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CCC 2008 - Porto Basalt FRP for RC Strengthening
BASALT FRP for STRENGTHENING
of RC BEAMS
A. Serbescu
M. Guadagnini, K. Pilakoutas and N. Taranu
CCC 2008 - Porto Basalt FRP for RC Strengthening
Outline
1. Introduction
2. Basalt Fibres
3. Flexural strengthening with BFRP
4. Assessment of debonding models
5. Shear strengthening with BFRP
6. Conclusions
CCC 2008 - Porto Basalt FRP for RC Strengthening
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
CCC 2008 - Porto Basalt FRP for RC Strengthening
STRENGTHENING of RC BEAM by EBR
Plate or sheets Strips
FLEXURAL EBR SHEAR EBR
U - shape Side bonded
CCC 2008 - Porto Basalt FRP for RC Strengthening
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
CCC 2008 - Porto Basalt FRP for RC Strengthening
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
CCC 2008 - Porto Basalt FRP for RC Strengthening
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
CCC 2008 - Porto Basalt FRP for RC Strengthening
ASSESSMENT of ANCHORAGE DEBONDING MODELS
Rip-off
Peel-off
End Shear Failure
Shear Crack
Anchorage Debonding
CCC 2008 - Porto Basalt FRP for RC Strengthening
PREDICTIONS of SHEAR DEBONDING FORCE
CCC 2008 - Porto Basalt FRP for RC Strengthening
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
CCC 2008 - Porto Basalt FRP for RC Strengthening
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
CCC 2008 - Porto Basalt FRP for RC Strengthening
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
Experimental study on SHEAR BFRP
CCC 2008 - Porto Basalt FRP for RC Strengthening
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)
Experimental study on SHEAR BFRP
0
20
40
60
80
100
120
140
160
180
0 5 10 15 20
Loa
d (
KN
)
Deflection (mm)
CB
TB
ULS
CCC 2008 - Porto Basalt FRP for RC Strengthening
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)
Experimental study on SHEAR BFRP
CCC 2008 - Porto Basalt FRP for RC Strengthening
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
CCC 2008 - Porto Basalt FRP for RC Strengthening
Thank you!Thank you!Thank you!Thank you!Thank you!Thank you!Thank you!Thank you!
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