Session 5 Techniques for Determining Pavement/ Treatment Feasibility.

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


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


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

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air

Sea

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oat

Mic

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icro

Sur

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Col

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Rec

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Sur

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Mill

Sur

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Mill

Thi

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verla

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FD

Mill

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D M

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Par

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/LP

art M

ill &

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Rec

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Rec

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Cra

ck F

illin

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rack

Fill

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Rut

Mill

Rut

Mill

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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


SevereSevere

InsufficientInsufficientStructureStructure

MinorMinor RLRL 2-62-6 5-85-8


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

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urfa

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Sur

face

Col

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Rec

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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

Session 5 Techniques for Determining Pavement/ Treatment Feasibility.

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Transcript of Session 5 Techniques for Determining Pavement/ Treatment Feasibility.