the use of thermoplastic frp cit shrif tcomposites as...

The use of Thermoplastic FRP C it Sh R i f t

The use of Thermoplastic FRP C it Sh R i f tComposites as Shear Reinforcement

for Concrete StructuresComposites as Shear Reinforcement

for Concrete Structures

Thanongsak ImjaiThanongsak ImjaiMaurizio GuadagniniMaurizio GuadagniniKypros PilakoutasKypros Pilakoutas

Construction Innovation Research GroupDepartment of Civil and Structural

© 2007 The University of SheffieldWestern Bank, Sheffield S10 2TN, UK

ACIC’07University of Bath, UK, April 2007

© 2006 The University of Sheffield

Department of Civil and Structural Engineering

OutlineOutline

•• Why thermoplastics?Why thermoplastics?

•• Experimental programmeExperimental programme

Experimental resultsExperimental results•• Experimental resultsExperimental results

•• ConclusionsConclusionsConclusionsConclusions



Why thermoplastics?Why thermoplastics?

••End anchoragesEnd anchorages

••Element connectionElement connectionElement connectionElement connection

••Shear reinforcementShear reinforcement



Why thermoplastics?Why thermoplastics?

•Thermosetting FRP’s can only be pre-bent at the factory

•Thermoplastic FRP’s could offer a valid psolution for on-site bending of reinforcement



Thermoplastic linksThermoplastic linkspp

GFRP thermoplastic strip (GFRP thermoplastic strip (1010xx33mm)mm)

PropertiesTensile strength (MPa) 720

Tensile modulus (GPa) 28

Ultimate strain (%) 1.9

Glass content (%v/v) 35

Density (g/cm3) 1.48




y (g )

Thermoplastic linksThermoplastic links

•• Bending processBending processGFRP Shear reinforcementGFRP Shear reinforcement

•• Bending processBending processBeam cage

Manufacturing of FRP links using thermoplastic composite strips



© 2006 The University of Sheffield ACIC 2007

Thermosetting barsThermosetting bars

GFRP Flexural reinforcementGFRP Flexural reinforcement

φ = 16 mmE = 60 GPaE 60 GPaff = 1000 MPa

φ = 13.5 mmE = 45 GPaE = 45 GPaff = 700 MPa



Test set-upTest set-up

ID 1A 1B 2A 2B 3A 3B 4A 4B 5A 5B 6A 6Bρ 1 22 % 1 30 %ρl 1.22 % 1.30 %

ρw0.24 0.37 0.41 0.18 0.24 0.36 0.30 0.48 0.24 -

/t 2 4 5 4 4 4 5 4 4 4 5



r/t 2 4 5 4 4 4 5 4 4 4 5 -

Strain measurementsStrain measurements



Deflection measurementsDeflection measurements



Experimental resultsExperimental results



Experimental resultsExperimental resultsN

) 80

hear

(kN

602B

4B

5B

Sh

401B3B

6B No shear reinforcement

20

6B No shear reinforcement

(%)0.0 0.1 0.2 0.3 0.4 0.5 0.6

0



ρw (%)

Experimental resultsExperimental results

0ρw = 0

ρw = 0.18%s = d (219)s = d (219)

ρw = 0.36%s = 0.5d (109)



Max crack width < 0.5mm @ SLMax crack width < 0.5mm @ SL

Analytical predictionsAnalytical predictionskN

) 80ISE 99

V The

o (k

506070 ISE-99

ACI-440.1R-06ISE-modified ACI difi d

valu

es, V

304050 ACI-modified

edic

ted

v

102030

Experiment V (kN)0 10 20 30 40 50 60 70 80

Pre

0



Experiment, Vexp (kN)

ConclusionsConclusions

••Thermoplastics can offer a viable solution Thermoplastics can offer a viable solution ppfor onfor on--site bendingsite bending

Thermoplastic links seem toThermoplastic links seem to offer adequateoffer adequate••Thermoplastic links seem to Thermoplastic links seem to offer adequate offer adequate resistance and meet serviceability resistance and meet serviceability requirements (diagonal crack width)requirements (diagonal crack width)requirements (diagonal crack width)requirements (diagonal crack width)

••Durability?Durability?yy

••Bend capacity?Bend capacity?




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