Variability Characteristics of Structural Health Variability Characteristics of Structural Health Monitoring Data and Monitoring Data and Development of Engineering Report ToolDevelopment of Engineering Report Tool
Nicolás A. LondoñoNicolás A. Londoño
David T. LauDavid T. Lau
Department of Civil & Environmental EngineeringDepartment of Civil & Environmental Engineering
Carleton UniversityCarleton University
Ottawa, CanadaOttawa, Canada
SAMCO Summer AcademyZell am See, Austria
Sept 5-9, 2005
OverviewOverview
► IntroductionIntroduction► Computer ToolsComputer Tools► Research using Confederation Research using Confederation
Bridge field monitoring dataBridge field monitoring data1.1. Design properties verificationDesign properties verification
2.2. Variability of monitoring dataVariability of monitoring data
► Engineering Report ToolEngineering Report Tool► ConclusionsConclusions
Confederation BridgeConfederation Bridge
Monitoring SystemMonitoring System
Sensors
Data logger
On Site Computers
Carleton University
Processing
Internet
Analysis (System Identification)• Frequency
• Mode-shape
• Damping ratios
Condition Assessment
Engineering Reporting and Interpretation
LAN
Wind scenario Traffic scenario
40
seconds
600
seconds
Data characteristicsData characteristics
Wind scenarios
Traffic scenarios
Stochastic Subspace IdentificationStochastic Subspace Identification
Data cross-correlations
TN
k
refkik
refi N
1
1ˆ yyR
Output-only monitoring data Nkk ,...,1, y
Block Toeplitz Matrix
refi
refi
refi
refrefi
refi
refrefi
refi
refi
RRR
RRR
RRR
T
ˆ...ˆˆ............
ˆ...ˆˆ
ˆ...ˆˆ
ˆ
2212
21
11
|1
refii
refrefrefi
i
refi ΓOGAGGA
CA
CA
C
T
......
1
1
|1
GCAR 1 ii
Singular Value Decomposition T
T
TTref
i 111
2
1121|1 VSU
V
V
00
0SUUUSVT
21
11SUO iTref
i 121
1 VSΓ
Stochastic State-Space Model Matrices
:),:1(:)),1(:1( lilil ii OOA
:,:1 liOC
FrequenciesMode Shapes
Damping Ratios
1ΨΛΨACΨV
kkk
kkk
vCxy
wAxx
1State Space
model
SPPLASH – Signal Processing PLatform for Analysis of Structural Health
Identified 2.76 HzIdentified 2.76 Hz
Theoretical 2.59 HzTheoretical 2.59 Hz
MAC 0.89MAC 0.89
Verification StudyVerification Study – Modal Frequencies –– Modal Frequencies –
Mod
e N
um
ber
Mod
e N
um
ber
Typ
eTyp
e
EXPERIMENTAL FREQUENCYEXPERIMENTAL FREQUENCY Experimental – Theoretical Experimental – Theoretical Frequency DifferenceFrequency Difference
MeanMean(Hz)(Hz)
MinMin (Hz)(Hz)
MaxMax (Hz)(Hz)
Range ofRange ofVariability Variability
(%)(%)
StdStd (% of (% of mean)mean)
Beam Beam E35E35 (%)(%)
Beam Beam E43E43 (%)(%)
Shell Shell E35E35 (%)(%)
Shell E43Shell E43 (%)(%)
11 T T 0.340.34 0.320.32 0.370.37 1616 5.85.8 2222 1010 66 -4-422 TT 0.470.47 0.460.46 0.480.48 55 1.41.4 22 -8-8 -3-3 -12-1233 VV 0.570.57 0.520.52 0.630.63 1919 6.86.8 2121 99 1515 4444 VV 0.650.65 0.640.64 0.660.66 33 11 1212 11 33 -7-755 VV 0.680.68 0.650.65 0.710.71 99 2.12.1 1010 -1-1 -- --77 VV 0.920.92 0.890.89 0.950.95 77 22 1616 55 77 -4-488 VV 0.970.97 0.950.95 0.990.99 44 1.51.5 1818 77 -- --
