Use of Full Depth Shoulders on Wisconsin Highways

Steve Krebs, Bob Arndorfer, and Jed Peters – DTSD-Bureau of Technical Services

April 29, 2013

Literature Review Current Design Practices Pavement Performance Observations Full Depth Shoulder (FDS) Construction and Cost

Considerations FDS Life Cycle and Benefit-Cost Analyses Benefits Recommendations/Implementation Costs

Overview of presentation

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Design Standards 1990 FHWA Advisory Mechanistic-Empirical Pavement Design Guide Wisconsin Highway Research Program (WHRP) Report

FDS Benefits Construction Maintenance of Traffic Incidents/Events Emergency Evacuations

Other State Practices

Literature Review

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Geometry Thickness

Current WisDOT Design Practices

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Pavement Distress NE Region SE Region NW Region

Preventative Measures

Pavement Performance Observations

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10 Projects Analyzed 8 Concrete Mainline 2 HMA Mainline

As-built and Estimated FDS Costs

FDS Construction and Cost Considerations - Overview

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FDS Construction and Cost Considerations – Cross-Sectional Assumptions

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FDS Construction and Cost Considerations – Cross-Sectional Assumptions

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Construction Cost Calculations

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Concrete Mainline Projects As-built average (avg) cost: $182,920/mile FDS HMA avg cost: $346,430/mile FDS concrete avg cost: $265,000/mile

HMA Mainline Projects As-built average (avg) cost: $123,320/mile FDS HMA avg cost: $171,600/mile

Construction Cost Summary

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Costs/Impacts not Considered Maintenance Schedules

Conventional FDS

Time Value of Money

Life Cycle Cost Analysis (LCCA) - Overview

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Concrete Mainline Projects As-built avg net present value (NPV) life-cycle 50 year cost:

$276,720/mile FDS HMA avg NPV life-cycle 50 year cost : $428,310/mile FDS concrete avg NPV life-cycle 50 year cost :

$345,140/mile

HMA Mainline Projects As-built avg NPV life-cycle 50 year cost : $198,050/mile FDS HMA avg NPV life-cycle 50 year cost : $243,210/mile

* NPV calculated with 3.5% discount rate

LCCA– Summary

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Split Axis LCCA Cash Flow

LCCA vs BCA Dissimilar Alternative: User Delay

Conventional Shoulder User Delay NPV = $146,830/mile

Benefit Cost Analysis (BCA)

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Concrete Mainline Projects As-built avg NPV life-cycle 50 year cost: $423,550/mile FDS HMA avg NPV life-cycle 50 year cost : $428,310/mile FDS concrete avg NPV life-cycle 50 year cost :

$345,140/mile

HMA Mainline Projects As-built avg NPV life-cycle 50 year cost : $344,880/mile FDS HMA avg NPV life-cycle 50 year cost : $243,210/mile

* NPV calculated with 3.5% discount rate

BCA– Summary

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Non-Denominated IH-43 IH-94

Denominated IH-39 – Shoulder Replacement IH-94 – Shoulder Widening USH 41 – Shoulder Widening

Additional Identified Benefits

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Estimated As-Built Construction Cost/Mile $151,570/mile (1984 Dollars) $337,550/mile (2012 Dollars)

Estimated 10” FDS Construction Cost/Mile $190,840/mile (1984 Dollars) $425,010/mile (2012 Dollars)

LCCA Costs As-built NPV = $456,110/mile FDS NPV = $535,720/mile

2012 Project - 8” Shoulders Let Cost/Mile $333,850/mile

IH-39 Cost Summary

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Adjusted LCCA Costs As-built NPV = $515,000/mile FDS NPV = $467,540/mile

IH-39 Cost Summary Cont…

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USH 41 Existing Cross Section

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USH 41 As-Designed/Built Cross Section

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USH 41 Theoretical Widening with Incorporation of FDS

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Actual Widening Cost = $7.28 Million Estimated Widening Cost with Incorporation of

FDS = $5.17 Million Cost Savings of $272,000/mile

USH 41 Cost Summary

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Actual Widening Cost = $3.99 Million Estimated Widening Cost with Incorporation of

FDS = $3.07 Million Cost Savings of $178,000/mile

IH-94 Cost Summary

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Selective Application of FDS High Volume Arterial Corridors Mass Evacuation Routes

Incorporate FDS (Existing and Future) into Emergency Planning

Recommendations

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Volumes Estimated For Highest Direction in 30th Highest Hour in 2013

Average Outside FDS Cost: $248,575/mile Average Inside FDS Cost: $165,480/mile

HMA Conventional Shoulder to Concrete FDS Outside shoulder only: additional $108,100/mile Both shoulders: additional $164,000/mile

Concrete Conventional Shoulder to Concrete FDS Outside shoulder only: savings of $28,800/mile Both shoulders: savings of $41,500/mile

Cost to Implement

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Southeast N-S and Zoo Freeways

Southwest IH-39 Corridor Reconstruction

Northeast USH 41 (Winnebago and Brown Counties)

Region Self Implementation

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Questions?

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