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NDOR Research Conference: Dr. Morcous


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Nebraska Department of Roads Conference 2012
Presented by Dr. George Morcous, University of Nebraska-Lincoln

Published in: Automotive, Technology, Business
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NDOR Research Conference: Dr. Morcous

  1. 1. Developing Deterioration Models for Nebraska Bridges George Morcous, Ph.D., P.E.Afshin Hatami, Graduate Research Assistant
  2. 2. Contents• Problem Statement• Objective• Data Analysis• Classification Parameters• Deterministic Deterioration Models• Stochastic Deterioration Models• Conclusions
  3. 3. Problem Statement• Nebraska Bridge Management Systems use national average deterioration rates, which do not represent actual performance of bridges in Nebraska.• There is a need for models that represent the true deterioration of Nebraska bridges using the condition data collected from 1998-2010.
  4. 4. Objective• Develop deterioration models for bridge decks considering the following parameters: • Average daily traffic (ADT) • Average daily truck traffic (ADTT) • Wearing surface type • Highway district • Deck protection• Two types of deterioration models were developed: • Deterministic models (i.e. deterioration curves) • Stochastic models (i.e. transition probability matrices)
  5. 5. Data Analysis
  6. 6. Data Analysis• The following records were eliminated: • Not applicable or blank condition data (culverts) • Duplicate records • Records with the same year built and year reconstructed • Records with unrecorded major maintenance actions (outliers)
  7. 7. Classification Parameters• Highway Agency District
  8. 8. Classification Parameters• Deck Structure Type• Structure Authority
  9. 9. Classification Parameters• Type of Deck Wearing Surface• Deck Protection
  10. 10. Classification Parameters• Average Daily Traffic (ADT)• Average Daily Truck Traffic (ADTT)
  11. 11. Deterministic Deterioration Models:Original Deck• Original Deck
  12. 12. Deterministic Deterioration Models:Replacement Deck• Replacement Deck
  13. 13. Deterministic Deterioration Models:Wearing Surface Type of Wearing Surface Type of Wearing Surface Age of Deck (Years)
  14. 14. Deterministic Deterioration Models:Wearing Surface• Deck Overlays: – Silica Fume (70 Data) – Latex Concrete (27 Data) – Low Slump Concrete (338 Data) Age of Overlay (Years) Duration to Overlay (Years)
  15. 15. Deterministic Deterioration Model:Wearing Surface• Low Slump Concrete
  16. 16. Deterministic Deterioration Models:Deck• Average Daily Truck Traffic (ADTT) and Average Daily Traffic (ADT)
  17. 17. Deterministic Deterioration Models:Deck
  18. 18. Deterministic Deterioration Models:Deck• Highway Agency District
  19. 19. Stochastic DeteriorationModels• Markov-chain models predict the transition probability from one condition state to another given the transition period• Transition probabilities were determined using the percentage prediction method
  20. 20. Stochastic DeteriorationModels: Deck
  21. 21. Stochastic DeteriorationModels: DeckLow Environment Moderate Environment
  22. 22. Stochastic DeteriorationModels: DeckSevere Environment Time (years)
  23. 23. Stochastic DeteriorationModels: Deck Protection
  24. 24. Stochastic DeteriorationModels: Deck Protection
  25. 25. Stochastic DeteriorationModels: Deck Protection
  26. 26. Conclusions• Deterioration Rate for original concrete decks in the state of Nebraska is slightly lower than the national average.• The higher the traffic volume (ADT and ADTT), the higher the deterioration rate of concrete bridge decks.• Service life for bridge decks with epoxy coated reinforcement and black rebar at fair condition (condition 5) are approximately 68 and 40 years, respectively.• Bridge decks in state bridges in Highway District 2 have higher deterioration rates than those in districts 1, 3 and 4, which is higher than those in districts 5, 7 and 8.• Deterioration rate for low-slump concrete overlay is higher than that of original concrete deck.
  27. 27. CREDITS Dr. George Morcous, Ph.D., P.E.Afshin Hatami, Graduate Research Assistant University of Nebraska-Lincoln Slide design © 2009, Mid-America Transportation Center. All rights reserved.