UIM, Dec 9, 2008 Criticality and Prioritization of Pipe Rehab Projects Annie Vanrenterghem Raven,...
-
Upload
john-lawson -
Category
Documents
-
view
218 -
download
1
Transcript of UIM, Dec 9, 2008 Criticality and Prioritization of Pipe Rehab Projects Annie Vanrenterghem Raven,...
UIM, Dec 9, 2008
Criticality and Prioritization of
Pipe Rehab Projects
Annie Vanrenterghem Raven, Ph.D.Research Associate ProfessorPolytechnic Institute of NYU
UIM, Dec 9, 20082
Assignment
Choose best pipes candidates for rehab for the next year (short term) given a certain budget.
UIM, Dec 9, 20083
Constraints
Several thousands of miles of pipes
Limited budget
Many criteria to take into account
Choices will have to be justified
UIM, Dec 9, 20084
Water and Waste Water Rehabilitation Planning
BuriedNetwork
BuriedNonNetwork
Above groundNetwork
Above GroundNon network
Water Pipes Valves; fittings
Hydrants;Manholes
Plant; Pumping Station
WasteWater Sewer
Storm Water
Storm
Drains
UIM, Dec 9, 20085
Points of View
Points of view:Time: long term and next year/short term
Space: whole system; zone; cohort of pipes; pipe level
Prioritize or optimize
Problems to address:StructuralWater qualityHydraulic (adequate pressure)
UIM, Dec 9, 20086
Other Points of View
Points of view:Time: long term and next year/short term
Space: whole system; zone; cohort of pipes; pipe level
Prioritize or optimize
Problems to address:StructuralWater qualityHydraulic (adequate pressure)
UIM, Dec 9, 20087
Performance
Indicators=
Prioritize problems
Zonescohorts
Long-Term Rehabilitati
on Planning
= Design CIPBased on stock and
degradation
HydraulicCriticality
and Vulnerability
Failure Forecastin
g=
Calculate the
probability of failure for each year and each pipe
Annual Rehabilitation
Planning
Macro analysisInput and output data at system, zone or cohort
level
Micro analysisInput and output data at
pipe level
The suite of tools
UIM, Dec 9, 20088
Overall Context
Legal GASB 34; no federal mandate; state or local incentives
PhysicalAssets are ageing; in need of rehab (ASCE report card: D-)Water quality problems, decrease of hydraulic capacitySystems need to grow or shrink
NaturalDrought situations make leaks and breaks unacceptable
FinancialCapital needs ( to maintain and replace existing waterinfrastructure between 2003 and 2023) expected to be $277 billion; up to 2/3 for buried assets. (U.S. EPA, 2005) Gap between projected revenues and expensesLess public funding Full cost pricing rate increasesLess demand/revenues due to conservation technologies, change in public behavior, current financial crisis.
UIM, Dec 9, 20089
Rehab planning: challenges
BuriedA lot to replace (US: 1M+ mi; LV: 4K mi; NYC: 6K mi)
Networks are scattered and ubiquitous;
even at most sensitive areas
Inspection, repair, replacement expensive and disruptiveDegradation/failure/impact unknown or very spectacular…
UIM, Dec 9, 200811
Rehab planning: challenges
Multi-problems; multi-disciplinary, complex tasks involving multiple criteria.In the past, rehabilitation decisions have been pragmatic, opportunistic, and difficult to justify. In house DSS attempts; could be quite simplistic (matrix) and erroneous. No comprehensive research in the US.Lack of trust for advanced models (“black boxes”.) Funds are limited but business case of AM is still difficult to make.
UIM, Dec 9, 200812
Rehab planning: Challenges with dataIf data does not exist, it has to be collected. Even simple solutions need data.Data is needed to populate the GIS and the HM, CMMS and AM system.Data collection is expensive. Data should be used for more than having a snap shot of the system at a given time, to set priorities.Prioritization should use the kind of advanced tools (used in other industries) that provide more answers and deal with uncertainty.This can be done at a rather low marginal cost. Added value and function to high price tools such as GIS, HM, CMMS. However the data must meet certain needs.
UIM, Dec 9, 200813
Assignment
Choose best pipes candidates for rehab for the next year (short term) given a certain budget.
UIM, Dec 9, 200814
Annual Rehab Planning
Multi-Criteria Decision Making Model (Electre) uses reference profiles to mitigate uncertainty.Criteria express risk (probability x consequences of failure) as well as other relevant points of view.Data is collected at different levels of refining.
