Post on 17-Jul-2016
description
STRUCTURALHEALTHMONITORING
(SHM)
(SHM)
dr.ing.N
AGYGYÖ
RGYTamás
lecturer
2012v1
REFERENCES
•SHM
http://wwwshmlivecom/
•SHM
http://www.shmlive.com/
•SAMCO
http://www.samco.org/network/index.htm
•ISISandSAMCOEducationalModule5:AnIntroductiontoStructuralHealth
Monitoring
Monitoring
INTRODUCTION
WhyweneedSHM?
•Populationdependsonanextensiveinfrastructuresystem
roads
highways
highways
buildings
…etc
•Theinfrastructuresystemhassuffered
neglect
dti
tideterioration
lackoffunding
…
GlobalInfrastructure
Crisis
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GlobalInfrastructure
Crisis
INTRODUCTION
WhyweneedSHM?
•Factorsleadingtotheextensivedegradation
Factor1
Unsatisfactoryinspectionandmonitoringof
Factor1
Unsatisfactoryinspectionandmonitoringof
existinginfrastructure
Consequences:
Problemsbecomeapparentonlywhen
structuresareindireneedofrepair
Result
Repaircostsbecomecomparableto
replacementcosts
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INTRODUCTION
WhyweneedSHM?
•Factorsleadingtotheextensivedegradation
Factor2
Corrosionofconventionalsteel
Factor2
Corrosionofconventionalsteel
reinforcementwithinconcrete
Consequences:
Expansionofsteelleadstocrackingand
spalling,furtherdeterioration
Result
Reductionsin
strength
andserviceability,
resultingin
needforrepairand/orreplacement
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INTRODUCTION
WhyweneedSHM?
•Factorsleadingtotheextensivedegradation
Factor3
Increasedloadsordesignrequirementsover
Factor3
Increasedloadsordesignrequirementsover
time(e.g.heaviertrucks)
Consequences:
Increaseddeteriorationduetooverloadsor
tostructuralinadequaciesresultingfromdesign
Result
Structuresdeemedunsafe
orunserviceable
andstrengtheningorreplacementisrequired
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INTRODUCTION
WhyweneedSHM?
•Factorsleadingtotheextensivedegradation
Factor4
Overalldeteriorationand/oraging
Factor4
Overalldeteriorationand/oraging
Consequences:
Variousdetrimentaleffectsonstructural
performance,bothsafetyandserviceability
Result
Needforrepair,rehabilitation,
strengtheningorreplacement
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INTRODUCTION
Materials&Technologies
SHM
FRP
++
Newandinnovative
materialsandmonitoringtoolsthatprolong
theservicelivesofstructureswhiledecreasingcosts
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WHATISSHM?
Assessingtheinserviceperform
anceofstructuresusingavariety
ofmeasurementtechniques
Leadingto“smart”structures
EXTERNAL
DISTURBANCES
STRUCTURE
RESPONSE
SENSORS
ACTUATORS
CONTROLLER
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WHATISSHM?
Inspection
Onsitenondestructiveexaminationtoestablish
thepresentconditionofthestructure
p
Loadtesting
Testofthestructureorpartthereofbyloadingto
ealateitsbehaiororpropertiesortopredictits
evaluateitsbehaviororproperties,ortopredictits
loadbearingcapacity
Monitoring
Frequentorcontinuous,normallylongterm,
observationormeasurementofstructuralconditionsor
actions
Bjö
rnT
äljs
ten
WHATISSHM?
Whymonitoring?
followupphysicalphenomenon
checkuotthecalculationmodels
Bjö
rnT
äljs
ten
checkuotthecalculationmodels
assessmentofstructures
verificationofthestrengtheningeffects
WHATISSHM?
WhatisSHM
becomingpopular?
