CFRP

FRPFiber Reinforced Polymer

FRP

CFRPCarbon-FRP

CFRP

CFRP.

n.moshiri@cv.iut.ac.ir

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FRP

FRP

FRP

FRP

FRP

FRP

1

Fiber Reinforced Polymer

FRP

CFRPFRP

FRP

FRP

FRP

2

Carbon FRP

FRP

FRP

wet layup

FRPEBR

FRP

EBROG

1

Externally Bonded Reinforcement 2 Externally Bonded Reinforcement On Grooves

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x

FRP

FRP

FRP

EBRIG EBROG

EBROG

1 Externally Bonded Reinforcement In Grooves

FRP

NSM NSM

FRP

wet lay-upFRP

×

(Matrix-Filled Groove) MFG

3-EBROG-T

EBROG

FRP

T

2

Near Surface Mounted

ThickFRP

3-EBROG-SE

EBROG

SE

Sand and Epoxy

3-EBROG-T-SE

FRP

EBROG

FRP

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EBRNSM

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EBROGEBRIG

FRP

FRP

EBRIG

FRP

NSM

wet lay-up

NSM

FRP

FRPNSM

2-MFG

2-MFG(2)

FRP

-EBROG-T

EBROG

1-EBROG

FRP

3-EBROG-TEBROG

3-EBROG-SE

EBROG

3-EBROG-T-SE

NSM

FRP

EBRIG EBROG

3

EBROG

3-EBROG-T

EBR

T

LVDT

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EBROG

1-EBROG

FRP

3-EBROG-TEBROG

3-EBROG-SE

EBROG

3-EBROG-T-SEFRP

FRPkN%

1-Control

1-EBR

1-EBROG

1-EBRIG

1-NSM

2-Control

2 MFG

2-MFG(2)

3-Control

3-EBROG-T

3 EBROG-SE

3 EBROG-T-SE

ر مشيرينيلوف، نژاد داوود مستوفي

15/ لوا تحقيقات بتن، سال ششم، شمارة

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هاي مختلفهاي گروهكرنش نمونه-نيرو نمودار -3شكل

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[1]. Wang Z, Wang D, Smith S, Lu D. "CFRPConfined Square RC Columns. II: Cyclic Axial Compression StressComposites for Construction. Vol. 16, No. 2, pp. 161-170, 2012.[2]. Csuka B, Koll?r LP. "Analysis of FRP confined columns under eccentric loading". Composite Structures. Vol. 94, No. 3, pp. 11061116, 2012.[3]. Piekarczyk J, Piekarczyk W, Blazewicz S. "Compression strength of concrete cylinders reinforced Construction and Building Materials. Vol. 25, No. 5, pp. 2365-[4]. Tan K. "Strength enhancement of rectangular reinforced concrete columns using fiberpolymer". Journal of Composites for Construction. Vol. 6, No. 3, pp. 175[5]. ACI Committee 440. Guide for the design and construction of externally bonded FRP systems for strengthening concrete structures. ACI 440.2RFarmington Hills, MI, USA 2008.[6]. Technical Report No. 55. Design guidanstrengthening concrete structures using fiber composite materials. UK: The Concrete Society; 2004. [7]. JSCE. Recommendations for upgrading of concrete structures with use of continuous fiber sheets. Concrete Engineering Series; Vol. 41; 2001. [8]. Au C, Buyukozturk O. "Effect of fiber orientation and ply mix on fiber reinforced polymer-confined concrete". Journal of Composites for Construction. Vol. 9, No. 5, pp. 397-407, 2005.[9]. Issa M, Alrousan R, Issa M. "Experimental and parametric study of cconfined with CFRP composites". Journal of Composites for Construction. Vol. 13, No. 2, pp. 135-147, 2009.[10]. Li G, Maricherla D, Singh K, Pang SM. "Effect of fiber orientation on the structural behavior of FRP wrapped con

[1]. Wang Z, Wang D, Smith S, Lu D. "CFRPConfined Square RC Columns. II: Cyclic Axial Compression Stress-Strain Model". Journal of Composites for Construction. Vol. 16, No. 2, pp.

170, 2012.

