session 5 techniques for determining pavement/ treatment feasibility
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Session 5Session 5
Techniques for Techniques for Determining Pavement/ Determining Pavement/
Treatment FeasibilityTreatment Feasibility
Learning ObjectivesLearning Objectives
1.1. State steps in the treatment State steps in the treatment selection processselection process
2.2. List advantages and List advantages and disadvantages of decision trees disadvantages of decision trees and matricesand matrices
Upon completion of this module, you Upon completion of this module, you will be able to:will be able to:
Learning Objectives (cont.)Learning Objectives (cont.)
3.3. Identify cost analysis toolsIdentify cost analysis tools
4.4. Use LCC and cost/effectiveness to Use LCC and cost/effectiveness to evaluate strategiesevaluate strategies
Is this pavement a Is this pavement a good candidate for good candidate for PM? PM?
If so, how do I If so, how do I determine what PM determine what PM treatments to treatments to apply… and when?apply… and when?
Selecting Pavements & PM Selecting Pavements & PM TreatmentsTreatments
1.1. Gather informationGather information
2.2. Assess conditionAssess condition
3.3. Evaluate dataEvaluate data
4.4. Identify/project pavement needsIdentify/project pavement needs
5.5. Identify feasible PM treatmentsIdentify feasible PM treatments
6.6. Conduct cost/effectiveness analysisConduct cost/effectiveness analysis
7.7. Select “best” strategySelect “best” strategy
Step 1. Gather/Review Step 1. Gather/Review Available Pavement Available Pavement
InformationInformation Pavement typePavement type
Pavement age vs. design lifePavement age vs. design life
TrafficTraffic
EnvironmentEnvironment
Structure and materialsStructure and materials
Construction qualityConstruction quality
Step 2. Assess Current Step 2. Assess Current Pavement ConditionPavement Condition
Identify current distresses (severity Identify current distresses (severity and amount)and amount)
Is the pavement in relatively “good” Is the pavement in relatively “good” condition?condition?
Are there any structural failures?Are there any structural failures?
Minimal previous repairs?Minimal previous repairs?
Step 3. Evaluate DataStep 3. Evaluate Data
Too much distress?Too much distress?
Underlying structural problems?Underlying structural problems?
Missed PM “window of opportunity?” Missed PM “window of opportunity?”
Material or construction problems?Material or construction problems?
Problems in this environment?Problems in this environment?
Typical performance of this type of Typical performance of this type of pavement?pavement?
Step 4. Identify/Project Step 4. Identify/Project Pavement NeedsPavement Needs
A.A.Identify current pavement needsIdentify current pavement needs
Preservation? Maintain or reach acceptable LOS?
B.Anticipate potential future problems (structural, functional)
Step 5. Identify Feasible PM Step 5. Identify Feasible PM TreatmentsTreatments
Characteristics Influencing Characteristics Influencing Feasible AlternativesFeasible Alternatives
Pavement typePavement type TrafficTraffic EnvironmentEnvironment Past treatment performancePast treatment performance Ease of applicationEase of application CostCost Material and contractor availabilityMaterial and contractor availability
Existing Methods of Identifying Existing Methods of Identifying Feasible AlternativesFeasible Alternatives
Lists of acceptable treatmentsLists of acceptable treatments
Time-based schedulesTime-based schedules
Decision toolsDecision tools Decision treesDecision trees Decision matricesDecision matrices
Lists of Agency-Accepted Lists of Agency-Accepted Treatment TypesTreatment Types
Agency PM guidelinesAgency PM guidelines
Organized by categoryOrganized by category Pavement typePavement type Traffic levelTraffic level Pavement conditionPavement condition Others?Others?
