Life-Cycle Cost Analysis - The National Center for ......Life-Cycle Cost Analysis Evaluation of M&R...
Transcript of Life-Cycle Cost Analysis - The National Center for ......Life-Cycle Cost Analysis Evaluation of M&R...
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Life-Cycle Cost Analysis
Life-Cycle Cost Analysis
Tashia J. Clemons
FHWA Office of Asset Management
Pavement Preservation Expert Task Group Meeting
Oklahoma City, OK
May 3, 2011
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Life-Cycle Cost Analysis
Agenda
2. State Example
1. Pavement Preservation
3. Resources
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Life-Cycle Cost Analysis
Keeping Good Roads Good
Pavement Preservation
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Life-Cycle Cost Analysis
Pavement Preservation
Doing the right thing...
�at the right time...
�to the right pavement.
TO KEEP THE “GOOD” ROADS GOOD!
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Life-Cycle Cost Analysis
Case Study Section
Lake County - District 1State Route 537-mile long, 4-lane highway
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Life-Cycle Cost Analysis
Life Cycle Cost Analysis (LCCA)
• An economic analysis tool useful in comparing the relative economic merits of competing construction and rehabilitation design alternatives for a single project.
• Equivalent Uniform Annual Cost (EUAC): Represents the NPV of all discounted costs and benefits of an alternative as if they occur uniformly throughout the analysis period.
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Life-Cycle Cost Analysis
Caltrans Customized RealCost
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Life-Cycle Cost Analysis
CalME
Version 1.01
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Life-Cycle Cost Analysis
Structural Design & Economic Analysis
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Life-Cycle Cost Analysis
CalME Design Inputs
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Life-Cycle Cost Analysis
Basic Definitions
• Maintenance and Rehabilitation action (M&R action) (e.g. 60mm HMA overlay,�)
• Maintenance and Rehabilitation strategy (M&R strategy) : series of M&R actions over an analysis period.
• Maintenance and Rehabilitation alternative (M&R alternative) (EPP 30mm HMA, etc�)
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Life-Cycle Cost Analysis
Application
Hwy 53 in Lake County-11.27Km (PM0.0-PM7.00)
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Life-Cycle Cost Analysis
Project Information
• 4 lane-State Route 53 in Lake County, CA
• Climate characterized as Low Mountain (Characterized based on air temperature and precipitation)
• TI=14.2 (46.2 million ESAL’s) for a 20 year design life
• The subgrade of the pavement is SW (R=37)
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Life-Cycle Cost Analysis
Distress Mechanisms
• Rutting
• Fatigue cracks
• Environment effects in aging
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Life-Cycle Cost Analysis
CalME Predicted Rutting
160 mm HMA Type ¾”
AR-4000
375 mm AB Class 2
Subgrade SW (R=37)
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Life-Cycle Cost Analysis
CalME Predicted Cracking
Fatigue Cracking is the critical distress
160 mm HMA Type ¾”
AR-4000
375 mm AB Class 2
Subgrade SW (R=37)
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Life-Cycle Cost Analysis
Decision Trees
• Based on distress amount, material type, material thickness
• Extended Pavement Preservation (EPP): Repeated perpetually if:• down rut ≥ 5 mm or cracking ≥ 0.25 m/m2 : Use 30 mm HMA, RAC-G, or MB4
overlay (with or without milling)
• Rehabilitation (R): Repeated if: • down rut (total rut) ≥ 9 mm and rut in HMA ≥ 2 mm: Use 45 mm HMA overlay,• down rut ≥ 9 mm and rut in HMA < 2 mm: Use 75 mm HMA overlay
• Preservation-Preservation-Rehabilitation (PPR): Use if:• down rut > 5 mm or cracking >0.25 m/m2 . Use 30 mm of HMA, RAC-G or MB4
overlay (with our without milling)• down rut>5 mm and cracking > 0,25 m/m2 Use 60 mm HMA overlay.• after 2 preservation actions the next action will be treated as under rehabilitation,
followed by 2 preservation, etc.
