DIANA在纤维混凝土中的应用英文

StructuralapplicationsofFiberReinforcedConcretesimulatedwithDIANAGiuseppe

Tiberti,

Giovanni

PlizzariPhD-DICATAM-DepartmentofCivil,Environmental,ArchitecturalEngineeringandMathematics,UniversityofBresciaUniversityofBrescia,ITALYgiuseppe.tiberti@unibs.itgiovanni.plizzari@unibs.itResearch

group

Several

research

works

are

on-going

attheUniversityof

Brescia

The

research

groupledbyprof.G.A.Plizzariisdevelopinga

noticeableresearch

regarding

innovativecementitiousmaterials

for

usein

structuralapplications

The

aforementioned

research

groupis

currentlycomposed

by:-

GiovanniPlizzari,Full

professor

ofstructuralengineering;-

FaustoMinelli,PhD,

Assistantprofessorof

structural

engineering;-

GiuseppeTiberti,PhD,

Assistant

professor

of

structural

engineering

Furthermore,

several

PhD

Students

as

well

as

PhD

Fellowsareinvolvedin

theoverallactivitiesofthegroup

Itis

worthwhilenoticingthattheresearchdeveloped

concerning

FiberReinforced

Concretes

(FRCs)in

thelasttwo

decades

byprof.Plizzariandhisgroup

was

an

importantcontributionto

specificrulesand

recommendationscurrently

presentin

the

section

devotedtodesign

of

FRCstructuresin

thenew

Model

Code

20102/50Research

groupContentsAmongtheinnovativematerials

underinvestigationthispresentationwillbefocused

on

FRCPart

1:

Introduction

on

FRCPart

2:

Examples

concerningtheresearch

on-going

attheUniversity

ofBrescia

on

FRC

by

means

of

experimentalinvestigationas

well

as

by

meansof

numerical

simulationcarriedout

by

means

of

DIANAPart

3:

Main

concepts

regarding

the

necessary

procedure

for

includingfibrousreinforcementcontribution

inthecrack

modelscurrentlyimplementedinDIANAPart

4:

Numerical

simulations

of

precast

tunnellining

underthesevere

loadsapplied

by

Tunnel

Boring

Machines

(TBMs)duringtheexcavation

process3/50ContentsFiber

Reinforced

ConcreteMany

structural

and

non

structuralelements

are

nowadays

designedand

reinforced

with

FRC,

asPARTIAL

or

TOTAL

substitution

ofconventional

reinforcement.4/50Part

1:

Introduction

to

FRCTypes

of

FibersAluminium

fibersGlass

fibersSteel

fibersPolypropylen

fibers5/50Part

1:

Introduction

to

FRCFiber

Reinforced

Concrete

EffectsFiberContentVf

1%

(w)res•

Durability•

Minimum

Reinforcement

(N,

Me

V)•

Crack

Control•

Fatigue•

Enhancedtensionstiffeningandlimitationofdeflectionat

SLS•Shrinkage(restrainedbasically)•Post-Crackingtoughness•

D

Regions

(deep

beams,spalling,bursting,splitting)6/50Part

1:

Introduction

to

FRCStrain

Softening-Strain

HardeningPPPPPP(a)(b)Small

fibre

volume

fraction

(0.2

–

2%):

the

FRC

shows

a

softening

behaviour,but

it

is

characterised

by

a

residual

strength

as

well

as

a

greater

toughness.Higher

fibre

volume

fraction

(2

–

8%):

the

behaviour

can

become

hardening,duetothepresenceofmultiplecracking.NotchedSpecimensarenotgoodforstrainhardeningmaterials.7/50Part

1:

Introduction

to

FRCFrom

material

to

structural

behaviorNaaman,

A.E.

and

Reinhardt,

H.

(eds),

High

Performance

fiber

reinforced

cement

composites–HPFRCC4

RILEMProceedings,

PRO30,

Rilem

Publications

S.A.R.L.,

Bagneux,

France,

2003.8/50Part

1:

Introduction

to

FRCStructural

analysis:

RC

vs.

