cyclic Loading

et al. 2017

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Although many numerical investigations are available on external strengthening of reinforced concrete columns using fiber-reinforced polymer jackets, there are few numerical investigations presented on rectangular/square reinforced concrete columns subjected to cyclic lateral loading. In the present work, numerical analyses on square reinforced concrete columns strengthened using fiber-reinforced polymer and steel bars were carried out. This paper is divided into two parts. In the first part, two numerical models were presented to predict the cyclic behavior of the columns strengthened using either glass fiber-reinforced polymer or steel bars. The results of the first part showed a good accordance between the numerical modeling and the experimental laboratory tests. The second part reports a numerical investigation that evaluates the comparative behavior of reinforced concrete columns strengthened with glass fiber-reinforced polymer subjected to cyclic lateral loading, in which a parametric study related to the amount of the glass fiberreinforced polymer material wrapping with 1-3 layers was performed. The results of the parametric study revealed that although the general behaviors of the columns are slightly similar in terms of load capacity and maximal displacement, the solicitations at the glass fiber-reinforced polymer material scale and the values of the cracks corresponding to the maximum load are different. The main objectives of this numerical modeling were to provide a comparison between the numer-B Chahmi Oucif ical models and the experimental tests and to show the necessity to perform more complex numerical simulation to describe the behavior of strengthened materials in finer scale.

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Stress–strain model for circular concrete columns confined by FRP and conventional lateral steel

Cited by 38 publications

References 17 publications

Axial load-axial deformation behaviour of circular concrete columns reinforced with GFRP bars and helices

Axial load-axial deformation behaviour of circular concrete columns reinforced with GFRP bars and helices

Zum Tragverhalten CFK‐umschnürter Stahlbetonstützen mit Kreisquerschnitt

Numerical Modeling of Reinforced Concrete Strengthened Columns Under Cyclic Loading

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