MichiganMichiganAcceptable PM TreatmentsAcceptable PM Treatments
Rigid PavementsRigid Pavements Full-depth repair Joint resealing Crack sealing Joint & surface spall
repair Dowel bar retrofit Diamond grinding Underdrain outlet repair
and cleaning CPR Bit. shoulder ribbons
Flexible and Comp. Pvmts.Flexible and Comp. Pvmts. Bituminous overlay Milling & bit. overlay Ultra thin overlay Crack treatment Overband crack filling Microsurfacing Chip seals Bit. shoulder ribbons Shoulder seals Paver placed surface seals Hot in-place bit. recycling
Time-Based SchedulesTime-Based Schedules Set schedule of PM treatmentsSet schedule of PM treatments
Based on pavement type and ageBased on pavement type and age
Corrections?Corrections?
Time-Based Schedule ExampleTime-Based Schedule ExampleNew York State-Initial GuidelinesNew York State-Initial Guidelines
Treatment TypeTreatment TypeAppl. Appl.
Cycle, yrsCycle, yrs PCC pavement joint and crack sealingPCC pavement joint and crack sealing HMA pavement crack sealingHMA pavement crack sealing Thin HMA overlays (38 mm [1.5 in])Thin HMA overlays (38 mm [1.5 in]) Surface treatments of HMA Surface treatments of HMA
pavementspavements Surface treatments of shouldersSurface treatments of shoulders Clean drainageClean drainage
8844
12124444
1010
Time-Based Schedule ExampleTime-Based Schedule ExampleProvince of Ontario (Freeways)–PCCProvince of Ontario (Freeways)–PCC
Design Design Life (yrs)Life (yrs)
Year of Year of TreatmentTreatment Maintenance TreatmentMaintenance Treatment
2020 101015152020
Reseal 10% of all jointsReseal 10% of all jointsReseal 20% of all jointsReseal 20% of all jointsREHABILITATIONREHABILITATION
2525 1010151520202525
Reseal 10% of all jointsReseal 10% of all jointsReseal 20% of all jointsReseal 20% of all jointsReseal 20% of all jointsReseal 20% of all jointsREHABILITATIONREHABILITATION
Other Time-Based ExamplesOther Time-Based Examples
South DakotaSouth Dakota Crack sealing: 1 to 2 yearsCrack sealing: 1 to 2 years Chip seal: 3 yearsChip seal: 3 years
MontanaMontana Chip seal: 6 to 8 yearsChip seal: 6 to 8 years Thin overlay: 10 to 12 yearsThin overlay: 10 to 12 years
Decision Trees / MatricesDecision Trees / Matrices Identify one or more acceptable PM Identify one or more acceptable PM
treatmentstreatments
Consider characteristics such as:Consider characteristics such as: Pavement typePavement type Distress type and level, or index Distress type and level, or index
valuesvalues Traffic volumeTraffic volume Functional classificationFunctional classification
HMA Decision Tree HMA Decision Tree ExampleExample
Prev. Maint. Treatment
Surface Wear Severity
Env. Cracking Extent
Fatigue Crack Extent
Rutting Severity
Structural Deterioration
Crack Seal
Surface Treatment
Crack Seal + 40 mm O/L
Crack Seal
Crack Seal + 40 mm O/L
Mill and Fill50 mm
Mill and Fill40 mm
Mill and Fill50 mm
Mill and Fill50 mm
Prev. Maint. Treatment
Mill and Fill40 mm
Mill and Fill50 mm
Mill and Fill75 mm
Mill 50 mm +75 mm O/L
Mill 75 mm +100 mm O/L
Mill 100 mm + 125 mm O/L
Mill 100 mm + 150 mm O/L
Total Reconstruct
Rem. HMA, Rep Base, Repave
Low
Moderate
High
Low
Moderate
High
Low
Moderate
High
Low
Moderate
High
Low
Moderate
High
Low
Moderate
High
Low
Moderate
High
Low
Moderate
High
YesNo
Fog Sealor
Chip Seal
Fog Sealor
Chip Sealor
Microsurfacing
Fog Sealor
Microsurfacing
ADT
<1000 1000 to 5000 >5000
