LoadPath PDH — PE/NICET supplemental PDH (not FHWA/NBIS refresher training).

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TimberOnline self-study

Timber Bridge Inspection and Decay

1 PDH · about 60 minutes · Course no. BR-T01 · Instructor: Michael Craig, PE

About the instructor

Michael Craig, PE is Senior Vice President and Southeast Director at Strinteg Corporation, leading bridge inspection and structural engineering across eight states and Puerto Rico. In 27+ years he has inspected over 4,000 structures and completed 3,000+ load ratings and 160+ load tests. He has managed repair and preservation design for complex bridges, including cable-stayed bridges. He holds PE licenses in twelve states, DC and Puerto Rico, SPRAT Level 1, and FAA Part 107 credentials.

Timber bridges are still common on local roads, forest roads and in parks, and decay remains their main cause of deterioration. This course is built on Chapter 13, Bridge Inspection for Decay and Other Deterioration (Ritter and Morrell), and Chapter 14, Maintenance and Rehabilitation of Timber Bridges, of Timber Bridges: Design, Construction, Inspection, and Maintenance (Ritter, USDA Forest Service EM 7700-8, 1990). It covers the organisms that attack wood, the tools used to find exterior and interior deterioration, inspection sequence and reporting, preservative and in-place treatment issues, and how decay findings are turned into residual section for rating. The source dates from 1990: tool technology has advanced and the regulatory status of some preservatives named in it has changed, so treat chemical names as historical and check current labels and agency rules. Worked numbers are labeled illustrative.

⬇ Download study guide (PDF)

Learning objectives

  • Describe decay fungi and insects
  • Use sounding, drilling and coring
  • Recognize preservative treatment issues
  • Rate timber components

Outline

  1. Why timber inspection is different
  2. What wood-destroying organisms need
  3. Fungi: mold, stain and the three decays
  4. Insects: termites, ants, beetles and bees
  5. Marine borers
  6. Physical agents of deterioration
  7. Detecting exterior deterioration
  8. Detecting interior deterioration
  9. Where decay starts: high-hazard locations
  10. Inspection procedure: from the office to the deck
  11. Reports and records
  12. Preservative treatment issues and in-place treatment
  13. From findings to rating: strength loss and residual section
  14. Field checklist
  15. Open the course (20 screens, 2 knowledge checks)
  16. Final quiz — 10 questions, 70% to pass

References

  1. Ritter, M.A., Timber Bridges: Design, Construction, Inspection, and Maintenance, USDA Forest Service EM 7700-8, 1990
  2. USDA Forest Products Laboratory, Wood Handbook: Wood as an Engineering Material, FPL-GTR-282, 2021
  3. FHWA, Bridge Inspector's Reference Manual (BIRM), FHWA-NHI-12-049, 2012 (as revised)
  4. Ritter, M.A., and Morrell, J.J., Chapter 13, Bridge Inspection for Decay and Other Deterioration, in Timber Bridges: Design, Construction, Inspection, and Maintenance, EM 7700-8, USDA Forest Service, 1990.
  5. Ritter, M.A., Chapter 14, Maintenance and Rehabilitation of Timber Bridges, in EM 7700-8, USDA Forest Service, 1990.