Emerginguse
ofSHM
isaresultof:
1.Theincreasingneedfor
Monitoringofinnovativedesignsandmaterials
Bettermanagementofexistingstructures
Bettermanagementofexistingstructures
2.Theongoingdevelopmentof
N(
Fib
OtiS
(FOS)“
t”Newsensors(e.g.FiberOpticSensors(FOS),“smart”
materialsetc.)
Dataacquisitionsystems(DAS)
Wirelessandinternettechnologies
Datatransmission,collection,archivingandretrievalsystems
Dataprocessingandeventidentification
Dataprocessingandeventidentification
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WHATISSHM?
BodyAnalogy
dl
MedicalDoctor
SHM
Engineer
•Monitorpatient’shealth
•Usesmedicalequipment
•Monitorconditionofstructures
•Usessensorsto
check
overall
•Usesmedicalequipment
tocheck
overallhealth
•Prescribescorrective
dii
ifi
d
•Usessensorsto
check
overall
structuralhealth
•Ifexcessivestress
or
df
titit
timedicineifrequired
deform
ation,correctsituation
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WHATISSHM?
System
Components
AcquisitionofData
CommunicationofData
IntelligentProcessing
IntelligentProcessing
http://www.smartstructuresinc.com
StorageofProcessedData
RetrievalofData
Diagnostics
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WHATISSHM?
SHM
Categories
StaticField
Testing:
Behaviourtests
DynamicField
Testing:
Stresshistorytests
Behaviourtests
Diagnostictests
Prooftests
yAmbientvibrationtests
Dyn.LoadAllowance(DLA)tests
Pullback(anchoredcables)tests
Pullback(anchoredcables)tests
PeriodicMonitoring:
Fieldtesting
ContinuousMonitoring:
Activemonitoring
Fieldtesting
Teststodetermine
changesinstructure
Activemonitoring
Passivemonitoring
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WHATISSHM?
ClassificationofSHM
Systems
LevelIV
Detectpresence
locationseverityandconsequencesofdamage
Detectpresence,location,severityandconsequencesofdamage
LevelIII
LevelIII
Detectpresence,locationandseverityofdamage
lLevelII
Detectpresenceandlocationofdamage
LevelI
Detectpresenceofdamage
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Detectpresenceofdamage
WHATISSHM?
ClassificationofSHM
Systems
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WHATISSHM?
AdvantagesofSHM
AdvantagesofSHM
Increasedunderstandingofinsitustructuralbehaviour
g
Earlydamagedetection
Assurancesofstructuralstrengthandserviceability
Assurancesofstructuralstrengthandserviceability
Decreaseddowntimeforinspectionandrepair
/Developmentofrationalmaintenance/managementstrategies
Increasedeffectivenessinallocationofscarceresources
Enablesandencouragesuseofnewandinnovativematerials
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METHODOLO
GY
•IdealSHMsystem:
1.Informationondemandaboutastructure’shealth
2.Warningsregardinganydamagedetected
•DevelopmentofaSHMsysteminvolvesutilizing
informationfrommanydifferentengineeringdisciplines
informationfrommanydifferentengineeringdisciplines
Computers
Materials
Ci
iCommunication
Structures
Sensors
DamageDetection
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DamageDetection
IntelligentProcessing
DataCollection
METHODOLO
GY
System
Components
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METHODOLO
GY
Monitoringprinciples
BasicMonitoringMethodology
BasicMonitoringMethodology
Competenceofthe
bid
i
Monitoring
objectives
bridgeengineer
What?
Where?
Bridgemodel
Constraints
Where?
When?
Designmodel
monitoringsystem
How?
