After working diligently for over a year on envelope vehicle configurations of 5-13 axles, SC&RA unveils the Uniform Permit Transport 2021 proposal as a basis for discussion with individual states, as well as our four regions. Uniform Permit Transport 2021 represents our goal of 100% compliance across the country by the year 2021, as we advocate widespread acceptance of more comprehensive and representative vehicle models issued under routine or auto issued permits. This panel discussion will cover the merits of the proposal. Representatives of SC&RA will also share a plan of action to fight for uniformity to save members time and money. Moderator: Doug Miller, VP, Burkhalter Speakers: Todd Gibson, Bridge Evaluation/Hauling Permit Engineer, West Virginia DOT David Koenig, Bridge Management Engineer, MoDOT-Bridge Division Phillip Litchfield, Senior Bridge Rating Engineer, Illinois Department of Transportation

1. Permit Evaluations from a
Bridge Engineering Perspective

2. WVDOT Mission Statement
The West Virginia Department of Transportation’s
mission is to responsibly provide a safe, efficient and
reliable transportation system that supports economic
opportunity and quality of life.

3. WVDOT Essential Services
• Safety and protection
• Transportation services
• Community and economic development
• Revenue generation
• Information and education
https://transportation.wv.gov/secretary/Pages/blah.aspx

4. WVDOT Challenge
Economic
Development
Safety and
Protection

5. Oversize and Overweight Permits
• Safety
• Traveling Public
• Permitted Move
• Asset Preservation
• Bridges
• Roadways

6. Bridge Rating
• Calculate member capacities
• Determine live load demand
• Verify bridge capacity is greater than live load demand

7. AASHTO Guidance
• AASHTO Manual for Bridge Evaluation, 2nd Edition
• AASHTO LRFD Bridge Design Specifications, 8th Edition
• AASHTO Standard Specifications for Highway Bridge, 17th Edition

8. Bridge Member Ratings
• Load and Resistance Factor Design
• RF=
𝐶−γ 𝐷𝐶
𝐷𝐶 −γ 𝐷𝑊
(𝐷𝑊)±γ 𝑃
(𝑃)
γ 𝐿𝐿
(𝐿𝐿+𝐼𝑀)
• Load Factor Design
• RF=
𝐶−𝐴1 𝐷
𝐴2 𝐿(1+𝐼)

9. Bridge Member Ratings
• Load and Resistance Factor Design
• RF=
𝐶−γ 𝐷𝐶
( )𝐷𝐶 −γ 𝐷𝑊
(𝐷𝑊)±γ 𝑃
(𝑃)
γ 𝐿𝐿
(𝐿𝐿+𝐼𝑀)
• Load Factor Design
• RF=
𝐶−𝐴1 𝐷
𝐴2 𝐿(1+𝐼)
Available Capacity

10. Bridge Member Ratings
• Load and Resistance Factor Design
• RF=
𝐶−γ 𝐷𝐶
𝐷𝐶 −γ 𝐷𝑊
(𝐷𝑊)±γ 𝑃
(𝑃)
γ 𝐿𝐿
(𝐿𝐿+𝐼𝑀)
• Load Factor Design
• RF=
𝐶−𝐴1 𝐷
𝐴2 𝐿(1+𝐼)
Live Load Demand

11. Live Load Demand
• Load and Resistance Factor Design
• γ 𝐿𝐿(𝐿𝐿 + 𝐼𝑀)
• 1.1 (Escorted with no other vehicles on
the bridge)
• 1.2 (Mix with traffic)
• Load Factor Design
• 𝐴2 𝐿(1 + 𝐼)
• 1.3
Load Modifier

12. Live Load Demand
• Load and Resistance Factor Design
• γ 𝐿𝐿(𝐿𝐿 + 𝐼𝑀)
• Load Factor Design
• 𝐴2 𝐿(1 + 𝐼)
Impact Factor

13. Impact Factor
• 10% - Smooth riding surface at approaches, bridge
deck, and expansion joints
• 20% - Minor surface deviations of depressions
• Full impact
• 30% Load Factor Design
• 33% Load and Resistance Factor Design
• Impact factor may be eliminated for slow moving
(<10 MPH) permitted vehicles
Impact values may be reduced if speed control is ensured.

14. Live Load Demand
• Load and Resistance Factor Design
• γ 𝐿𝐿(𝐿𝐿 + 𝐼𝑀)
• Load Factor Design
• 𝐴2 𝐿(1 + 𝐼)
Live Load Effect

15. Live Load Effects

16. Live Load Effects
• There are two methods to determine the live load effects on
bridge members
• Approximate Methods
• Refined Analysis

17. Approximate Methods
• Follow equations set forth in the
Manual for Bridge Evaluation
• Can be conservative
• Based on 6’ axle gage

18. Refined Analysis
• Solves complex problems by subdividing them into smaller
problems
• Determines load transfer based on the actual bridge
geometry and material properties
• Ability to evaluate complex structures with non-standard
loads

19. Refined Analysis

20. $64,000 Question
• How can two similar bridges rate differently?
• Because no two bridges are exactly alike
• Condition
• Material properties
• Geometry Changes
• Etc.

21. Condition

22. Condition
Bridge appears to be in
good condition
No visible corrosion

23. Condition

24. Condition

25. Condition

26. Condition

27. Questions
Todd Gibson, PE
Hauling Permit/Bridge Evaluation Engineer
Todd.d.Gibson@wv.gov
(304) 558-9478