HMA Decision Tree Example HMA Decision Tree Example Raveling and WeatheringRaveling and Weathering
Not Appropriate forPreventive
Maintenance
Structural Condition
AdequateNot
Adequate
HMA Decision Matrix ExampleHMA Decision Matrix Example
DistressDistress SeveritySeverity
Treatment TypeTreatment Type
Flushing/Flushing/BleedingBleeding
ModerateModerate N/AN/A RLRL RLRL
SevereSevere RLRL RLRL RLRL 10-1210-12
Non-Structural Non-Structural CrackingCracking
MinorMinor N/AN/A 3-53-5 3-53-5
ModerateModerate 3-53-5 6-96-9 8-108-10 3-53-5
SevereSevere 8-128-12 8-108-10 12-1512-15 FLFL
InsufficientInsufficientStructureStructure
MinorMinor RLRL 2-62-6 5-85-8 2-62-6 4-84-8
ModerateModerate 2-62-6 2-62-6 4-84-8 8-128-12 12-1512-15 FLFL
SevereSevere 8-128-12 12-1512-15 FLFL
Bad RideBad Ride
MinorMinor N/AN/A RLRL RLRL
ModerateModerate RLRL 8-108-10 10-1210-12
SevereSevere RLRL 12-1512-15 10-1210-12
Unstable Base Unstable Base and Subgradeand Subgrade
MinorMinor RLRL 2-62-6 2-62-6 4-84-8
ModerateModerate 5-85-8 2-62-6 4-84-8 8-128-12 12-1512-15
SevereSevere 8-128-12 10-1210-12 12-1512-15 FLFL
Unstable MixUnstable Mix
MinorMinor 5-85-8 2-62-6 6-106-10 8-128-12
ModerateModerate 8-128-12 FLFL
SevereSevere 8-128-12 FLFL
AgedAgedPavementPavement
MinorMinor 4-84-8 3-63-6 2-62-6
ModerateModerate 5-105-10 2-62-6 6-106-10 8-128-12 8-128-12
SevereSevere 8-128-12 8-128-12 12-1512-15 FLFL
Surface Surface RavelingRaveling
MinorMinor N/AN/A
ModerateModerate 3-63-6
SevereSevere 8-128-12
Do
Not
hing
Do
Not
hing
Spo
t Rep
air
Spo
t Rep
air
Sea
l Coa
tS
eal C
oat
Mic
ro S
urfa
ceM
icro
Sur
face
Col
d R
ecyc
leC
old
Rec
ycle
Sur
face
Mill
Sur
face
Mill
Thi
n O
verla
yT
hin
Ove
rlay
FD
Mill
& O
/LF
D M
ill &
O/L
Par
t Mill
& O
/LP
art M
ill &
O/L
Rec
onst
ruct
Rec
onst
ruct
Cra
ck F
illin
gC
rack
Fill
ing
Rut
Mill
Rut
Mill
Thi
ck O
verla
yT
hick
Ove
rlay
DistressDistress SeveritySeverity
Treatment Number and TypeTreatment Number and Type
Flushing/Flushing/BleedingBleeding
ModerateModerate N/AN/A RLRL RLRL RLRL
SevereSevere
Non-Structural Non-Structural CrackingCracking
MinorMinor N/AN/A 3-53-5
ModerateModerate 3-53-5
SevereSevere
InsufficientInsufficientStructureStructure
MinorMinor RLRL 2-62-6 5-85-8
ModerateModerate 2-62-6
SevereSevere
Bad RideBad RideMinorMinor N/AN/A RLRL
ModerateModerate
SevereSevere
Do
Not
hing
Do
Not
hing
Spo
t R
epai
rS
pot
Rep
air
Sea
l Coa
tS
eal C
oat
Mic
ro S
urfa
ceM
icro
Sur
face
Col
d R
ecyc
leC
old
Rec
ycle
HMA Decision Matrix ExampleHMA Decision Matrix ExampleSeal CoatSeal Coat Slurry SealSlurry Seal MicrosurfacingMicrosurfacing
TrafficTraffic
ADT<2000ADT<2000
2000>ADT<50002000>ADT<5000
ADT>5000ADT>5000
RR
MM
NRNR
RR
MM
NRNR
RR
RR
RR
BleedingBleeding RR RR RR
RuttingRutting NRNR RR RR
RavelingRaveling RR RR RR
CrackingCrackingFew tight cracksFew tight cracks
Extensive crackingExtensive crackingRR
RRRR
NRNRRR
NRNR
Improving FrictionImproving Friction YesYes YesYes YesYes
Snow Plow DamageSnow Plow Damage Most Most susceptiblesusceptible
Moderately Moderately susceptiblesusceptible
Least Least susceptiblesusceptible
R = Recommended; NR = Not recommended; M = MarginalR = Recommended; NR = Not recommended; M = Marginal
Benefits of Decision Benefits of Decision Trees/MatricesTrees/Matrices
Make use of existing experienceMake use of existing experience
Work well for local conditionsWork well for local conditions
Good as a project-level toolGood as a project-level tool