Designofphysical
monitoringsystem
Installationofphysicalmonitoring
system
Competenceofthe
monitoringengineer
system
Validationofmodelandphysical
monitoringsystem
Aft
er
Gla
uco
Feltrin, E
MP
A,
2007
Maintenanceofmodelandphysical
monitoringsystem
METHODOLO
GY
Monitoringprinciples
MonitoringPrinciples
0
0.05
m]
MonitoringPrinciples
01
23
45
6-0
.1
-0.0
5
d [mm
Dis
pla
cem
ent
D1
0
0.05
mm]
Interactionbridge
01
23
45
6-0
.1
-0.0
5
d [m
Dis
pla
cem
ent
D2
time
[s]
Domodelresultsmatch
Improved
lti
model/monitoring
withmonitoringresults?
correlation
Mdifiti
fdl
Bjö
rnT
äljs
ten
Modificationofmodel
METHODOLO
GY
Monitoringprinciples
Monitoring
Monitoring
Verificationbymonitoring–notnew
TestingofasteeltrussinEnglandforarailwaybridgeinIndiainthe19thcentury
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METHODOLO
GY
1–AcquisitionofData
Thecollectionofrawdata:strains,deformations,
accelerations,temperatures,moisturelevels,acoustic
ii
dld
emissionsandloads
(a)SelectionofSensors
() Appropriateandrobustsensors
Longtermversusshorttermmonitoring
Longtermversusshorttermmonitoring
Whataspectsofthestructurewillbemonitored?
Sensorsmustserveintendedfunctionforrequiredduration
Sensorsmustserveintendedfunctionforrequiredduration
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METHODOLO
GY
1–AcquisitionofData
(b)SensorInstallationandPlacement
Mustbeabletoinstallsensorswithoutalteringthebehaviourof
g
thestructure
Featuressuchassensorwiringconduitjunctionboxesandother
Featuressuchassensorwiring,conduit,junctionboxesandother
accessoriesmustbeaccountedforintheinitialstructuraldesign
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METHODOLO
GY
1–AcquisitionofData
(c)Transferto
Data
AcquisitionSystem
(DAS)
•Method1
Leadwire
directphysicallinkbetweensensorandDAS
leastexpensiveandmostcommon
leastexpensiveandmostcommon
notpracticalforsomelargestructures
longleadwiresincreasesignal“noise”
•Method
Wireless
transm
ission
Moreexpensive
Moreexpensive
Signalsaretransferredmoreslowlyandarelesssecure
Useisexpectedtoincreaseinthefuture
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METHODOLO
GY
1–AcquisitionofData
(d)Data
SamplingandCollection
GeneralRule:
Theamountofdatashouldnotbesoscantyasto
jeopardize
itsusefulnessnorshoulditbesovoluminousasto
itsusefulness,norshoulditbesovoluminousasto
overwhelminterpretation
Issues:Numberofsensorsanddatasamplingrates
Datasortingforonsitestorage
Datasortingforonsitestorage
Insomecases,largevolumesofdata
Rlt
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Result: Efficientstrategiesneededfordatasamplingandstoring
METHODOLO
GY
1–AcquisitionofData
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METHODOLO
GY
1–AcquisitionofData
Whatismonitored,howandwhy?
Ld
Load
Magnitudeandconfigurationofforcesappliedtoa
structure
structureAretheyasexpected?
Howaretheydistributed?
Measuredusingloadcellsorinferredusingstraindata
Measuredusingloadcellsorinferredusingstraindata
Deform
ation
Excessiveorunexpecteddeformation,mayresultinaneed
forrehabilitationorupgrade
Aretheyasexpected?
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Aretheyasexpected?
Measuredusingvarioustransducers
METHODOLO
GY
1–AcquisitionofData
Strain
Intensityofdeformation
Magnitudeandvariationofstrainscanbeexaminedto
evaluatesafetyandintegrity
Measuredusingstraingauges
gg
gFOS,electrical,vibratingwire,etc.