[2]. Csuka B, Koll?r LP. "Analysis of FRP confined columns under eccentric loading". Composite Structures. Vol. 94, No. 3, pp. 11061116, 2012.

[3]. Piekarczyk J, Piekarczyk W, Blazewicz S. "Compression strength of concrete cylinders reinforced with carbon fiber laminate". Construction and Building Materials. Vol. 25, No.

-2369, 2011.

[4]. Tan K. "Strength enhancement of rectangular reinforced concrete columns using fiberpolymer". Journal of Composites for Construction.

. 6, No. 3, pp. 175-183, 2002.[5]. ACI Committee 440. Guide for the design and construction of externally bonded FRP systems for strengthening concrete structures. ACI 440.2RFarmington Hills, MI, USA 2008.[6]. Technical Report No. 55. Design guidanstrengthening concrete structures using fiber composite materials. UK: The Concrete Society;

[7]. JSCE. Recommendations for upgrading of concrete structures with use of continuous fiber sheets. Concrete Engineering Series; Vol. 41;

Au C, Buyukozturk O. "Effect of fiber orientation and ply mix on fiber reinforced

confined concrete". Journal of Composites for Construction. Vol. 9, No. 5, pp.

407, 2005.

[9]. Issa M, Alrousan R, Issa M. "Experimental and parametric study of cconfined with CFRP composites". Journal of Composites for Construction. Vol. 13, No. 2, pp.

147, 2009.

[10]. Li G, Maricherla D, Singh K, Pang SM. "Effect of fiber orientation on the structural behavior of FRP wrapped con

FRP

[1]. Wang Z, Wang D, Smith S, Lu D. "CFRPConfined Square RC Columns. II: Cyclic Axial

Strain Model". Journal of Composites for Construction. Vol. 16, No. 2, pp.

[2]. Csuka B, Koll?r LP. "Analysis of FRP confined columns under eccentric loading". Composite Structures. Vol. 94, No. 3, pp. 1106

[3]. Piekarczyk J, Piekarczyk W, Blazewicz S. "Compression strength of concrete cylinders

with carbon fiber laminate". Construction and Building Materials. Vol. 25, No.

[4]. Tan K. "Strength enhancement of rectangular reinforced concrete columns using fiberpolymer". Journal of Composites for Construction.

183, 2002.

[5]. ACI Committee 440. Guide for the design and construction of externally bonded FRP systems for strengthening concrete structures. ACI 440.2RFarmington Hills, MI, USA 2008.

[6]. Technical Report No. 55. Design guidanstrengthening concrete structures using fiber composite materials. UK: The Concrete Society;

[7]. JSCE. Recommendations for upgrading of concrete structures with use of continuous fiber sheets. Concrete Engineering Series; Vol. 41;

Au C, Buyukozturk O. "Effect of fiber orientation and ply mix on fiber reinforced

confined concrete". Journal of Composites for Construction. Vol. 9, No. 5, pp.

[9]. Issa M, Alrousan R, Issa M. "Experimental and parametric study of circular short columns confined with CFRP composites". Journal of Composites for Construction. Vol. 13, No. 2, pp.

[10]. Li G, Maricherla D, Singh K, Pang SM. "Effect of fiber orientation on the structural behavior of FRP wrapped concrete cylinders".

FRP

[1]. Wang Z, Wang D, Smith S, Lu D. "CFRP-Confined Square RC Columns. II: Cyclic Axial

Strain Model". Journal of Composites for Construction. Vol. 16, No. 2, pp.

[2]. Csuka B, Koll?r LP. "Analysis of FRP confined columns under eccentric loading". Composite Structures. Vol. 94, No. 3, pp. 1106-

[3]. Piekarczyk J, Piekarczyk W, Blazewicz S. "Compression strength of concrete cylinders

with carbon fiber laminate". Construction and Building Materials. Vol. 25, No.

[4]. Tan K. "Strength enhancement of rectangular reinforced concrete columns using fiber-reinforced polymer". Journal of Composites for Construction.

[5]. ACI Committee 440. Guide for the design and construction of externally bonded FRP systems for strengthening concrete structures. ACI 440.2R-08.