Limitations of Decision Limitations of Decision Trees/MatricesTrees/Matrices
Transferability between agenciesTransferability between agencies Limits innovationLimits innovation Does not incorporate all factorsDoes not incorporate all factors Difficulty with multiple distress typesDifficulty with multiple distress types Does not identify most cost-effective Does not identify most cost-effective
strategystrategy Not good for network evaluationNot good for network evaluation
Developing Decision ToolsDeveloping Decision ToolsConsiderationsConsiderations
Select treatments for pavement typesSelect treatments for pavement types Identify criteria that affect feasibilityIdentify criteria that affect feasibility
Pavement agePavement age Key distressesKey distresses
Structural vs. functionalStructural vs. functional Threshold levelsThreshold levels
Traffic volumesTraffic volumes
Developing Decision ToolsDeveloping Decision ToolsClass ExerciseClass Exercise
1.1. Pick a pavement typePick a pavement type
2.2. Select typical or desired treatmentsSelect typical or desired treatments
3.3. Identify criteria that affect feasibilityIdentify criteria that affect feasibility
4.4. Create a decision matrixCreate a decision matrix
5.5. Create a decision treeCreate a decision tree
Step 6. Conduct Step 6. Conduct Cost/Effectiveness Cost/Effectiveness
AnalysisAnalysis
Cost/Effectiveness Cost/Effectiveness Analysis Analysis IntroductionIntroduction
Determine treatment costs and life Determine treatment costs and life expectancy data for YOUR agencyexpectancy data for YOUR agency Previous projectsPrevious projects Pavement management recordsPavement management records
Different cost and cost-effectiveness Different cost and cost-effectiveness analysis approachesanalysis approaches
Assessment of cost-effectiveness Assessment of cost-effectiveness requires determination of benefitsrequires determination of benefits
Common Cost Analysis Common Cost Analysis MethodsMethods
Equivalent annual cost (EAC) Equivalent annual cost (EAC)
Longevity cost indexLongevity cost index
Life cycle cost analysis (LCCA)Life cycle cost analysis (LCCA)
Benefit/cost analysisBenefit/cost analysis
Equivalent Annual CostEquivalent Annual Cost Requirements:Requirements:
Unit cost of equipment, workers, Unit cost of equipment, workers, and materials per day (or contract)and materials per day (or contract)
Expected life of treatmentExpected life of treatment
Output:Output: Unit cost per expected life of Unit cost per expected life of
treatmenttreatment
Equivalent Annual Cost Equivalent Annual Cost
unit cost of treatment
expected life, yearsEAC =
Longevity Cost IndexLongevity Cost Index Requirements:Requirements:
Treatment unit costTreatment unit cost Traffic loadingTraffic loading Treatment lifeTreatment life
Output:Output: Relates present value of treatment Relates present value of treatment
cost to life and trafficcost to life and traffic
Longevity Cost IndexLongevity Cost Index
Price/sy + MCOST/sy
Life*Annual MESALsLCI =
Longevity Cost IndexLongevity Cost Index AdvantagesAdvantages
Straightforward means of Straightforward means of determining cost effectivenessdetermining cost effectiveness
DisadvantagesDisadvantages Requires inputs that may not be Requires inputs that may not be
easy to determine (e.g., ESALs)easy to determine (e.g., ESALs) Comparing benefits?Comparing benefits?