Tt
Temperature
Changesintemperaturecausedeformation
ThermalExpansion
pRepeatedcyclescancausedamage
Temperatureaffectsstrainreadings
Tempmustbe“removed”fromstraindata
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Tempmustberemovedfromstraindata
MeasuredusingThermocouples(TC),Temperature
IndicatorControllers(TIC),thermistors
METHODOLO
GY
1–AcquisitionofData
Acceleration
Loadscauseaccelerationsofstructuralcomponentsand
viceversa Howisthestructureresistingaccelerationsandthe
resultingloads?
gWidespreaduseinhighlyseismicregions
Measuredusingaccelerometers
WindSpeedandPressure
Windloadscangovernthedesignoflongspanbridgesand
gg
gp
gtallbuildings
Recordspeedandpressureatvariouslocations
Measuredusinganemometers
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Measuredusinganemometers
METHODOLO
GY
1–AcquisitionofData
AcousticEmissions
Whencertainstructuralelementsbreak,theyemitnoise
lf
hd
lAElistensforthenoises,andpinpointslocations
usingtriangulation
Usedinposttensionedconcreteandcablestayed
py
structures
Measuredusingmicrophones
VideoMonitoring
Timestampedvideosandpicturescanbeusedtowitness
pp
extremeloadsorevents
Datacanbecorrelatedwithimages
Permitsfindingofoverloadedtrucks IS
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Permitsfindingofoverloadedtrucks
Emerginginternetcameratechnologyisused
METHODOLO
GY
2–CommunicationofData
•ReferstodatatransferfromtheDAStoanoffsitelocation
•Allowsforremotemonitoring,eliminationofsitevisits
Telephone
lines
DAS
Internet
Offsite
Location
Wireless
technologies
Location
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technologies
METHODOLO
GY
3–IntelligentProcessingofData
•Requiredbeforedatacanbestoredforlaterinterpretation
andanalysis
•Thegoalistoremovemundanedata,noise,thermal,or
otherunwantedeffectsandtomakedatainterpretation:
otherunwantedeffectsandtomakedatainterpretation:
Easier
Faster
Moreaccurate
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METHODOLO
GY
4–StorageofProcessedData
•Datamaybestoredforverylongperiodsoftime
Retrieveddatamustbeunderstandable
Datamustnotbecorrupted
Sufficientmemorymustbeavailable
•Datafilesmustbewelldocumentedforfuture
interpretation
interpretation
•Itiscommontodisregardrawdataandstoreonly
processedoranalyzeddata
Thisdoesnotallowforreinterpretation
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METHODOLO
GY
5–Diagnostics
•Extremelyimportantcomponent
Convertsabstractdatasignalsintouseful
informationaboutstructuralresponseandcondition
•No“standard”rulesexistfordiagnostics
•Nostandardrulesexistfordiagnostics
•Methodologyuseddependson
Methodologyuseddependson
Typeofstructure
Typeandlocationofsensorsused
Motivationformonitoring
Structuralresponsesunderconsideration
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METHODOLO
GY
6–Data
Retrieval
•Whenstoringdataforretrieval,consider
1.Significanceofdata
2.Confidenceinanalysis
Rem
ember:
ThegoalofSH
Misto
providedetailedphysicaldata
which
ThegoalofSH
Misto
providedetailedphysicaldata
which
canbeusedto
enablerational,knowledgebased
engineeringdecisions.
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SENSORTECHNOLO
GY
•Manysensortypesarecurrentlyavailable
ChoiceforSHMdependsonvariousfactors
•Fibreopticsensors(FOSs)
Newerclassofsensors
Newerclassofsensors
Emergingforinfrastructureapplications
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SENSORTECHNOLO
GY
FOS
FOSAdvantages:
Stability
Increasedlongtermstabilityanddecreased
noise
Nonconductive
Immunetoelectromagneticandradio
frequencyinterference
frequencyinterference
Flexibility
MultiplexingandDistributedsensing
Convenience
Light,smalldiameters,noncorrosive,
bddbl
ilb
dbl
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embeddable,easilybondable
SENSORTECHNOLO
GY
HowdoFOSswork?
