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CFRP

FRPEpoxy

FRP

FRP

AB

FRPCFRP

Abaqus

FECFRP

CFRPAbaqus

[email protected]

FRP

FRP

FRP

FRP

FRPFRP

FRP

FRP :

FRP

FRP

FRP /

FRP

FRP

FRPFRP

FRP

EBROG

FRP

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FRP

1 Debonding

CFRP

FRP

AB

Leong Kok

Ec

(MPa)

FRP

A

Leong Kok

f'c

(MPa)

f't

(MPa)

B

FRP

a S

(MPa)

CFRP

AB

(mm)

S L d

Abaqus

FRP

FRP

FRP

CFRP

h

b

A1

A2

A3

B1

B2

B3

Abaqus

FRP

FRP

Leong Kok

A

B

Leong Kok

FRP

(MPa)Ep (GPa)

ta (mm)

Ga (MPa)

Ea (MPa)

E fu y fy

(GPa)

(MPa)

(%)

(MPa)

(mm)

R6 A

T10

R12

B

T20

CFRP

FRP

FEM

FRP

CDP

CDP

0.1

1.1

1.16

1.16

1 Concrete Damaged Plasticity 2 Bond-Slip 3 Dowel Action 4 Dilation Angle 5 Eccentricity

Dilation angle

0

50000

100000

150000

200000

250000

300000

Forc

e (N

)

.

Eccentricity

Dilation angle

0 0.01

k

CDP

fb0/fc0

Eccentricity

1 Cracking strain

01 0.02 Displacement (m)

Viscosity Parameterk

Cracking strain

0.03Displacement (m)

1.0

Viscosity Parameter

td

.

Cracking strain

0.04 0.Displacement (m)

k

0.5

Viscosity Parameter

Abaquscr

.05 0.06

A1

A2

A3

B1

B2

B3

cr

Abaqus

1

2

3

1

2

3

fy

CFRP

FRP

Es

u

FRP

MPa

cr

FRP

(MPa)

(MPa)

CFRP

* Traction

.Obaidat

FRP

Traction-Separation

FRP

CFRP

Separation

Lamina

Lamina

EG1

G2

nst

ctf

FRP

Abaqus

BK

w/c=0.5

* Benzaggah-Kenane

sweep

FRP

* Embedded

Tie

sweep

B1

B2B3

A1B1

A1B1

A2A3

FRP

structure

FRP

e

ShellS4R

COH3D8

Quad

e

e

CFRPShell

COH3D8

Cohesive

CFRP

FRP

C3D8R

CFRP

Cohesive

Hex

C3D8R

T3D2

Hex

CFRP

A1B1

CFRP

FRP

AB

FEM (N)

N

FRP

mm

-

FRP A1

FRP

A2

FRP

A3

-

FRP B1

FRP

B2

FRP

B3

AB

A1B1

A2A3B2B3

AB

A2

CFRPCFRP

FRP

Abaqus

CFRP

FRP

B

CFRP

CFRP

CFRP

CFRP

A

(m)

CFRP

CFRP

CFRP

FE

(m)

Abaqus

CFRP

FEA

CFRP

FEM

Abaqus

CFRP

FEA

CFRP

CFRP

CFRP

CFRP

CFRP

CFRP

CFRP

CFRP

CFRP

FEA

CFRP

CFRP

[8] Morita, S., Kaku, T. Local bond stress

relationship under repeated loading Symposium on resistance and ultimate deformability of structures acted on by welldefined repeated load, Preliminary report, international association of bridge structure engineering, Lisbon symposium, 2211993.

FRP

[11]

Lu XZ, Ten JG, Ye LP, Jaing JJ

models for FRP sheets/plates bonded to concrete

Eng Struct, 24(5), 920

(N/m2)

(N/m2)

AB

CFRP

, S., Kaku, T. Local bond stress

relationship under repeated loading Symposium on resistance and ultimate deformability of structures acted on by welldefined repeated load, Preliminary report, international association of bridge structure

ng, Lisbon symposium, 221

FRP

Lu XZ, Ten JG, Ye LP, Jaing JJ

models for FRP sheets/plates bonded to Eng Struct, 24(5), 920

CFRP

CFRP

, S., Kaku, T. Local bond stress

relationship under repeated loading Symposium on resistance and ultimate deformability of structures acted on by welldefined repeated load, Preliminary report, international association of bridge structure

ng, Lisbon symposium, 221

FRP

Lu XZ, Ten JG, Ye LP, Jaing JJ Bond

models for FRP sheets/plates bonded to Eng Struct, 24(5), 920 37, 2005.

CFRP

[1]

[2]

[3]

[4]

[5]

[6]

[7]

, S., Kaku, T. Local bond stress-slip

relationship under repeated loading Symposium on resistance and ultimate deformability of structures acted on by well-defined repeated load, Preliminary report, international association of bridge structure

ng, Lisbon symposium, 221-227,

Bond-slip

models for FRP sheets/plates bonded to 37, 2005.

