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State-SpecificOnline self-study

South Carolina Bridge Program Primer: BIGD and LRGD Roles

1 PDH · about 60 minutes · Course no. BR-X02 · 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.

South Carolina's bridge program runs on two SCDOT guidance documents that every inspector, load rater and consultant working for the department needs to know: the Bridge Inspection Guidance Document (BIGD), published by the Bridge Maintenance Office (BMO), and the Load Rating Guidance Document (LRGD). This one-hour primer explains what each document does, who the key players are, how a finding in the field becomes a load rating request, how a load rating becomes a posting or a Critical Finding, and which South Carolina-specific numbers (time limits, triggers and thresholds) are easy to get wrong. It is based on the May 2026 BIGD and the August 2019 LRGD as obtained for this course, read alongside the federal National Bridge Inspection Standards (23 CFR 650 Subpart C). SCDOT updates these documents; always confirm the current edition before relying on any number here.

⬇ Download study guide (PDF)

Learning objectives

  • Describe the roles of the SCDOT BIGD and LRGD
  • Explain the inspector-to-rater handoff
  • Recognize SCDOT-specific accuracy locks
  • Know where to verify current guidance

Outline

  1. Two documents, one program
  2. Who does what in the BIGD
  3. Inspector qualifications in South Carolina
  4. Inspection types and intervals
  5. The desk review: reading the load rating before the field
  6. When the BITL must request a load rating
  7. Condition State 4 and Table 31
  8. Repair recommendations and priority flags
  9. Critical Findings, the South Carolina way
  10. Closure, addressed and resolved
  11. Inside the LRGD: who may rate and how it is checked
  12. LRGD methods, data and policy points
  13. Posting under the LRGD
  14. Quality control, quality assurance and FHWA oversight
  15. Accuracy locks and verifying current guidance
  16. Bridge design in South Carolina: SCDOT standards
  17. Bridge repair in South Carolina
  18. Open the course (23 screens, 2 knowledge checks)
  19. Final quiz — 10 questions, 70% to pass

References

  1. SCDOT, Bridge Inspection Guidance Document (BIGD)
  2. SCDOT, Load Rating Guidance Document, 2019
  3. 23 CFR Part 650, Subpart C — National Bridge Inspection Standards (final rule published May 6, 2022)
  4. SCDOT Bridge Maintenance Office, Bridge Inspection Guidance Document (BIGD), May 2026 edition as reviewed
  5. SCDOT, Load Rating Guidance Document (LRGD), August 2019 edition as reviewed
  6. SCDOT Bridge Design Manual and Bridge Design Memoranda (scdot.org, reviewed October 2026)
  7. SCDOT Seismic Design Specifications for Highway Bridges