FRCRCFRCIn

RC

structuresthe

response

can

be

accepted

aslinearuptoyieldingofthe

reinforcementIn

FRC

structurestheresponseismarkedly

non

linearPerforming

Non

Linear

analysesisnecessary9/50Part

1:

Introduction

to

FRCFRC

Modelling

under

tensionBefore

CrackingAfter

Crackingfctmatrix

+

fibresPPEofibresmatrix1wcrFractureenergyin

FRCelementsismainly

provided

by

fiberspull-out10/50Part

1:

Introduction

to

FRCFRC

typical

fracture

tests•

Generallya

performance

approachis

chosen:thematerial

hastobe

tested

as

composite,

becausethemechanical

responsecannot

be

properlyidentifiedby

knowingthemix

design

andthemechanicalcharacteristicsof

each

componentUNIAXIAL

TENSION

TESTBENDING

TEST11/50Part

1:

Introduction

to

FRCCMOD-controlled

testsSeveral

standards,

concerning

the

characterization

of

FRC,

are

based

onCMOD-controlled

tests

on

notched

beams

loaded

with

a

three

(3PBT)

orfour

point

test

(4PBT).CMOD

is

the

Crack

Mouth

Opening

Displacement.

Basically,

CMOD

is

themouth

crack-opening

of

the

notchwhichincreases

during

thetest.bCTODCTODDepthofthenotchGAUGECMODCMODLGAUGECTOD

is

the

Crack

Tip

Opening

Displacement.

Basically,

CTOD

is

thecrack-opening

at

the

notchtip.12/50Part

1:

Introduction

to

FRCFRC

classification

(3PBT)EN

14651hsp

=

125

mmb

=

150

mm3Fj

lf

R,jLinearstressdistribution,2bh2Nominalresidualpost-crackingstressessp13/50Part

1:

Introduction

to

FRCAnalysis

of

a

masonry

wall

with

SFRM

coating:effects

of

coating

shrinkage

on

the

wall

capacityFree

bodydiagramSpecimengeometryandloadset-up3-D

mesh

(Diana

9.4.4)VVV/2Hbeam

elements

forsimulatingsteelconnectors

betweencoating

and

masonrybrick

elements

forinterface

elements

forsimulating

the

non-linearbehavior

of

masonry-to-coating

interfacesimulatingmasonry

andSteel

Fiber

ReinforcedMortar

coating14/50Part

2:

Examples

of

FRC

structural

applications

investigatedSimulation

of

a

Steel

Fiber

Reinforced

Concreteunderground

water

tank3-D

model

(Diana

9.3)Structureoverviewandloadset-up¼

tankSteel

60mmpipeTypicalloadingconditionsbrickelementsGroundpressureontheoutersurfaceOnenodetranslationelements15/50Part

2:

Examples

of

FRC

structural

applications

investigatedSteel

Fiber

Reinforced

Concrete

thin

slabs3-D

modelSimplysupportedslabgeometryandloadset-upFourpointbendingtestFracture

behavior

ofSFRSCC

modeled

bythe

“total

strainrotating

crack

model”(smeared

crackNo-tension

springelements

formodeling

supportsapproach)16/50Part

2:

Examples

of

FRC

structural

applications

investigatedSlabs

on

grade

under

shrinkage

effectNumerical

model:3D

numerical

model,

because

of

symmetry,

one-quarter

of

slab

was

simulated.Numerical

results,

typical

slab

response

under

shrinkage

effect:Distributionofverticaldisplacement

[mm]

at

first

crack,8.5

days:curlingeffect.17/50Part

2:

Examples

of

FRC

structural

applications

investigatedSteel

Fiber

Reinforced

Concrete

pipesTypicalgeometryandloadset-up2-D

model2-D8-nodeselements18/50Part

2:

Examples

of

FRC

structural

applications

investigatedConventional

excavated

tunnel

with

cast

in

placeFRC

tunnel

liningMesh

refinementBenchCold

jointInvert19/50Part

2:

Examples

of

FRC

structural

applications

investigatedPrecast

FRC

tunnel

lining

elements20/50Part

2:

Examples

of

FRC

structural

applications

investigatedIncluding

fibrous

reinforcement

contribution

in

NLFEA

The

main

advantage

of

FRCwithrespectto

a

traditionalplainconcreteisthe

noticeable

improvement

of

the

post-cracking

response

because

offibrousreinforcementcontribution

In

orderto

includethiscontributionseveral

crack

models

arecurrentlyimplementedin

DIANA:-multi-directionalfixedcrack

model;-totalstrainfixedcrack

model;-totalstrainrotating

crack

Asa

general

recommendation,itis

always

better,ifitis

possible,to

verifyandvalidatethenumerical

modelwithexperimentaltests

available

inliteratureonstructuralelementssimilarof

that

underinvestigation21/50Part

3:

Main

concepts

modelling

FRC

with

DIANAPost-cracking

contribution

in

NLFEA

The

post-crackinglaw

forusein

numericalanalysesis

generallyobtainedby

means

of

the

inverse-analysis

method:DiscretecrackapproachSmearedcrackapproachfctfct+Ecs1ww1Post-cracking

law,Part

3:

Main

concepts

modelling

FRC

with

DIANAwcCTODmPre-cracking

law,

--w22/50Post-cracking

contribution

in

NLFEA

Typicalresultsobtained

by

means

ofa

discrete

and

smeared

approach

byusingDIANA:765432103PBT-EN14651-SFRC0.25MExperimentalMeanexperimentalSFRC0.25MDiscreteapproachSFRC0.25MSmearedapproach00.511.522.533.5CTODm

[mm]23/50Part

3:

Main

concepts

modelling

FRC

with

DIANANon-linear

-

numerical

analysesSeveralexperimentaltestsonSFRCspecimenswerenumericallysimulatedinordertocheckthepreviouslymentionedissuesByusingDIANAandthetotalstraincrackmodelthefollowingloadingconditionsweresuccessfullysimulated(goodagreement)4PBTsSplittingtestsFlexuralandsplittingtestsonfull-scalesegmentswith/withoutcurvaturerespectively109NumericalCrackPatterns876LVDT2LVDT25ExperimentalCrackPatterns43SFRC50/0,75-Vf=0,51%:FEAExperimental21000,20,40,60,811,2ε,

LVDT[‰]24/50Part

3:

Main

concepts

modelling

FRC

with

DIANAMain

advantages

of

FRC

precast

tunnelsegments

Enhanced

toughness

Smallercrackopening

crackpatternmoredistributed

(durability)

Higherresistancetoimpactloadingand

improvefatigueresistance25/50Part

4:

Numerical

simulations

of

TBM

thrust

phaseMain

advantages

of

FRC

precast

tunnelsegments

No

detachment

of

crackedconcreteblocksin

tunnels

Fibresrepresenta

reinforcement

spread

out

everywhereinto

thelining(includingconcretecover)

The

presence

offiberreinforcementin

theconcretematrixwouldallow

timereductionin

fabrication,handlingandplacingofthecurvedrebars

Fibrereinforcement

cansubstitutereinforcementalongthetunnel(secondary

reinforcement)thatmay

be

usedforstressredistribution26/50Part

4:

Numerical

simulations

of

TBM

thrust

phaseMain

advantages

of

FRC

precast

tunnelsegments

Improvedindustrialprocess

No

more

storage

areasforreinforcement27/50Part

4:

Numerical

simulations

of

TBM

thrust

phaseFRC

precast

tunnel

segments

Opportunitiesoffer

by

FRC

asa

reinforcementforFRCprecast

tunnelsegmentsNon

Linear

NumericalSimulationsdeveloped

by

means

of

DIANA

Study

of

the

global

and

local

tunnelliningbehaviour28/50Part

4:

Numerical

simulations

of

TBM

thrust

phaseThrust

Phase

–

Introduction

The

precast

assembledringshould

guaranteethenecessary

longitudinalsupportforexcavation

processmadewithTBMShieldSegmentsringExcavingdirectionHydraulicJacksCutterHead

Differentapplicationmethods

ofthehydraulic

jacks

accordingto

differenttypical

configurations:

french,

japanese,

etc.29/50Part

4:

Numerical

simulations

of

TBM

thrust

phaseBarcelona

Metro

–

Line

930/50Part

4:

Numerical

simulations

of

TBM

thrust

phaseGeometrical

characteristicThickness

ofthe

ring

s=350

mmDepth

oftheringd=1800

mm7

segments+

1

key

segmentUniversal

tapered

segmentsLine

9,

double

deckconfiguration31/50Part

4:

Numerical

simulations

of

TBM

thrust

phaseDamaged

segments

during

TBM

operationsBarcelona

Metro

Line

9

During

theconstruction

oftheBarcelona

Metro

Line

9,spallinglocalizedcracks

appear:probably

due

eccentricload(relativepositionbetweenjacksand

tunnelsegment)NicolaDellaValle,2005

Bending

cracks

appear:

probably

dueto

no-smooth

supportin

thering

jointNicolaDellaValle,200532/50Part

4:

Numerical

simulations

of

TBM

thrust

phaseMaterials

adopted

Strength

class

ofthecementitious

matrix

ofallspecimens:

C50/60

Mechanical

properties

of

concrete:Constitutivelawforconcreteundercompression:-Ec=37000MPa-

fct=4.10MPa-

fc,cube=64.1MPa706050403020100EuroCode2ThorenfeldtParabola

Thefollowing

type

offiberhas

been

adopted:00,0005

0,001

0,0015

0,002

0,0025

0,003

0,0035

0,004

0,0045

0,005CompressivestrainShapehooked1100SteelFiberUltimate

tensile

strength[MPa]DosageModulus

of

elasticity

[MPa]Cross

SectionLength

[mm]Diameter

[mm]Aspect

Ratio210000circular500,756725/35/45kg/m³33/50Part

4:

Numerical

simulations

of

TBM

thrust

phaseDetermination

of

fracture

laws

4PointBendingTestson

notched

beams,

UNI

11039Determinationoffracturebilinearlaws,inverseanalysismethod.Numericalsimulationsof4PBTMesh2DPlanestress,DiscreteFractureWirand

FF1

-

45

-

C50/60

-

Vf=0,57%8,07,06,05,04,03,02,01,00,0fcts1Gffctw1wcwExperimentalFEADIANASmeareds1Gf0,00,10,20,3w1wwcCTODm

[mm]34/50Part

4:

Numerical

simulations

of

TBM

thrust

phaseNumerical

model

adopted

Normalloading

condition:idealpositioningofhydraulicjacks

and

bearingpads:Springelements,SP1TR,no-tension,positionedonthe4bearingpadsurfaces.SupportoftheringjointuniformTwopairsofactuatorsactingonsteelplates:totalserviceloadapproximately12MNSpringelements,no-tension,actingintangentialdirectioninordertosimulatethepresenceofadjacentsegments35/50Part

4:

Numerical

simulations

of

TBM

thrust

phaseLinea

9

–

Barcelona

–

Thrust

jack

phase

Thefollowingreinforcement

combinations

were

adopted:2chords350mm350mm50/1,0-Vf=0,57%45kg/m350/0,75-Vf=0,32%25kg/m3Stiirups6@200mm14=0,22%RCO+50/0,75-Vf=0,32%71kg/m3RC97kg/m3RC+50/0,75-Vf=0,32%122kg/m336/50Part

4:

Numerical

simulations

of

TBM

thrust

phaseLinea

9

–

Barcelona

–

Numerical

results

Normal

loadingcondition(ideal

placement

of

supports

andjacks):Normal

loading

condition353025201510532,521,5150/1,0

-

Vf=0,57%50/0,75-

Vf=0,32%RCRC+

50/0,75-

Vf=0,32%RCO

+

50/0,75

-

Vf=0,32%0,5000,000,501,001,502,002,503,00Splitting

cracksAverage

displacement

under

the

loading

surfaces

[mm]Spalling

cracks37/50Part

4:

Numerical

simulations

of

TBM

thrust

phaseLinea

9

–

Barcelona

–

Numerical

resultsNormal

loading

condition35302520151053radial2,5z,

longitudinal

tunnel

axis2Point

3Point

2Point

1115mm50/1,0-

Vf=0,57%

-

Point150/0,75-

Vf=0,32%

-

Point1RC-

Point11,51tangentialRC+

50/0,75-

Vf=0,32%

-

Point1RCO+

50/0,75-

Vf=0,32%

-

Point10,50→

Schemeofthepointsofthemeasurementusedfor00,000,200,400,600,801,001,20

studyingthesplittingphenomenaunderthethrustRelative

displacement

inradial

direction

under

the

thrust

jacks

[mm]Normal

loading

conditionjacks.353025201510532,52900

mm50/1,0-

Vf=0,57%50/0,75-Vf=0,32%RC1,5→

Schemeofthebaseofmeasurementadoptedforestimatingthewidthofspalling

cracks;1RC+

50/0,75-

Vf=0,32%RCO+

50/0,75-Vf=0,32%0,5000,000,501,001,502,002,50Relative

displacement

in

the

region

between

the

thrust

jacks

[mm]Part

4:

