eitli titi fexperimental investigation of hfrp composite beams · eitli titi fexperimental...
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E i t l I ti ti fExperimental Investigation of HFRP Composite Beams
Authors:Hiroshi Mutsuyoshi, Nguyen Duc Hai, Kensuke Shiroki, Thi A i th All M lThiru Aravinthan, Allan Manalo
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Presentation Outline
Flexural Test ofHFRP Beams
Flexural Test of HFRP‐NSC
Part 1 Part 2
Composite Beams
P t 3
ConclusionsFlexural Test of HFRP‐UHPFRC
Composite Beams
Part 3
Composite Beams
2FRPRCS‐10, Tampa, Florida2011.04.02
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Presentation Outline
• Part 1: Flexural Test of HFRP Beams• Part 2: Flexural Test of HFRP‐NSC Composite Beams
• Part 3: Flexural Test of HFRP‐UHPFRC Composite BeamsComposite Beams
3FRPRCS‐10, Tampa, Florida2011.04.02
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Flexural Test of HFRP Beams: Introduction
R d d i i dT l b f b id i J Rust and damage in girders (Kuretsubo Bridge)
Total number of bridges in Japan
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Flexural Test of HFRP Beams: Introduction
High specific strength/stiffnessHigh durability
Fiber Reinforced Polymers (FRP)
GFRPHigh durabilityLow life‐cycle costsCorrosion resistanceLightweight
CFRP
Why hybrid FRP?
Hybridization with carbon fibers of glass fiber composites is known to enhance fatigue performance and environmental resistance compared to all‐glass composites.resistance compared to all glass composites.
The failure strain of carbon fiber appears to be greater in a hybrid than in an all‐carbon g yfiber composite structure.
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Flexural Test of HFRP Beams: Experiments
A b f i t t d d f i t b diA number of specimen were tested under four point bending
Beam elevation
Flange
CF 0GF 0/90CSMGF ±4533 plies
(CF/GF)18 plies(GF)
Web
(CF/GF) (GF)
Cross section Layer composition
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Flexural Test of HFRP Beams: Experiments
M h i l ti f t i l
Parameters NotationCFRP0°
GFRP0/90°
GFRP±45°
GFRPCSM
Volume fraction V (%) 55 53 53 25
Mechanical properties of materials
Volume fraction Vf (%) 55 53 53 25
Young’s modulusE11 (GPa) 128.1 25.9 11.1 11.1
E22 (GPa) 14.9 25.9 11.1 11.1
Sh d l G 5 5 4 4 10 9 4 2Shear modulus G12 5.5 4.4 10.9 4.2
Poisson’s ratio ν12 0.32 0.12 0.29 0.31
Volume contentFlange (%) 33 17 41 9
Web (%) 0 43 43 14
Effective mechanical properties of HFRP laminates
Parameters Flange Web
Compressive strength (MPa) 394 299
Tensile strength (MPa) 884 185Tensile strength (MPa) 884 185
Young’s modulus (GPa) 49.6 17.8
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Flexural Test of HFRP Beams: Experiments
H d li J kHydraulic Jack
Load Cell
Spreader Beam
Safety rigSafety rig
SupportSupport
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Flexural Test of HFRP Beams: Results
250
150
200
250
oad (kN)
150
200
250
load
(kN)
0
50
100
App
lied l
Exp.FEA
0
50
100
App
lied
Exp. (TF)Exp. (BF)FEA (TF)FEA (BF)
0 10 20 30 40 50 60
Mid‐span deflection (mm)
0
‐8000 ‐6000 ‐4000 ‐2000 0 2000 4000 6000 8000
Strain in top/bottom flange at mid‐span (m)
Crushing of fibers and delamination Closer view of delamination
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Presentation Outline
• Part 1: Flexural Test of HFRP Beams• Part 2: Flexural Test of HFRP‐NSC Composite Beams
• Part 3: Flexural Test of HFRP‐UHPFRC Composite BeamsComposite Beams
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Flexural Test of HFRP‐NSC Composite Beams: Introduction
εc2Concrete slab
εc1 Neutral Axis‐2
Neutral Axis‐1
εεt1εc1 ≈ εt1
εt2εc2
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Flexural Test of HFRP‐NSC Composite Beams: Experiments
P/210 mm θ u-bolts spaced 150 mm o.c. between stiffeners
P/26 mm θ ties spaced 300 mm o.c. at shear span and 150 mm o.c. between loading points
Hydraulic jack
1000 mm300 mm 1000 mm 300 mm1000 mm
Length of HFRP beam: 3 6 m (clear span: 3 m)
a. Specimen FRP-conc 3 dimensions and loading system3600 mm
400 mmCast-in-place
concrete deck Length of HFRP beam: 3.6 m (clear span: 3 m)Shear connectors: 10 mm diameter high strength steel u‐bolts and epoxy resinSteel u‐bolts: spaced at 150 mmNSC slab: 100 mm thick; 400 mm wideS l i f 16 di
100 mm
10 mm θu-bolts
16 mm θlongitudinal bars
d 90
16 mm θlongitudinal bars
spaced 90 mm o.c.