Sensingusingopticalfibresandtechniques
hb
(l)
dlfb
dd
Lightbeam
(laser)issentdownanopticalfibretowardagauged
length
Lightwavesmeasurechangesinstate(i.e.elongationorcontraction)
gg
(g
)Changeinreflectedlightwavesiscorrelatedtostrainreading
Demodulationunitcalculatesstrainfromlightsignalsandgives
voltage
voltage
DASconvertsvoltagetostraindataforprocessing
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SENSORTECHNOLO
GY
SensorTechnology
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SENSORTECHNOLO
GY
SensorTechnology
Characteristics:
fdd
Useforstaticanddynamicmonitoring
Embeddable,bondableandweldable
Gaugelengthcanvaryfromcm
tomorethan1km
gg
yThermalandmechanicalstrainscanbeseparated
Usefultomeasure:
Usefultomeasure:
Widthofcracks
Straintransferinbondedjoints
Si
Stressconcentrations
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SHM
SYSTEM
DESIGN
1.DesignIssues
DefinitionofSHMobjectives
Typesofmonitoring
Sensorplacement
p
DurabilityandlifespanofSHM
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SHM
SYSTEM
DESIGN
2.InstallationIssues
Contractoreducation
Sensoridentification
Sensordamageduring
construction
Structuralchangesinducedby
fpresenceofSHMsystem
Pi
i
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Protectionagainst
deteriorationandvandalism
SHM
SYSTEM
DESIGN
3.Use
Issues
Disseminationof
performanceresults
Continuityofknowledge
yg
lld
Datacollectionand
management
Publicawareness
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SHM
SYSTEM
DESIGN
Methodology
dfhd
dh
1.Identifythedamageordeteriorationmechanisms
2Categorizeinfluenceofdeteriorationonthemechanical
2.Categorizeinfluenceofdeteriorationonthemechanical
response Theoreticalandnumericalmodelsofstructure
3.Establishcharacteristicresponseofkeyparameters
Etblih
itiit
fht
itl
lf
Establishsensitivityofeachtoanappropriatelevelof
deterioration
4.Selecttheparametersanddefineperformanceindex
Relateschangesinresponsetolevelofdeterioration
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SHM
SYSTEM
DESIGN
Methodology
5.Designsystem
Selectionofsensors,dataacquisitionandmanagement
Datainterpretation
Datainterpretation
6.InstallandcalibrateSHMsystem(baselinereadings)
7.Assessfielddataandadaptsystemasnecessary
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THEFUTUREOFSHM l
lh
•SHMisincreasinglyseenasanimportanttoolinthe
maintenanceofsustainableinfrastructuresystems
Ongoingadvancementsareexpected,emerging
technologiesinclude:
g SmartComposites
LiveStructures
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THEFUTUREOFSHM
SmartComposites
SmartComposites
Composites(egFRP)withsensorsembeddedinsidethat
Composites(e.g.FRP)withsensorsembeddedinsidethat
provideinformationabouttheconditionofthestructural
component
p
Muscle/M
emberAnalogy:
Muscleshavenervecells
embeddedinthemthatprovide
informationtothebrainabout
Smartcompositeshavesensors
insidethatprovideinformation
aboutthestructuralmembers’
informationtothebrainabout
theconditionsofthemuscles
aboutthestructuralmembers
condition
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THEFUTUREOFSHM
SmartComposites
LiveStructures
•Representthecuttingedgeofcivilengineeringdesignand
•Representthecuttingedgeofcivilengineeringdesignand
analysis
•Livestructuresarecapableof:
Sensingloads,deformations,anddamage
Correctingandcounteringtheloadeffects
•Presentlystructuresarelargelytheoretical
•Presentlystructuresarelargelytheoretical
•Accomplishedusingemergingselfactuatingmaterials
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pg
gg
g
SUMMARYANDCONCLU
SION
llh
StructuralHealthMonitoring
Providesthecivilengineeringcommunitywithasuiteof
Providesthecivilengineeringcommunitywithasuiteof
optionsformonitoring,analysingandunderstandingthe
healthofourinfrastructures ystems
y
Provideessentialtoolstoengineerswhomusttakesteps
toim
provethesustainabilityofinfrastructuresystems
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SUMMARYANDCONCLU
SION
CaseStudy
TheÖrnsköldsviksbridge
2006
Step1
Enhancedassessment
Assessmentprocedureforthebridge
CaseStudy–TheÖrnsköldsviksbridge
2006
Step1
Initialassessment
•Sitevisits
several
Enhancedassessment
•Laboratoryinvestigations
•InvestigationsofLoadModels
•Reliabilitybasedinvestigations
Step3
•Studyofdocuments
•Studyandcarriedout
simplecalculations
•Reliabilitybasedinvestigations
•Strengtheningcalculations
•Monitoring
•Refinedcalculations,FEmodels
•Decisionanalysis
•Decisionanalysis
Intermediateassessment
•Furtherinspections
•Materialtestingcoresetc
Destructivetesting
Step2
Materialtesting,coresetc
•Detailedcalculations
•Investigationsofloadingetc
•Planningfortestingetc
•SimpleFEModels
•DesignModels
•UltimateLimitState
•Verification
Dild
li
Bjö
rnT
äljs
ten
Step4
SimpleFEModels.