1010 VV 1.621.62 1.61.6 1.661.66 44 1.31.3 -- -- -- --1111 VV 1.811.81 1.781.78 1.861.86 55 1.21.2 1313 22 1010 -1-11212 VV 2.732.73 2.702.70 2.792.79 33 0.90.9 1717 55 -- --1313 VV 2.832.83 2.762.76 2.912.91 55 2.02.0 1515 44 77 -3-31414 VV 2.882.88 2.832.83 2.942.94 44 1.71.7 -- -- -- --1616 TP31-ToTP31-To 3.303.30 3.263.26 3.343.34 33 1.01.0 -- -- 44 -6-61818 VV 3.43.4 3.293.29 3.473.47 55 1.51.5 -- -- -- --1919 V-LV-L 3.793.79 3.713.71 3.923.92 55 1.81.8 2323 1111 1010 552323 4.714.71 4.664.66 4.744.74 22 0.60.6 -- -- -- --2525 VV 5.135.13 5.035.03 5.205.20 33 1.31.3 1616 55 -- --AveragesAverages -- -- -- 4.84.8 1.81.8 1515 44 77 -3-3
Verification StudyVerification Study – Modal Damping and MAC – Modal Damping and MAC ––
Mod
e N
um
ber
Mod
e N
um
ber
Fre
qu
en
cy
Fre
qu
en
cy
MODAL DAMPING MODAL DAMPING RATIOS (RATIOS ())
MODAL ASSURANCE MODAL ASSURANCE CRITERIONCRITERION (MAC)(MAC)
Mean Mean (%)(%)
Standard Standard Deviation Deviation
(% of mean)(% of mean)
ExperimentExperimentalal
ExperimentaExperimental vs.l vs.
FE (shell)FE (shell)
11 0.340.34 1.91.9 6666 0.940.94 0.890.8922 0.470.47 1.71.7 3939 0.900.90 0.850.8533 0.570.57 3.83.8 3737 0.820.82 0.870.8744 0.650.65 1.41.4 7373 0.890.89 0.970.9755 0.680.68 2.12.1 3737 0.850.85 --77 0.920.92 1.51.5 4242 0.910.91 0.980.9888 0.970.97 1.61.6 4242 0.920.92 --
1010 1.621.62 1.61.6 7070 0.930.93 --1111 1.811.81 1.51.5 5353 0.940.94 0.960.961212 2.732.73 0.80.8 5252 0.910.91 --1313 2.832.83 1.31.3 5757 0.920.92 0.890.891414 2.882.88 1.01.0 5959 0.890.89 --1616 3.303.30 0.60.6 4848 0.560.56 0.730.731818 3.43.4 0.80.8 5050 0.900.90 --1919 3.793.79 0.90.9 5757 0.910.91 0.580.582323 4.714.71 0.80.8 4242 0.850.85 --2525 5.135.13 0.80.8 4848 0.860.86 --
AverageAveragess
-- 1.31.3 5454 0.880.88 0.790.79
VariabilityVariability-Sources--Sources-
►Numerical uncertaintiesNumerical uncertainties Deviation from model assumptionsDeviation from model assumptions
►Data non-stationarityData non-stationarity►Non-whiteness of the inputsNon-whiteness of the inputs
Measurement noiseMeasurement noise Computational uncertaintiesComputational uncertainties
►Use of finite datasetsUse of finite datasets►Analyst inputAnalyst input
► Physical UncertaintiesPhysical Uncertainties Environmental and loading fluctuationsEnvironmental and loading fluctuations
►Temperature effectsTemperature effects►Bridge-vehicle coupling, etc.Bridge-vehicle coupling, etc.
Baseline VariabilityBaseline Variability
Mode Mode shape shape
variabilitvariabilityy
Baseline variabilityBaseline variability
General variabilityGeneral variability
Temperature EffectTemperature Effect
Temperature (Hz)Temperature (Hz)
Mod
al Fre
qu
en
cy (
Hz)
Mod
al Fre
qu
en
cy (
Hz)
Variability vs. sensitivityVariability vs. sensitivity
Engineering Report ToolEngineering Report Tool
►MotivationMotivation Enhance feedback given to bridge owners Enhance feedback given to bridge owners
and operators and operators Provide timely systematic information of Provide timely systematic information of
engineering relevance for decision engineering relevance for decision supportsupport
►RequirementsRequirements Automated file sorting and processingAutomated file sorting and processing Easy to search database Easy to search database
ENDEND
Confederation Bridge Monitoring Confederation Bridge Monitoring DataData
► Truck Traffic induced vibrationTruck Traffic induced vibration
► Wind storm Wind storm (Nov. 7 2001)(Nov. 7 2001)
► Typical ambient vibrationTypical ambient vibration