UIM, Dec 9, 200815
Criterion name Code Definition
Coordination with Other Infrastructure Co-ordination Score COS Score [-1,1]
Repair CostsAnnual Repair Cost
ARC ARC(i) = PFR(i) x UCRp(i)
Water Loss Water Losses Index WLI Index [0,1]
Water Interruptions
Predicted Water Interruptions PWI PWI(i) = PFR(i) x EDI(i) x NPS(i)
Predicted Critical Water Interruptions PCWI PCWI(i) = PFR(i) x EDI(i) x SC(i)
Predicted Frequency of Water Interruptions PFWI
PFWI(i) = L (i)/100 x PFR(i) x EDI(i)
Damages and Disruptions
Damages due to Flooding in Housing areas DFH
DFH(i) = PFR(i) x DI^2(i) x P(i) x SFH(i)
Damages due to Flooding in Industrial or commercial areas DFI
DFI(i) = PFR(i) x DI^2(i) x P(i) x SFI(i)
Damages due to Soil Movement DSM
DSM(i) = PFR(i) x DI^2(i) x P(i) x LS(i)
Traffic Disruption DT DT (i) = PFR(i) x SR(i)
Damages and/or Disruption on other Infrastructure DDI
DDI(i) = PFR(i) x DI^2(i) x P(i) x SI(i)
Water Quality Water Quality Deficiencies WQD Index [0,1]
Hydraulic Criticality
Hydraulic Criticality Index HCI Index [0,1]
UIM, Dec 9, 200816
Criterion nameCode Definition
Coordination with Other Infrastructure Co-ordination Score COS Score [-1,1]
Repair CostsAnnual Repair Cost
ARC ARC(i) = PFR(i) x UCRp(i)
Water Loss Water Losses Index WLI Index [0,1]
Water Interruptions
Predicted Water Interruptions PWI PWI(i) = PFR(i) x EDI(i) x NPS(i)
Predicted Critical Water Interruptions PCWI PCWI(i) = PFR(i) x EDI(i) x SC(i)
Predicted Frequency of Water Interruptions PFWI
PFWI(i) = L (i)/100 x PFR(i) x EDI(i)
Damages and Disruptions
Damages due to Flooding in Housing areas DFH
DFH(i) = PFR(i) x DI^2(i) x P(i) x SFH(i)
Damages due to Flooding in Industrial or commercial areas DFI
DFI(i) = PFR(i) x DI^2(i) x P(i) x SFI(i)
Damages due to Soil Movement DSM
DSM(i) = PFR(i) x DI^2(i) x P(i) x LS(i)
Traffic Disruption DT DT (i) = PFR(i) x SR(i)
Damages and/or Disruption on other Infrastructure DDI
DDI(i) = PFR(i) x DI^2(i) x P(i) x SI(i)
Water Quality Water Quality Deficiencies WQD Index [0,1]
Hydraulic Criticality
Hydraulic Criticality Index HCI Index [0,1]
UIM, Dec 9, 200817
Criterion name Code Definition
Coordination with Other Infrastructure Co-ordination Score COS Score [-1,1]
Repair CostsAnnual Repair Cost
ARC ARC(i) = PFR(i) x UCRp(i)
Water Loss Water Losses Index WLI Index [0,1]
Water Interruptions
Predicted Water Interruptions PWI PWI(i) = PFR(i) x EDI(i) x NPS(i)
Predicted Critical Water Interruptions PCWI PCWI(i) = PFR(i) x EDI(i) x SC(i)
Predicted Frequency of Water Interruptions PFWI
PFWI(i) = L (i)/100 x PFR(i) x EDI(i)
Damages and Disruptions
Damages due to Flooding in Housing areas DFH
DFH(i) = PFR(i) x DI^2(i) x P(i) x SFH(i)
Damages due to Flooding in Industrial or commercial areas DFI
DFI(i) = PFR(i) x DI^2(i) x P(i) x SFI(i)
Damages due to Soil Movement DSM
DSM(i) = PFR(i) x DI^2(i) x P(i) x LS(i)
Traffic Disruption DT DT (i) = PFR(i) x SR(i)
Damages and/or Disruption on other Infrastructure DDI
DDI(i) = PFR(i) x DI^2(i) x P(i) x SI(i)
Water Quality Water Quality Deficiencies WQD Index [0,1]
Hydraulic Criticality
Hydraulic Criticality Index
HCI Index [0,1]
UIM, Dec 9, 200818
Criteria, example PWI
PWI(i) = PFR(i) x EDI(i) x NPS(i)Units: (No./mile/year) x (hours) x (persons)
With:PFR (i) Predicted Failure Rate for pipe i (No./mile/year)EDI (i) Expected Duration of Interruption (hours) NPS (i) Number of Customers Supplied by pipe (i) (or by all pipes that will be affected by the interruption of service; using hydraulic criticality results )
UIM, Dec 9, 200819
Criteria, example ARC
ARC (i) = PFR (i) x UCRp(i)
Units: (No./100m/year) x ($)
With :
PFR (i) Predicted Failure Rate for pipe i (No./mile/year)UCRp (i) is the Unit Cost of Repair ($)
UIM, Dec 9, 200820
Knowledge base, example UCR
Code Cost Description
1 3000 Unknow
2 1900 Diam <12” & easy context
3 3100 Diam <12” & normal context orDiam >12” & easy context
4 4700 Diam >12” & normal context orDiam <12” & difficult context
5 6200 Diam >12” difficult context
UIM, Dec 9, 200824
The categories
C33: Pipes with highest priority level. Pipes have been assigned to C3 according to both OP and PP.C32 (or C31): No consensus among criteria may be due to incomparability.C31, C22, C21, C11: low and moderate performance deficiencies.
UIM, Dec 9, 200827
Performance
Indicators=
Prioritize problems
Zonescohorts
Long-Term Rehabilitati
on Planning
= Design CIPBased on stock and
degradation
HydraulicCriticality
and Vulnerability
Failure Forecastin
g=
Calculate the
probability of failure for each year and each pipe
Annual Rehabilitation
Planning
Macro analysisInput and output data at system, zone or cohort
level
Micro analysisInput and output data at
pipe level
The suite of tools
UIM, Dec 9, 200828
Failure ForecastingHydraulic criticality
FF = Calculate Probability of each pipe for each year (PHM, LEYP)Hydraulic criticality and vulnerability
Effect of one pipe being out of service on delivery of service in rest of systemEffect of each pipe being out of service on one specific pipe2 pipes being out of service
UIM, Dec 9, 200829
Performance
Indicators
Long-Term Rehabilitati
on Planning
HydraulicCriticality
and Vulnerability
Failure Forecastin
g
Annual Rehabilitation
Planning
Macro analysisInput and output data at system, zone or cohort
level
Micro analysisInput and output data at
pipe level
Implication of Polytechnic University