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Framework for Assessment of State Performance and Management of Canada’s Core Public Infrastructure (CPI) Review of State- of- Art Meeting of the National Round Table on Sustainable Infrastructure March 26, 2008, Toronto
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Outline Background Review of performance assessment of CPI Knowledge “deficit” in performance assessment Approach
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Background CPI: roads, bridges, transit, water and wastewater systems Canada’s CPI enable: –personal mobility –transport of people and goods, –provide safe drinking water –remove wastes –critical to competitiveness of economy and quality of life NRC Cross-Canada Tour- Concerns of decision-makers: –aging infrastructure –lack of reliable performance data –ill-defined acceptable minimum levels of performance –few management tools –PSAB 3150 requirements –ineffective communications to decision makers –closing small towns, concerns of northern communities –Environment now on agenda- Sustainability concerns
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Decreasing Capacity / Increasing Risk of Failure Consequences: Health & Safety problems Economic & Social impacts Environmental impact Background Inadequate Performance Assessment + Deterioration of Core Public Infrastructure Aggressive Environment Climate Change Aging CPI Systems Increasing Demand
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Background Life cycle management of CPI = challenging problem Optimize allocation of funds for maintenance, rehabilitation & renewal for different CPI systems, given: –large network of CPI systems and components –CPI systems/components deteriorate with time –risk of failure increases with time –lack of reliable data on current and future state of systems –different assets with different consequences of failure –limited funds Challenges
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Safety –load rating, load carrying capacity, reliability index –condition rating, sufficiency rating, appraisal rating, health index Serviceability –condition rating –excessive stresses, cracking, deformation, vibration Fatigue Functionality –condition rating, sufficiency rating –bridge width, vertical/horizontal clearances Performance Indicators – Bridges CPI Performance Assessment
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Performance Indicators - Bridges CPI Performance Assessment 9 to 0 (excellent, very good, …, imminent, failed) Three general ratings (deck, superstructure and substructure) Appraisal ratings Sufficiency rating SD/FO classification AASHTO (CoRe elements) FHWA AgencyCondition rating system Pontis: 1 to 5 or 1 to 3 Based on detailed element-level inspection (one rating per element type) Performance Indicator Appraisal ratings Sufficiency rating SD/FO classification Health Index (CalTrans) Canada (e.g. MTO) Four conditions states : excellent, good, fair and poor Based on detailed element-level inspection (one rating per element type) Bridge condition index (BCI) Bridge sufficiency index (BSI)
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Riding comfort index Surface distress index Structural adequacy index Pavement condition index International roughness index Pavement quality index Performance Indicators - Roads CPI Performance Assessment
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Performance Indicators - Roads CPI Performance Assessment AgencyPerformance IndicatorsEvaluation MTO- Ride Condition Rating (RCR) - Pavement distress severity and extent - Pavement condition index (PCI) 0-10 (very poor to excellent) 6 severity levels, extent in % 0-100 (poor to excellent ) MTQ -International roughness index (IRI) -Rutting -Pavement cracking Engineering units (m/km) Rutting depth 0-100 (poor to excellent) Three ratings : wheel path, transverse cracking and general condition Alberta -IRI -Surface distress index (SDI) -Structural adequacy index (SAI) -Pavement quality Index (PQI) Engineering units (m/km) FHWA IRI Present serviceability rating (PSR) Engineering units (m/km) 0-5 (subjective rating)
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1)Point of Entry (POE) and distribution guidelines 2)Customer Satisfaction 1)Residual Chlorine 2)Customer complaints (#) 3)Boil water advisories (# / time) 4)… Hydraulic and Quantity of flow Water Quality Failure Criteria Sub Criteria 1)Adequate Pressure 2)Fire Fighting Capability 3)Emergency Storage 4)Adequate Capacity 5)Customer Satisfaction Performance Indicator 1)Flow velocity (max) 2)Pressure (min/max) 3)Water age (>1 day) 4)Demand (average, peak) 5)Pumps and storage capacity 6)Water consumption/capita 7)Low Pressure Complaints … System Integrity 1)Minimize # and Duration of Interruptions 2)Minimize Response Time 3)Minimize Non-Revenue Water 4)Maximize Efficiency 1)# of Breaks (normalized) 2)# of Leaks (normalized) 3)Amount Non-Revenue Water 4)# Service interruptions 5)… CPI Performance Assessment Performance Indicators – Water Systems
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1)Effluent guidelines 2)Customer Satisfaction 1)Fecal Coliform Count 2)Sewer bypass (#) 3)Sewer overflows (#) 4)… Hydraulic and Quantity of flow Quality Sanitary/Storm 1)Adequate Flow 2)Emergency Overflow 3)Adequate Capacity 4)Customer Satisfaction 1)Flow velocity (min/max) 2)Average daily flow 3)Pumps and storage capacity 4)Wastewater produced/capita 5)… System Integrity 1)Blockages and backups (#) 2)Collapses (#) 3)I & I (% or amount) 4)Sewage flooding incidents due to capacity and blockages (#) 5)Service interruptions (#) 6)Pollution incidents (#, Severity) 7)… Failure CriteriaSub Criteria Performance Indicator 1)Minimize # and Duration of Interruptions 2)Minimize Response Time 3)Maximize Efficiency CPI Performance Assessment Performance Indicators – Wastewater Systems