Life Cycle Cost AnalysisLife Cycle Cost Analysis Most common approach for comparing Most common approach for comparing
alternative strategiesalternative strategies
Evaluates all costs over analysis Evaluates all costs over analysis periodperiod
Uses equivalent dollars to compare Uses equivalent dollars to compare expenses incurred at different timesexpenses incurred at different times
Does not account for varying levels of Does not account for varying levels of serviceservice
Life Cycle Cost AnalysisLife Cycle Cost AnalysisMethodsMethods
Present worth (PW)Present worth (PW)
Equivalent uniform annual cost Equivalent uniform annual cost (EUAC)(EUAC)
Life Cycle Cost AnalysisLife Cycle Cost AnalysisRequirementsRequirements
Discount rateDiscount rate
= Interest Rate – Inflation Rate= Interest Rate – Inflation Rate
Analysis periodAnalysis period
Unit cost for treatmentUnit cost for treatment
Estimated life of treatmentEstimated life of treatment
Present Worth MethodPresent Worth MethodTakes a series of costs:
And converts costs to one point in time:
$
*Comparisons require similar analysis periods
Computing Present Computing Present Worth Costs Worth Costs
PW = CPW = C1111
(1 + i)(1 + i)nn
where:where:
PWPW== Present worth costPresent worth costCC == Future costFuture costnn == Number of years Number of years (time in future when C is (time in future when C is applied)applied)ii == Discount rateDiscount rate
Equivalent UniformEquivalent UniformAnnual Cost MethodAnnual Cost Method
Takes a series of costs:
And converts costs to an equivalent series of payments:
$ $ $ $ $ $ $ $ $ $
Computing Equivalent Computing Equivalent Uniform Annual CostsUniform Annual Costs
EUAC = PWEUAC = PW i (1 + i)i (1 + i)nn
(1 + i)(1 + i)nn –– 1 1where:where:
EUACEUAC== Equivalent Equivalent uniform annual costuniform annual costPWPW == Present worth Present worth costcostnn == Analysis periodAnalysis periodii == Discount rateDiscount rate
Advantages and Advantages and Disadvantages of LCCADisadvantages of LCCA
AdvantagesAdvantages Familiar methodFamiliar method Inputs fairly easy to quantifyInputs fairly easy to quantify Variability can be evaluatedVariability can be evaluated
DisadvantagesDisadvantages Pavement condition (benefit) not Pavement condition (benefit) not
considered in analysisconsidered in analysis
Benefit/Cost AnalysisBenefit/Cost Analysis Considers both the cost and Considers both the cost and
effectiveness of a treatmenteffectiveness of a treatment
Costs determined using LCCACosts determined using LCCA
Effectiveness accounts for Effectiveness accounts for performance and users impactedperformance and users impacted
Approach is used in many PMSApproach is used in many PMS
Con
ditio
n
Benefit
What is Benefit?What is Benefit?C
ondi
tion
Benefit
Benefit = Area Time
Time
Benefit/Cost ComparisonBenefit/Cost ComparisonStrategy
Preventive Maint.
