What is the purpose of the NBIS rating of substructure?

• A. Evaluate the condition of piers, abutments, and foundations to ensure safety.
• B. Evaluate deck wear.
• C. Assess aesthetics.
• D. Determine traffic capacity.

Answer: (A)

The thing being tested is understanding what the substructure rating is for: it measures the condition of the parts of the bridge that support the deck and transfer loads to the ground—piers, abutments, and foundations. By looking for deterioration, movement, settlement, or instability in these elements, inspectors gauge whether the structure remains safe and determine if repairs or strengthening are needed. This focuses on structural safety of the load-bearing components, not on the deck surface, aesthetics, or how much traffic load the bridge can carry, which are addressed by other aspects of bridge assessment.