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Life-Cycle Cost Analysis
M&R strategy EPP-HMA R-45 mm-RAC-G R-75mm-HMA
Action year 4 17 17
M&R1 30 mm HMA
Mill 30 mm RAC-
G Mill 30 mm HMA
Action year 21 25 25
M&R2
Mill
30 mm HMA 45 mm RAC-G 75mm HMA
Action year 38 32 42
M&R3
Mill
30mm HMA 45 mm RAC-G Mill 30mm HMA
Action year 55 49 59
M&R4 Mill 30mm HMA
Mill 30 mm RAC-
G Mill 30mm HMA
Action year 67 66 76
M&R5 30mm HMA
Mill 30 mm RAC-
G Mill 30mm HMA
Action year 80 0 0
M&R6 30mm HMA
M&R Strategies
Note: 25 M&R strategies have been analyzed for this project
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Life-Cycle Cost Analysis
Evaluation of M&R Strategies
TABLE 2: Summary of costs per Ln-Km for each M&R strategy
Item type Thickness (mm)
cost (1000 dollars per Ln-Km
HMA Type A 30 mm 23
HMA Type A 45 mm 41
HMA Type A 60 mm 49
HMA Type A 75 mm 50
HMA Type A 105 mm 78
RAC-G 30 mm 27
RAC-G 45 mm 41
RAC-G 60 mm 54
MB4-D 30 mm 32
MB4-D 45 mm 48
MB4-D 60 mm 64
Cold plane 30mm HMA 30 mm 9 per m2
AB Class 2 375 mm 52
HMA Type A 160 mm 120
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Life-Cycle Cost Analysis
Evaluation of M&R Strategies
TABLE 4: Annual Maintenance Cost calculation
Year
Annual Maintenance Cost ($/L-km)
MC based on Action Yr
total Lane Km
Total MC*1000
1 683
2 683 683.0 44.8 31
3 683 683.0 44.8 31
4 1366 853.8 44.8 38
5 1366 956.2 44.8 43
6 1366 1024.5 44.8 46
7 2049 1170.9 44.8 52
8 2049 1280.6 44.8 57
9 2049 1366.0 44.8 61
10 2732 1502.6 44.8 67
11 2732 1614.4 44.8 72
12 2732 1707.5 44.8 76
13 3415 1838.8 44.8 82
14 3415 1951.4 44.8 87
15 3415 2049.0 44.8 92
16 4098 2177.1 44.8 98
17 4098 2290.1 44.8 103
18 4098 2390.5 44.8 107
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Life-Cycle Cost Analysis
Evaluation of M&R Strategies
Type of Input Input Source of Input Criteria to select this input Value
Economic Variable Value of Time for Passenger Cars ($/hour) RealCost Default Value 10.46
Economic Variable Value of Time for Single Unit Trucks ($/hour) RealCost Default Value 27.83
Economic Variable Value of Time for Combination Trucks ($/hour) RealCost Default Value 27.83
Discount Rate (%) Discount Rate (%) LCCA manual [16] 3-5% range 4%
Traffic Data AADT Construction Year (total for both directions) CalME AADT CalME AADT 12275
Traffic Data Cars as Percentage of AADT (%) CalME AADT CalME AADT 95
Traffic Data Single Unit Trucks as Percentage of AADT (%) CalME AADT CalME AADT 2.5
Traffic Data Combination Trucks as Percentage of AADT (%) CalME AADT CalME AADT 2.5
Traffic Data Annual Growth Rate of Traffic (%) default default 0.0
Traffic Data Speed Limit Under Normal Operating Conditions (mph) Hwy 53 HDM 55
Traffic Data No of Lanes in Each Direction During Normal Conditions considered 2 For research purpose 2
Traffic Data Free Flow Capacity (vphpl) LCCA manual,Table6 Terrain, No. of Lanes 1950
Traffic Data Rural or Urban Hourly Traffic Distribution Hwy 53 Rural Rural
Traffic Data Queue Dissipation Capacity (vphpl) LCCA manual,Table6 Terrain, No. of Lanes 1530
Traffic Data Maximum AADT (total for both directions) LCCA manual,Table6 Terrain, No. of Lanes 48305/lane
Traffic Data Maximum Queue Length (miles) LCCA manual,Table6 Terrain, No. of Lanes 5
Construction data Agency Construction Cost ($1000) Calculated Thickness, Lane miles 1316
Construction data Agency Maintenance Cost ($1000) LCCA manual 31
Construction data Work Zone Length (miles) default LCCA manual 2
Construction data Work Zone Speed Limit (mph) LCCA manual 5 miles less than original speed 50
Construction data Work Zone Capacity (vphpl) LCCA manual, Table 6 Terrain, No. of Lanes 1360
Construction data Work Zone Duration (days) LCCA manual Eq.4 lane miles/production rate 18
Construction data Production Rate LCCA manual, Table 8 surface type, daily closure 1.5
Construction data Activity service life (yrs) see def LCCA manual 1
Traffic Data Lane closure LCCA manual Inbound and outbound first closure 0 to 6
Traffic Data Lane closure LCCA manual Inbound and outbound second closure
20 to 24
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Life-Cycle Cost Analysis
EPP vs. R Strategies
• EUAC: EPP HMA (30mm) ≈ R-75 HMA • Further analysis required to determine best strategy
EUAC Comparison
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Life-Cycle Cost Analysis
Observations
• Cracking delayed in EPP-HMA (30mm) strategy.
• Earlier cracking in R-75 HMA (at year 25) can cause moisture ingress and subgrade and base problems.
• Hence, EPP-HMA considered best economical strategy.
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Life-Cycle Cost Analysis
Summary
• The major necessity and benefit of integrating ME and
LCCA is to determine the best economical strategy for a
given pavement segment and its application times.
• For the project analyzed Extended Pavement
Preservation (EPP) was found to be the most economical
strategy. Optimal strategy may differ from project to
project.
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Life-Cycle Cost Analysis
Future Work
• Updating decision trees for the various M&R strategies in CalME. Caltrans current effort is to develop a more efficient PMS that will help in this work.
• The method presented is only for project-level optimization . Future work plans include extending its applicability to a network-level optimization.
• Incorporating LCCA module within CalME to provide a “truly” Hybrid System that will enable more efficient and speedy analysis.
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Life-Cycle Cost Analysis
Training
Fundamentals of Life Cycle Cost Analysis Live
Instructor Led Distance Learning Course
Onsite RealCost Life-Cycle Cost Analysis (LCCA)
Software Workshop
Resources
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Life-Cycle Cost Analysis
LCCA Primer
FHWA-IF-02-047
Technical Bulletin
FHWA-SA-98-079
LCCA Software
RealCost 2.5
and
User Manual
Resources
http://www.fhwa.dot.gov/infrastructure/asstmgmt/lcca.htm
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Life-Cycle Cost Analysis
Thank you
Tashia J. Clemons
FHWA HQ
Office of Asset Management
1200 New Jersey Ave SE
Washington, DC 20590
202-366-1569
http://www.fhwa.dot.gov/infrastructure/asstmgmt/lcca.htm