Rehabilitation
Benefit
250
1000
Cost, $M
$0.5
$3.5
2500.5
= 500PM Strategy: B/C =
10003.5
= 286Rehab Strategy: B/C =
Benefit/Cost Strategy OnBenefit/Cost Strategy OnA Network LevelA Network Level
Highest Benefit/Cost Ratios
The most cost-effective strategies are selected
Benefit/Cost AnalysisBenefit/Cost Analysis AdvantagesAdvantages
Considers costs Considers costs andand benefits benefits Use of pavement management Use of pavement management
systemssystems
DisadvantagesDisadvantages More complex than other methodsMore complex than other methods Often difficult to quantify benefits Often difficult to quantify benefits
LCCA ExampleLCCA ExampleProblem DefinitionProblem Definition
Compare two feasible PM strategies Compare two feasible PM strategies for an HMA pavement and determine for an HMA pavement and determine which has the lowest life-cycle costswhich has the lowest life-cycle costs Strategy A: Treatment 1 repeated Strategy A: Treatment 1 repeated
every 6 yearsevery 6 years Strategy B: Treatment 2 repeated Strategy B: Treatment 2 repeated
every 4 yearsevery 4 years
LCCA ExampleLCCA ExampleGeneral AssumptionsGeneral Assumptions
Benefits are considered to be the Benefits are considered to be the same for both alternativessame for both alternatives
First PM applied at year fourFirst PM applied at year four
20-year analysis periods20-year analysis periods
Routine maintenance applied Routine maintenance applied annuallyannually
User and rehab. costs not includedUser and rehab. costs not included
Gather InformationGather InformationGeneral Cost InformationGeneral Cost Information
Initial costs = $400,000 Initial costs = $400,000
Discount rate = 4%Discount rate = 4%
Gather InformationGather InformationStrategy DetailsStrategy Details
Strategy AStrategy A Treatment 1 life = 6 yearsTreatment 1 life = 6 years Treatment 1 cost = $30,000 /app.Treatment 1 cost = $30,000 /app. Annual maintenance costs = $500Annual maintenance costs = $500
Strategy BStrategy B Treatment 2 life = 4 yearsTreatment 2 life = 4 years Treatment 2 cost = $12,000 /app.Treatment 2 cost = $12,000 /app. Annual maintenance costs = $800Annual maintenance costs = $800
Cost Stream SummaryInitial Construction = $400,000 (yr 0)Treatment 1 = $30,000 (yrs 4, 10, & 16)Routine Maintenance = $500/yr (yrs 1-19)Salvage Value = (2/6)*$30,000 = $10,000 (yr 20)
Define Cost StreamsDefine Cost Streams Strategy A
0 5 10 15 20
Time
$30,000
$400,000
$500/yr
$10,000
$30,000 $30,000
Cost Stream SummaryInitial Construction = $400,000 (yr 0)Treatment 2 = $12,000 (yrs 4, 8, 12, & 16)Routine Maintenance = $800/yr (yrs 1-19)Salvage Value = $0
Define Cost StreamsDefine Cost Streams Strategy B
0 5 10 15 20
Time
$12,000
$400,000
$12,000 $12,000 $12,000
$800/yr
Compute CostsCompute CostsStrategy AStrategy A
PW (initial) = $ 400,000
PW (routine maint.) = $ 6,567
PW (treatment 1) = $ 61,928
PW (salvage value) = $ – 4,564
Total PW = $ 463,931
EUAC = $ 34,137
Discount Rate = 4%, Analysis Period = 20 yrs
Compute CostsCompute CostsStrategy BStrategy B
PW (initial) = $ 400,000
PW (routine maint.) = $ 10,507
PW (treatment 2) = $ 32,928
PW (salvage value) = $ 0
Total PW = $ 443,435
EUAC = $ 32,629
Discount Rate = 4%, Analysis Period = 20 yrs
Interpret Analysis ResultsInterpret Analysis Results
Strategy Strategy No.No.
Strategy Strategy DescriptionDescription EUACEUAC
11 Strategy AStrategy A $34,137$34,137
22 Strategy BStrategy B $32,629$32,629
Strategy B is the preventive maintenance strategy with the lower life cycle costs.
Step 7. Select “Best” Step 7. Select “Best” StrategyStrategy
Total available fundsTotal available funds
Timing considerationsTiming considerations
Cost-effectivenessCost-effectiveness
Other factorsOther factors
Review of Learning Review of Learning ObjectivesObjectives
1.1. State steps in the treatment State steps in the treatment selection processselection process
2.2. List advantages and disadvantages List advantages and disadvantages of decision trees and matricesof decision trees and matrices
3.3. Identify cost analysis toolsIdentify cost analysis tools
4.4. Use LCC and cost/effectiveness to Use LCC and cost/effectiveness to evaluate strategiesevaluate strategies
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