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““SHEARBAND:SHEARBAND:Verification of a Novel Punching Shear Reinforcement System for Flat Slabs”

Kypros PilakoutasKypros Pilakoutas --ChristianaChristiana Ioannou (speaker)Ioannou (speaker)CentreCentre for Cement and Concretefor Cement and Concrete-- The University of SheffieldThe University of Sheffield

http://www.shef.ac.uk/~ccc/

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ProblemProblemSolutionsSolutionsShearbandShearband reinforcementreinforcementExperimentsExperimentsResultsResultsConclusionsConclusions

OutlineOutline

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Anchorage:Anchorage: The problem with The problem with Punching Shear ReinforcementPunching Shear Reinforcement

Shear headsShear heads

StudStud--railrail

ShearbandShearband

Conventional Conventional Reinforcement Reinforcement

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ΤΤhe he shearband shearband on on top of the upper top of the upper flexural flexural reinforcementreinforcement

50 50

planplan

Thickness=0.8mm

ShearbandShearband

100 100

13525.4 mm

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1) maximum effective depth

2) easy placement

3) bond

4) design based on Codes

Advantages

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TestsTests

Control Slab (PSSA)Control Slab (PSSA)

7 Slabs (PSSB7 Slabs (PSSB--PSSG) PSSG)

Slab with holes (PSSHSlab with holes (PSSH))

Further work on slabs with holesFurther work on slabs with holes

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SS1 SS2SS3

SS4

SS5

SS6

SS7

SS8

Distribution of Distribution of ShearbandShearband

SS1 SS2

SS3SS4

SS5

SS6

SS7

SS8

SS1 SS6

SS7

SS12

SS1 SS6

SS7 SS12

SS1 SS6

SS7 SS12SS9 SS10

PSSB,C

PSSF PSSG

PSSEPSSD

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Slab PSSHSlab PSSH SS1 SS6

SS7 SS12

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PSSB

PSSD PSSE

PSSC

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PSSF

PSSH

PSSG

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Control SlabControl Slab

PSSAPSSA

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PSSCPSSC

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ResultsResultsSlab fc (MPa) Failure Load

(kN)

Maximum Deflection

(mm)

PSSA 32.3 454 11.45

PSSB 39 560 25.35

PSSC 41.2 560 24.11

PSSD 42.2 560 21.39

PSSE 43.4 573 26.27

PSSF 43.4 598 30.19

PSSG 38.0 590 27.78

PSSH 38.0 544 17.44

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LoadLoad--DeflectionDeflectionL

oad

(kN

)

0

100

200

300

400

500

600

5 1010 15 20 25 30

PSSEPSSBPSSA

Deflection (mm)

D850

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LoadLoad--Deflection Deflection

Deflection (mm)

Load

(kN

)

0

100

200

300

400

500

600

5 10 15 20 25 30 35 40

PSSH@D600PSSH@D850PSSG@D600 PSSG@D850

D600

D850

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LoadLoad--Strain in Flexural Strain in Flexural ReinforcementReinforcement

Lo a

d (k

N)

Strain (microstrain)

0

100

200

300

400

500

600

2000 4000 6000 8000 10000 12000 14000 16000 18000 20000

PSSAPSSBPSSCPSSD

S1S1

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LoadLoad--Strain in Strain in ShearbandShearband

Strain (microstrain)

Loa

d (k

N)

0

100

200

300

400

500

600

500 1000 1500 2000 2500 3000 3500

SS4SS10

Slab PSSE

S4S4

S10S10

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ConclusionsConclusions

The Shearband:Prevents brittle punching shear failure and leads to ductile behaviourFast and easy fixing; placed on top of main reinforcementAnchors over the top layer of main reinforcementMeets the criteria of International Codes of Practice

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Future WorkFuture Work