Steel reinforcements: 16 mm diameterMean cylinder strength of NSC (14 days): 32 MPaLateral steel ties: 6 mm diameter spaced at 300 mm in the shear span and spaced at 150 mm in the flexural span95 mm
250 mmHybrid FRP girder
spaced 90 mm o.c.
Draw wire displacement transducerLVDT
p
b. Cross section of specimen FRP-conc 3
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Flexural Test of HFRP‐NSC Composite Beams: Results
500 427 KNFailure load
300
400
KN
196 KN
Failure load
200
300
Load
, K
196 KNcracking of concrete
0
100 FRP-1FRP-conc 3
0 20 40 60 80 100Deflection, mm
L d d id d fl tiLoad and mid-span deflection
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Flexural Test of HFRP‐NSC Composite Beams: Failure Mode
Compression failure of NSC slab Shear failure of HFRP beam
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Presentation Outline
• Part 1: Flexural Test of HFRP Beams• Part 2: Flexural Test of HFRP‐NSC Composite Beams
• Part 3: Flexural Test of HFRP‐UHPFRC Composite BeamsComposite Beams
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Flexural Test of HFRP‐UHPFRC Composite Beams: Introduction
UHPFRC = Ultra‐High Performance Fiber‐Reinforced Concrete“SUQCEM ‐ SUper High Quality CEmentitiousMaterial”
High strengthHigh durabilityReduce weight of structure, etc
Conventional concreteUHPFRC
h2h h2h1
h1
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Flexural Test of HFRP‐UHPFRC Composite Beams: Materials
UHPFRC
Mix Proportions of UHPFRC (JSCE 2006)
Air content (%)Unit quantity (kg/m3) Steel fiber
(kg/m3)Water Premix cement Sand W.R. Ad i tAdmixture
2.0 205 1287 898 32.2 137.4
Mechanical properties of UHPFRC
Compressive strength2
Tensile strength2
Young Modulus 2(N/mm2) (N/mm2) (kN/mm2)
173 14.3 48.6
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Flexural Test of HFRP‐UHPFRC Composite Beams: Test Variables
T t i bl
BeamShear
connectorEpoxy bonding
Width of UHPFRC slab (mm)
Thickness of UHPFRC slab (mm)
Embedded length of bolt (mm)
†B 135 50 Bolt M16 135 50 35
Test variables †B = Bolts; ††SA = Slab Anchors; †††BE = Bolts and Epoxy
†B‐135‐50 Bolt M16 ‐ 135 50 35††SA‐135‐50 Slab anchor M10 ‐ 135 50 35†††BE‐95‐50 Bolt M16 ○ 95 50 35
†††BE‐135‐35 Bolt M16 ○ 135 35 30††††††BE‐135‐50 Bolt M16 ○ 135 50 35
Unit: mmSpecimen layouts
B (BE)‐135‐50 Unit: mm
Configurations with bolts
BE‐95‐50
3 3
Unit: mm
S 3 0
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BE‐135‐35 Unit: mm
Configurations with slab anchors
SA‐135‐50
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T t t
Flexural Test of HFRP‐UHPFRC Composite Beams: Test Setup
Safety RigStiffener
Test setup
1000 1000 10001000 1000 1000
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Flexural Test of HFRP‐UHPFRC Composite Beams: Test Results
400450500
BE-135-50
BE 95 50
Load‐deflection relationship Failure mode
15%
200250300350400
d (k
N)
SA-135-50
B-135-50
BE-95-50
BE-135-35
50100150200
Loa
Control specimen
00 20 40 60 80
Deflection (mm)
Compression failure of UHPFRC slab (B/BE specimen series)
Increase flexural strength and stiffnessHFRP UHPFRC
HFRP flange delamination failure(SA‐135‐50)
Increase flexural strength and stiffnessPrevent fracture of HFRP in the compressive flange
HFRP‐UHPFRC Composite girder
Shear connectors
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combined with adhesive bonding
Increase stiffness
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Strain distribution at mid‐span section
Flexural Test of HFRP‐UHPFRC Composite Beams: Test Results
Strain distribution at mid span sectionWithout
epoxy bonding
250
