BASALT FRP for STRENGTHENING of RC BEAMSci.group.shef.ac.uk/CI_content/FRP/AS-CCC2008.pdf · BASALT FRP for STRENGTHENING of RC BEAMS A. Serbescu M. Guadagnini, K. Pilakoutas and

CCC 2008 - Porto Basalt FRP for RC Strengthening

BASALT FRP for STRENGTHENING

of RC BEAMS

A. Serbescu

M. Guadagnini, K. Pilakoutas and N. Taranu


Outline

1. Introduction

2. Basalt Fibres

3. Flexural strengthening with BFRP

4. Assessment of debonding models

5. Shear strengthening with BFRP

6. Conclusions


Miss Futura

FR

P

STEEL

Mr. Traditional

Photo - Urs Meier, EMPA

Strength Versatility Non magnetic Durability

Fibre Polymer FRPCorrosion…

Conductivity…

Handling… + = &

ε [%]1 2 3

500

1000

1500

2000

2500

σ [MPa]

Steel

CFRP

??

!!

vs.

STEEL FRP


STRENGTHENING of RC BEAM by EBR

Plate or sheets Strips

FLEXURAL EBR SHEAR EBR

U - shape Side bonded


Price of

Basalt fibres

≈

Carbon fibre / 15

Non-toxic and

easier to recycle

than glass4840 MPa

HIgh Impact

and Fire

ResistanceHigh chemical

durability in water, salts,

alkalis and acids

Source: BFCMTD - China

BFRP

POTENTIAL BENEFITS


FLEXURAL STRENGTHENING with BFRP

Beam Geometry

150

250

33

210

PΦ8@100Φ6

Φ

100

2300/2

Reinforcement (Steel & FRP) Ratio (%)

edst

ren

gth

en

serv

ice

ened

un

stre

ng

th

serv

ice

/ δδ

0.75

1

1.25

1.5

1.75

2

2.25

2.5

2.75

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6

Deflection (mm)

Pu

lt(K

N)

0

50

100

150

200

250

0 10 20 30 40

strengthened

unstrengthened

FRP Area

0 mm2

200 mm2

400 mm2

600 mm2

800 mm2

1000 mm2


0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

0 0.005 0.01 0.015 0.02 0.025 0.03

FRP Reinforcement Ratio

ρs=0

ρs=2

ρs=1

ρs=0.7

ρs=1.5

ρs=0.5

ρs=2.5

FRP Ratio

Norm

aliz

ed m

om

ent

FR

P R

atio

Steel Ratio

0

0.005

0.01

0.015

0.02

0.025

0 0.005 0.01 0.015 0.02 0.025

Maximum FRP ratio

Minimum FRP ratio

FLEXURAL STRENGTHENING with BFRP


ASSESSMENT of ANCHORAGE DEBONDING MODELS

Rip-off

Peel-off

End Shear Failure

Shear Crack

Anchorage Debonding


PREDICTIONS of SHEAR DEBONDING FORCE


0.240.251.05Taljsten - 1996

0.180.220.86Iso - JCI, 2003Fracture Mechanics

0.230.301.34Janzse - fib, 2001

0.240.331.40Smith and Teng - 2002

0.240.321.36Blaschko - fib, 2001

0.340.341.02Matthys - fib, 2001Shear capacity

0.180.191.03Naaman - 2003

0.220.170.77ACI - 2002Empirical

COVStd. Deviation - sAverage - mModelApproach

Variability of the assed models

PREDICTIONS of SHEAR DEBONDING FORCE


Experimental study on SHEAR BFRP

Tensile test

Fixed grip

Mobile end

BFRP Strip

BFRP Strip Testing rig

Results:

Ef = 28 GPa – test

Ef = 29.8 GPa – design

ff = 1050 MPa – test

ff = 1030 MPa – design


RC beam test - CFRP Flexural Plated RC beams

• BFRP strips U – shaped

(235x20)mm

• RC beam strengthened

only in flexure

150

250 2 φ 6

2 φ 20

L = 2.5 m

Tested Beam

Control Beam



CB - Concrete rip-off failure at 134KN

TB - Peel-off failure at 171KN

0

20

40

60

80

100

120

140

160

180

0 2 4 6 8 10 12 14 16 18 20

Loa

d (

KN

)

Deflection (mm)


0

20

40

60

80

100

120

140

160

180

0 5 10 15 20

Loa

d (

KN

)

Deflection (mm)

CB

TB

ULS


µε

0

20

40

60

80

100

120

140

160

180

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

67

69

75

Load (

KN

)

Strain in BFRP strips (µε)



CONCLUSIONS

√ BFRP as flexural reinforcement – for moderate requirements

- No accurate debonding model

- Shear capacity strongly influences the plate anchorage debonding

- Potential model for accurate predictions - fracture mechanics + shear

capacity

√ BFRP as shear reinforcement


Thank you!Thank you!Thank you!Thank you!Thank you!Thank you!Thank you!Thank you!

Documents

BASALT FRP for STRENGTHENING of RC BEAMSci.group.shef.ac.uk/CI_content/FRP/AS-CCC2008.pdf · BASALT FRP for STRENGTHENING of RC BEAMS A. Serbescu M. Guadagnini, K. Pilakoutas and