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1)Managing breaks for small diameter distribution systems 2)Transmission Trunks (Large Diameter) use Structural distress indicators (NRC- AwwaRF) 1)WRc Condition Grade (1-5 Defect-based) –Structural (Physical Condition) –Operational (Blockages and Infiltration) 2)NRC Trunk Sewers Guidelines (Defects) 3)National Association of Sewer Service Contractors - NASSCO (Simplified WRc) 4)North American Association of Pipeline Inspectors – NAAPI (Simplified WRc) WaterSanitary and Storm Water CPI Performance Assessment Performance Indicators – Water & Wastewater Systems
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State-of-art deterioration prediction models are based on Markov chain models : –qualitative prediction of future performance based on ratings –modeling of cumulative damage only – No “shock” modeling –assumption of constant rate of deterioration - Not realistic at all ! –no information on residual capacity and safety –predicted service life is a rough approximation –‘true” condition can be seriously overestimated – disaster! –examples of decision support systems: “Pontis”, “Bridgit”, etc. Deterioration Prediction Models CPI Performance Assessment
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Same bridges rated by different inspectors : – up to 5 rating points difference! (FHWA 2000) –unacceptable for such critical structures! –predicted remaining life is arbitrary and may lead to unsafe estimates- disasters (loss of life, injuries, economic impacts, etc.) Reliability of Performance Indicators- Examples Same bridge can be rated by 3 different inspectors as either: –Serious condition – Probability of collapse could be 0.01 –Fair condition - Probability of collapse could be 0.05 –Critical condition - Probability of collapse could be 0.1 Unacceptable for safety-critical systems CPI Performance Assessment
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Reliability of Performance Indicators- Examples CPI Performance Assessment I35 bridge superstructure: –bridge opened to traffic in 1967 –rated “Poor” not “Critical” –scheduled for reconstruction in 2020-25 –estimated Remaining Life 12-15 years Condition Rating 4 2 0 3 Poor Serious Critical Imminent failure Failed 1 Probability of failure ? ? ? 1 ? ? –bridge collapsed 2 years after evaluation !
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Current performance assessment is mainly qualitative Focus on material distresses instead of system distresses Based on “visual” inspection + some non-destructive techniques –mapping observed material distresses to subjective rating scales Arbitrary definition of minimum performance or failure criteria No differentiation between safety-critical and secondary systems Limited or no quantitative data on: –residual capacity, safety –probability of failure and risk of failure –remaining life Summary CPI Performance Assessment
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“Knowledge Deficit” in CPI Performance Assessment Time (years) Performance Life cycle Residual life Limit state/ acceptable minimum performance Service life 1 Cumulative damage “wear & tear” Service life 2 Repair/Rehab/Replace Random shock- induced damage Service life 3
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Quantitative Measures of CPI Performance - Examples Load Capacity Initial capacity Time-decreasing capacity Time Time-varying probability of failure “Knowledge Deficit” in CPI Performance Assessment Performance= Capacity – Load Performance= Capacity / Load Performance= Probability that Capacity is higher than Load
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Develop rational and objective acceptable minimum levels of performance or limit states considering: –type of CPI system and component –consequences of failure/ importance/ criticality of CPI system: e.g. loss of life, health/ injury risks, property loss, environmental impact –type of failure mode: ductile / progressive or brittle / sudden –design life of CPI system/ component Acceptable Minimum Levels of Performance “Knowledge Deficit” in CPI Performance Assessment
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Risk of failure enables decision makers to : –identify critical / high priority components of CPI –Integrate management of different CPI systems Quantifying Risk of Failure of CPI “Knowledge Deficit” in CPI Performance Assessment CPI Project Management CPI Network Management Integrated CPI Management Develop approaches to assess risk of failure of CPI systems: Risk of failure = Probability of Failure X Consequences of failure
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Build on existing knowledge and best practices Advance state of knowledge using sound scientific and engineering approaches and develop: –reliable and practical performance assessment of CPI systems –objective minimum performance levels –“unified” or “model” CPI performance indicators and measures Promote adoption and implementation of developed approaches for CPI performance assessment and management Approach
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NRC and NRTSI will collaborate on research projects: –Phase 1: Development of a framework for assessment of state, performance and management of CPI –Phase 2: Development of approaches and tools for performance assessment and management of CPI Benefits –ensure safety and health of Canadians –improve the performance of Canada’s CPI –support decision making at all levels of government –reduce economic, environmental, and social impacts of CPI –evaluate impact of funding on performance of CPI Approach
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Questions? Zoubir Lounis, Ph.D., P. Eng. Zoubir.Lounis@nrc.gc.ca Tel: (613) 993-5412
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