EitlI titi fExperimental Investigation of HFRP Composite Beams · EitlI titi fExperimental Investigation of HFRP Composite Beams Authors: Hiroshi Mutsuyoshi, Nguyen DucHai, Kensuke

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

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


• 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


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


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.


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



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



H d li J kHydraulic Jack

Load Cell

Spreader Beam

Safety rigSafety rig

SupportSupport


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


Flexural Test of HFRP‐NSC Composite Beams: Introduction

εc2Concrete slab

εc1 Neutral Axis‐2

Neutral Axis‐1

εεt1εc1 ≈ εt1

εt2εc2

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


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

2011.04.02 13FRPRCS‐10, Tampa, Florida

Flexural Test of HFRP‐NSC Composite Beams: Failure Mode

Compression failure of NSC slab Shear failure of HFRP beam

2011.04.02 14FRPRCS‐10, Tampa, Florida

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

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

FRPRCS‐10, Tampa, Florida 172011.04.02

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

FRPRCS‐10, Tampa, Florida 18

BE‐135‐35 Unit: mm

Configurations with slab anchors

SA‐135‐50

2011.04.02

T t t

Flexural Test of HFRP‐UHPFRC Composite Beams: Test Setup

Safety RigStiffener

Test setup

1000 1000 10001000 1000 1000


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


combined with adhesive bonding

Increase stiffness

2011.04.02

Strain distribution at mid‐span section


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


the cross‐section up to failure

action until the final failure

0-6000 -3000 0 3000 6000 9000 12000

Axial strain (μ)

2011.04.02

St i Di t ib ti i HFRP T Fl B lt H l


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


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 (


Strain

fFc

fWc 00 10 20 30 40 50 60 70

Deflection (mm)

2011.04.02

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.


Documents

EitlI titi fExperimental Investigation of HFRP Composite Beams · EitlI titi fExperimental Investigation of HFRP Composite Beams Authors: Hiroshi Mutsuyoshi, Nguyen DucHai, Kensuke