Numerical

simulations

of

TBM

thrust

phaseLinea

9

–

Barcelona

–

Numerical

results→

Lineofinvestigationsadoptedundertheloadingareasofthethrustjacks:→

Interpretationofthelocalbehaviourundertheloadingareas:are-distributiontakeplaceinanareaofabout550mmwhichcorrespondstoabout1,6timesthethicknessoftheliningNormal

loading

condition

-

Line

01Normal

loading

condition

-

Line

015,00,010,05,00200400600800100012001400160018000,0020040060080010001200140016001800-5,0dh=350mm-5,0d550-600mm-10,0-15,0-20,02,21S.Load2,58S.Load2,64S.Load-10,0-15,0-20,01,96S.Load2,09S.LoadDistance

[mm]Distance

[mm]39/50Part

4:

Numerical

simulations

of

TBM

thrust

phaseCheck

of

mesh

refinementMeshrefinement(Coarse

mesh)FIRST

CRACK(Refined

mesh)FIRST

CRACKSERVICE

LOAD1,5*SERVICE

LOAD2*SERVICE

LOADSERVICE

LOAD1,5*SERVICE

LOAD2*SERVICE

LOAD40/50Part

4:

Numerical

simulations

of

TBM

thrust

phaseIrregularities

A

number

of

irregularities

can

occurin

practice

during

the

thrust

jack

phase1)

thrust

jacks

may

be

not

exactly

on

place2)ringjointmay

not

be

plane1)

thrust

jacks

may

be

not

exactly

on

place:Inside

tunnel-

Eccentricityofthehydraulicjacks-

InclinationofthehydraulicjacksEccentricityOutside

tunnelInside

tunnelInclinationOutside

tunnel41/50Part

4:

Numerical

simulations

of

TBM

thrust

phaseIrregularitiesOutwardeccentricityInwardeccentricity42/50Part

4:

Numerical

simulations

of

TBM

thrust

phaseInfluence

of

irregularities2)ring

jointmay

not

be

in

plane:Normalloadingcondition;segmentperfectlyplacedNon-smoothsupportsintheringjointCombinationoftheFrenchandJapanesejackconfiguration

Numericalresults

of

aneccentric

load

are

presented

hereinincomparisonwithnormalloadingcondition43/50Part

4:

Numerical

simulations

of

TBM

thrust

phaseEccentric

placement

of

thrust

jack

Eccentricplacement

of

thrustjackin

radialdirection:willincrease

thespallingstresses

and

can

damagethesegment-EccentricplacementhasbeenmodeledinFEanalysisasatriangularpressuredistributionontheloadingsurface-Consequently,aneccentricityof37.3mmhasbeenappliedInsidetunnelInsidetunnelOutside

tunnelOutside

tunnel44/50Part

4:

Numerical

simulations

of

TBM

thrust

phaseEccentric

placement

of

thrust

jack

Eccentricityappliedoutward:Becauseoftheeccentricity,thesegmenttiltsoutwardprovidingano-smoothsupportAbendingmomentoccursSplitting

andspallingstressesinitiate

at

an

earlierloadlevel.45/50Part

4:

Numerical

simulations

of

TBM

thrust

phaseEccentric

placement

of

thrust

jack

Eccentricity

appliedoutward:Eccentricityoutside302520151052,52Normal

l.condition-Fiberreinforcementcannotlocallycompetewithtraditionalrebarsconcentratedinthechords(proposedsolution)1,5150/1,0-Vf=0,57%50/0,75-Vf=0,32%RCEccentricityoutside2520,5RC+50/0,75-Vf=0,32%RCO+50/0,75-Vf=0,32%2015001,50,000,501,001,502,002,503,00Average

displacement

under

the

load

surfaces

[mm]-

Reductionofthes.f.withrespecttothe1normalloadcond.;1050/1,0-Vf=0,57%50/0,75-Vf=0,32%-NoticeableincrementofthecrackpatternBetweentheloadingareas(thrustjacks);0,550RCRC+50/0,75-Vf=0,32%RCO+

50/1,0-Vf=0,32%06,00-1,000,001,002,003,004,005,00Relative

displacement

in

the

region

between

the

thr