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ANALYSIS AND MITIGATION OF RISKS IN INFRASTRUCTURES | INFRARISK-July 19
Hugo Guimarães
Risk analysis of bridges using a new reliability-based robustness assessment methodology
2Hugo Guimarães / Risk analysis of bridges using a new reliability-based robustness assessment methodology
Agenda
Risk-informed decision making• Motivation and Research Goal
• Metamodeling-based methods for reliability analysis
• Framework for robustness assessment
• Case studies
• Additional Contributions
• Conclusions and Future Developments
3Hugo Guimarães / Risk analysis of bridges using a new reliability-based robustness assessment methodology
Bridge Management Systems
Risk-informed decision making
Transportation Network
Chackkebges
EfficientManagement
DecayProcess
LimitedResources
PublicExpectations
PublicDemands
…Challenges for Owners
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Bridge Management Systems
Performanceindicator
NDTTesting
VisualInspection
Monitoringsystem
Conditionrating
…Component Level
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Recent Events
… More than 40 bridge failures were reported since 2014!!!
… Majority of them was made by concrete
… Main reasons were:• Faulty design or construction error• Loss of Key elements by:
• Collision• Landslide• Scour
• Poor Maintenance
6Hugo Guimarães / Risk analysis of bridges using a new reliability-based robustness assessment methodology
Recent bridge failures
7Hugo Guimarães / Risk analysis of bridges using a new reliability-based robustness assessment methodology
Recent bridge traffic disruptions
8Hugo Guimarães / Risk analysis of bridges using a new reliability-based robustness assessment methodology
Research Goal
Reliability Analysis
NonlinearFE Analysis
Robustness Assessment
Risk-informed decision making
The goal is to contribute new generation of risk-based bridge management systems
Transportation Network
9Hugo Guimarães / Risk analysis of bridges using a new reliability-based robustness assessment methodology
Robustness assessment methodology
Performance underextreme sudden events
Performance underservice conditions
Criticality level Risk indicatorTransportation Network
Structural Performance
… System-level performance… Wide spectrum of Key Performance Indicators
Reliability analysis
Consequence analysis
10Hugo Guimarães / Risk analysis of bridges using a new reliability-based robustness assessment methodology
Metamodeling for Reliability Analysis
Model Evaluation
Initial Design of Experiments
Model Selection and Model Fitting
Convergence
DoE
Metamodel Goal
Region of Interest Updating DoE
Model Validation
… More than 40 papers were reviewed! “Metamodeling-based methods for reliability analysis: a comparative review and insights for future developments” will be submitted to Reliability engineering and System Safety
11Hugo Guimarães / Risk analysis of bridges using a new reliability-based robustness assessment methodology
Metamodels
Response Surface Methods
Kriging or Gaussian Process
Artificial Neural Networks (ANN)
Support Vector Machines (SVM)
Polynomial Chaos Expansion (PCE)
… Benchmarking methods is not a straightforward task!Still a reduced list of test examples was selected.