(m)

(m)

[1]

Mukhopadhyaya

shear stress: a new design criterion for plate debonding , Journal of Composites Construct, ASCE, 5, 35

[2]

Kok, L. Effect of beam size & FRP thickness

on interfacial shear stress concentrationfailure mode in FRP strengthened beam MS thesis, Singapor, 2004.

[3]

Hansen, E., Willam, K., Carol, I. A two

surface anisotropic damage/plasticity model for plain concrete Proc. FramcosFracture Mechanics of Concrete Materials, 549556, Rotterdam, 2001.

[4]

Abaqus Theory manual and user man

Example Manual Version 6.10. Providence, 2010.

[5]

Taqieddin, ZN. Elasto

Modeling of Reinforced Concrete Ph.D. dissertation, Dept. Civil & Environmental Engineering, Louisiana State Univ. Baton Rouge LA, 2008.

[6] Abaqus V6.1

Systemes. 2010[7]

Obaidat, Y.T., Heyden, S., Dahlblom, O. The

effect of CFRP and CFRP/concrete interface models when modeling retrofitted RC beams with FEM Journal of Composite Structures, 92, 1391 1398, 2010.

Mukhopadhyaya, P. Swamy

stress: a new design criterion for plate , Journal of Composites Construct,

43, 2001. Kok, L. Effect of beam size & FRP thickness

on interfacial shear stress concentrationfailure mode in FRP strengthened beam MS

apor, 2004.


surface anisotropic damage/plasticity model for concrete Proc. Framcos

Fracture Mechanics of Concrete Materials, 549556, Rotterdam, 2001.

Abaqus Theory manual and user man

Example Manual Version 6.10. Providence,

Taqieddin, ZN. Elasto-

Modeling of Reinforced Concrete Ph.D. dissertation, Dept. Civil & Environmental Engineering, Louisiana State Univ. Baton Rouge LA, 2008.

Abaqus V6.10 Manuals Providence, Dassault

Systemes. 2010


effect of CFRP and CFRP/concrete interface models when modeling retrofitted RC beams with FEM Journal of Composite Structures,

1398, 2010.

P. Swamy, RN. Interface





surface anisotropic damage/plasticity model for concrete Proc. Framcos-4 Conf. Paris

Fracture Mechanics of Concrete Materials, 549

Abaqus Theory manual and user manual and


-Plastic and Damage

Modeling of Reinforced Concrete Ph.D. dissertation, Dept. Civil & Environmental Engineering, Louisiana State Univ. Baton

0 Manuals Providence, Dassault



(m)

Interface




Hansen, E., Willam, K., Carol, I. A two-

surface anisotropic damage/plasticity model for 4 Conf. Paris

Fracture Mechanics of Concrete Materials, 549-

ual and


Plastic and Damage

Modeling of Reinforced Concrete Ph.D. dissertation, Dept. Civil & Environmental Engineering, Louisiana State Univ. Baton

0 Manuals Providence, Dassault



Abstract

The Modeling of Epoxy Layer for Prediction of Debonding at FRP-

Strengthened Rc Beams

H. Varastehpor Assistant professor of Civil Engineering, Institute for Energy & Hydro Technology

A. Soleimanikia

Civil structural engineer, Institute for Energy & Hydro Technology

( Received: 2014/6/9 - Accepted: 2015/4/29)

Abstract Bonding of fiber reinforced polymers (FRP) with epoxy layer has considered as a new structural strengthening technology in response to need for repair and strengthening of reinforced concrete structures and propagated in the last decade. Although epoxy bonding of FRP has many advantages, there is a common problem; before receiving the expected flexural capacity, most of the failure modes of these beams occur in a brittle manner, without any serious indication. The most commonly reported failure modes include ripping of the concrete cover and interfacial debonding. In the most researches who have studied the behavior of retrofitted structures, the effect of the interfacial behavior has been ignored. Proper prediction of flexural capacity of FRP strengthened of concrete beams in debonding modes is led to economical benefits in projects. In this article, the results have been verified with 6 beams in laboratory that have been loaded in two symmetric points load and divided to groups A and B. The beams had the same section, length and number of CFRP layer in each group, but thickness of CFRP was different. A nonlinear modeling with Finite Element (FE) method with the help of Abaqus is done, for investigation of real behavior of CFRP strengthened concrete beams and interfacial shear stresses concentration at CFRP cut off region, with presenting the failure theory and criterion and a method for cohesive layer simulation. Moreover the FE results are verified with an accurate experimental test results. The FEM results agreed well with the experiments, when using the cohesive model regarding failure modes, load capacity, force-displacement curves results and CFRP strains.

Keywords: Flexural capacity, Debonding, FRP, Epoxy leyer, Abaqus

Corresponding author: [email protected]

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