[6]. Technical Report No. 55. Design guidance for strengthening concrete structures using fiber composite materials. UK: The Concrete Society;

[7]. JSCE. Recommendations for upgrading of concrete structures with use of continuous fiber sheets. Concrete Engineering Series; Vol. 41;

Au C, Buyukozturk O. "Effect of fiber orientation and ply mix on fiber reinforced

confined concrete". Journal of Composites for Construction. Vol. 9, No. 5, pp.

[9]. Issa M, Alrousan R, Issa M. "Experimental ircular short columns

confined with CFRP composites". Journal of Composites for Construction. Vol. 13, No. 2, pp.

[10]. Li G, Maricherla D, Singh K, Pang S-S, John M. "Effect of fiber orientation on the structural

crete cylinders".

EBROG

EBRIG

-Confined Square RC Columns. II: Cyclic Axial

Strain Model". Journal of Composites for Construction. Vol. 16, No. 2, pp.

[2]. Csuka B, Koll?r LP. "Analysis of FRP confined columns under eccentric loading".

-

[3]. Piekarczyk J, Piekarczyk W, Blazewicz S. "Compression strength of concrete cylinders

with carbon fiber laminate". Construction and Building Materials. Vol. 25, No.

[4]. Tan K. "Strength enhancement of rectangular reinforced

polymer". Journal of Composites for Construction.

[5]. ACI Committee 440. Guide for the design and construction of externally bonded FRP systems for

08.

ce for strengthening concrete structures using fiber composite materials. UK: The Concrete Society;

[7]. JSCE. Recommendations for upgrading of concrete structures with use of continuous fiber sheets. Concrete Engineering Series; Vol. 41;

Au C, Buyukozturk O. "Effect of fiber orientation and ply mix on fiber reinforced

confined concrete". Journal of Composites for Construction. Vol. 9, No. 5, pp.

[9]. Issa M, Alrousan R, Issa M. "Experimental ircular short columns

confined with CFRP composites". Journal of Composites for Construction. Vol. 13, No. 2, pp.

S, John M. "Effect of fiber orientation on the structural

crete cylinders".

...

FRP

EBRIG

FRP

FRP

FRP

wet lay

FRP

EBR

/

FRP

FRP

wet lay-up

NSM

FRP

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Composite Structures. Vol. 74, No. 4, pp. 475-483, 2006. [11]. Mostofinejad D, Mahmoudabadi E. "Grooving as alternative method of surface preparation to postpone debonding of FRP laminates in concrete beams". Journal of Composites for Construction. Vol. 14, No. 6, pp. 804-811, 2010.

][

(EBRIG)

FRP

][

FRP.

[14]. Mostofinejad D, Shameli SM. "Externally bonded reinforcement in grooves (EBRIG) technique to postpone debonding of FRP sheets in strengthened concrete beams". Construction and Building Materials. Vol. 38, No., pp. 751-758, 2013.

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CFRP

Abstract

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Compressive Strength of RC Columns Strengthened with Longitudinal CFRP

Composites

Davood Mostofinejad Professor, Department of Civil Engineering, Isfahan University of Technology

Niloufar Moshiri

M.Sc. in Structural Engineering, Department of Civil Engineering, Isfahan University of Technology

( Received: 2014/2/23 - Accepted: 2014/7/14)

Abstract Confining RC columns by FRP composites with fibers oriented in the hoop direction is the most common method of strengthening columns. In the present study, however, the application of CFRP composites with fibers aligned along the column s axis to improve compressive strength of RC columns has been investigated. Global buckling of composite with longitudinal fibers may result in debonding of FRP from column surface, and thus, the compressive load carrying capacity of the strengthened column would not be increased considerably. To limit the global buckling of composite under compression, a newly introduced strengthening method, named as Grooving Method (GM), was utilized in the present study and its effect on postponing the buckling of CFRP fibers when aligned along the column axis was investigated. For this purpose, 12 circular RC columns with diameter of 150 mm and height of 500 mm were tested under axial compression. Experimental results showed that while the effect of installing CFRP with conventional EBR method was negligible on the columns load capacity, the grooving method considerably enhanced the columns maximum loads.

Keywords: RC column, CFRP, Buckling, Grooving Method, Compressive Strengthening.

Corresponding author: n.moshiri@cv.iut.ac.ir