300
350m
)100 kN
200 kN
300 kN 250
300
350
m)
100 kN
200 kN
232 kN (Failure)
100
150
200
250
Sect
ion
dept
h(m
m
400 kN
437 kN (Failure)
Headed bolts100
150
200
250
Sect
ion
dept
h (m
m ( )
Shear anchors
With
0
50
-6000 -3000 0 3000 6000 9000 12000Axial strain (μ)
0
50
-6000 -3000 0 3000 6000 9000 12000Axial strain (μ)
350epoxy bonding Nonlinear strain
distribution initiated at the bottom of the HFRP compressive fl
Slipping at the interface between the UHPFRC slab 200
250
300
350
epth
(mm
)
100 kN
200 kN
300 kN
400 kN
470 kN (failure)flange and the HFRP
beam
Linear strain distribution through
Full composite action until the0
50
100
150
Sect
ion
de
( )
Headed bolts
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the cross‐section up to failure
action until the final failure
0-6000 -3000 0 3000 6000 9000 12000
Axial strain (μ)
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St i Di t ib ti i HFRP T Fl B lt H l
Flexural Test of HFRP‐UHPFRC Composite Beams: Test Results
Strain gages
St i
Strain Distribution in HFRP Top Flange near Bolt Hole
‐1000
‐500
0
100kN ‐400
‐200
0
100kN
Strain gages Strain gages
3500
‐3000
‐2500
‐2000
‐1500
Strain (μ
)
100kN
200kN
300kN
400kN
437kN‐1000
‐800
‐600
400
Strain (μ
)
100kN
200kN
300kN
381kN
‐4500
‐4000
‐3500
‐6 ‐4 ‐2 0 2 4 6
Distance from bolt hole (mm)
‐1400
‐1200
‐6 ‐4 ‐2 0 2 4 6
Distance from bolt hole (mm)
(a) Specimen without epoxy
( )
(b) Specimen with epoxy
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UHPFRC
Flexural Test of HFRP‐UHPFRC Composite Beams: Comparisons
UHPFRC
s
0.85f’ck BeamPredicted failure load, kN
Actualfailure load, kN
Predicted/actual failure mode
Flexural Test Results at Failure of HFRP‐UHPFRC Composite Beam
Compressive
stress kN kN
B-135-50 ⎯ 438 Compression – UHPFRC
SA-135-50 ⎯ 232 Delamination – HFRP top flangeBE-95-50 384 382 Compression – UHPFRCBE 135 35 411 394 C i UHPFRC
Bi‐linear relationship for UHPFRC (JSCE 2006)Strain0.85f’ck/Ec 0.0035
600BE-95-50 (Experiment)
BE-135-35 411 394 Compression – UHPFRCBE-135-50 481 470 Compression – UHPFRCHFRP-NSC ⎯ 427 Compression – NSC
FlangeWeb
fFt
E
HFRP
300
400
500(k
N)
BE 95 50 (Experiment)BE-95-50 (Analysis)BE-135-35 (Experiment)BE-135-35 (Analysis)BE-135-50 (Experiment)BE-135-50 (Analysis)
Stress
fW
fWt
EW
EF
0
100
200Loa
d (
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Strain
fFc
fWc 00 10 20 30 40 50 60 70
Deflection (mm)
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Conclusions
1) The investigated HFRP beams behave linearly under flexural load and failed suddenly without forewarning. The failure was crushing of fibers near the loading point due to load concentration followed by the d l i i f h i fl b h i f f CFRPdelamination of the compressive flange between the interface of CFRP and GFRP layers.
2) Composite beams consisting of HFRP beams and concrete topping slabs i ifi l i h i fl l iff d ff i l ili hsignificantly improve their flexural stiffness and effectively utilize the superior properties of the HFRP materials.
3) The use of UHPFRC slab is more effective than NSC slab in terms of t t l tiff d i htstructural stiffness and weight.
4) HFRP‐UHPFRC composite beams with headed bolt shear connectors provide considerable stiffness and strength increase compared with HFRP b ith t t t i l bbeams without concrete topping slab.
5) Composite beams with epoxy bonding between the UHPFRC slab and HFRP beam top flange showed an approximately 15% increase in flexural tiff th b t d ith b lt lstiffness than beams connected with bolts only.
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