12Hugo Guimarães / Risk analysis of bridges using a new reliability-based robustness assessment methodology
Dynamic Problem with 6 RV
Kriging ANN SVM PCE Spline iRS
13Hugo Guimarães / Risk analysis of bridges using a new reliability-based robustness assessment methodology
3-bay 5-story Building Frame (21 RV)
PCE RSM iRS
Correlation is not efficiently addressed by existing RSM
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Developed Method - iRS
… Main features• Optimized DoE• Double weighted regression technique• Stepwise Selection• Region of Interest• Cross-Validation• CI based on bootstrapping
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Structural Performance Assessment
Definition Limit State Function
Reliability Analysis
Performance Assessment
𝐺 𝑋 = ⋯ 𝑃& = 𝑃(𝐺 𝑋 < 0) 𝛽 < 𝛽,-./0,
Deflection control Crack controlStress level
Resistance capacityStress level
Nonlinear FE Analysis
iRS method Code-basedRecommendation
16Hugo Guimarães / Risk analysis of bridges using a new reliability-based robustness assessment methodology
Transportation Network
Normalized risk indicator which considers consequences of disruption
Sabatino (2015a, 2015b)
Maximum admissible direct losses: % annual budget for maintenance
Maximum admissible indirect losses: % GDP of affected region
17Hugo Guimarães / Risk analysis of bridges using a new reliability-based robustness assessment methodology
Transportation NetworkInsignificantConsiderableSeriousSevere
Very Likely (50-100%)
Likely (30-50%)
Occasional (10-30%)
Unlikely (0-10%)
Negligible - 1Acceptable - 0,8Controllable - 0,6Critical - 0,2Unacceptable - 0
Disastrous
Ruan et al. (2015a)
Utility indifference curves for risk-averse attitude
18Hugo Guimarães / Risk analysis of bridges using a new reliability-based robustness assessment methodology
Case studies… Short-span RC bridge studied by Wong et al. (2005)
1. Several numerical difficulties were encountered using classical RSM (Wong et al. 2005)
2. Typical configuration of highway overpasses
3. Life-cycle performance assessment
19Hugo Guimarães / Risk analysis of bridges using a new reliability-based robustness assessment methodology
Simply supported girder bridge
0
1
2
3
4
5
0 20 40 60 80
Relib
ailityIndex
TimesinceCorrotionInitiation[years]
Onlycorrosion OnlyLiveLoad
BothCorrosionandLiveLoad
-2
-1
0
1
2
3
4
5
0 20 40 60 80
Relib
ailityIndex
TimesinceCorrotionInitiation[years]
Onlycorrosion Failure ofExterior Girder
βsys
βdam
Target reliability based on Ghosn and Yang (2014)NCHRP Report 776
LLXLFXG −= )()(
20Hugo Guimarães / Risk analysis of bridges using a new reliability-based robustness assessment methodology
Simply supported girder bridge
0
1
2
3
4
5
6
0 20 40 60 80
Relib
ailityIndex
ServiceTime[years]
Onlycreep andshrinkage Corrosion (low intensity)
βserv = 1.3EN-1990 (2002)]
JCSS (2001) and ISO2394 (2015)
βserv = 1.5
21Hugo Guimarães / Risk analysis of bridges using a new reliability-based robustness assessment methodology
Tercenas Bridge
22Hugo Guimarães / Risk analysis of bridges using a new reliability-based robustness assessment methodology
Tercenas Bridge
2
3
4
5
6
0 5 10 15 20 25 30
Relib
ailityIndex
TimesinceCorrotionInitiation[years]
CorrosiononlyG1 General Corrosion
βsys
0
1
2
3
4
5
6
0 5 10 15 20 25 30
Relib
ailityIndex
TimesinceCorrotionInitiation[years]
CorrosiononlyG1 Failure Exterior Girder
βdam
The structure presents a satisfactory reserve capacity and redundancy.
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Comparing PerformanceSimply supported bridge Tercenas Bridge
24Hugo Guimarães / Risk analysis of bridges using a new reliability-based robustness assessment methodology
Additional Contributions
Risk-informed decision making
25Hugo Guimarães / Risk analysis of bridges using a new reliability-based robustness assessment methodology
Conclusions
Risk-informed decision making• Research needs vs Research Goals
• Challenges and solutions in metamodeling-based reliability
• Alternative approach to prioritize maintenance actions in bridges
• Contributions to academical and practical environment
26Hugo Guimarães / Risk analysis of bridges using a new reliability-based robustness assessment methodology
Future Developments and suggestions to research
Risk-informed decision making• Introducing clustering algorithms to deal with multiple failure modes
• Performance metrics at network level can still be improved and include
probabilistic nature (flow-based and topology-based)
• Extend and disseminate developed software
• Include multiobjective optimization in the proposed framework