•Detailedanalysis
•NonlinearFEModels
SUMMARYANDCONCLU
SION
CaseStudy–TheÖrnsköldsviksbridge
2006
yg
StructuralAssessment
S1:Survey
S1:Questionnaire
Bridgeowner/Consultant
Bridgeowner/consultant
S2:Conditionassessment
VisualInspections
S2:SimpleFE
Consultant
S2:Nondestructivetests
VisualInspections
Radar,ultrasonictestsetc.
S2:Materialsamples
Radar,ultrasonictestsetc.
S3:Laboratorytesting B
jörn
Täljs
ten
Drillingofcores,pulloffetc.
Concrete,Steeletc.
SUMMARYANDCONCLU
SION
CaseStudy–TheÖrnsköldsviksbridge
2006
yg
StructuralAssessment
S3:Sensorinstallation
Specialistconsultant
120
130
Slab
26
Ftg
A1 Ö
30
Ftg
A5 V
120
130
Slab
26
Ftg
A1 Ö
30
Ftg
A5 V
S4:Loadtest1
Testinginstitutes
0
10
20
30
40
50
60
70
80
90
100
110
0500
1000
1500
2000
2500
3000
3500
4000
Tim
e Ö
vik2
(P
latt
a 1
U1.b
in)
0
10
20
30
40
50
60
70
80
90
100
110
0500
1000
1500
2000
2500
3000
3500
4000
Tim
e Ö
vik2
(P
latt
a 1
U1.b
in)
S4:Strengthening
Specialistcontractors
S4:Loadtest2
Testinginstitutes
S4:Detailedevaluation
Bjö
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äljs
ten
SUMMARYANDCONCLU
SION
CaseStudy–TheÖrnsköldsviksbridge
2006
yg
PredictedLoadCarryingCapacity
Bjö
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SUMMARYANDCONCLU
SION
CaseStudy–TheÖrnsköldsviksbridge
2006
yg
PredictedLoadCarryingCapacity
•Eurocode2,
=30o
P=6,1MN
•Eurocode2,
=22o
P=8,8MN
Eurocode2,
22
P8,8MN
•MCFT,Response,
30o
P=8,7MN
•2DNonlinearAtena
30o
P=108MN
•2DNonlinear,Atena,
30
P=10,8MN
•Test,
30o
P=11,7MN
Bjö
rnT
äljs
ten
SUMMARYANDCONCLU
SION
Periodiclongtimemonitoring
CaseStudy–Kallkällan1998
80.0
0
Strains
40.0
0
60.0
0
rain [e-6]
Stas
20.0
0
St
0.0
0
Tim
eB
efo
re s
treng
then
ing
After
stre
ngth
enin
g"L
ong-t
erm
" behavi
or
Measurementofstrains
Bjö
rnT
äljs
ten
END
END
Ofthe
Ofthe
1stversion
1version