How does NBIS define 'structurally deficient' and 'functionally obsolete'?

How does NBIS define 'structurally deficient' and 'functionally obsolete'?

• A. Structurally deficient indicates cosmetic issues only; functionally obsolete refers to outdated signage.
• B. Structurally deficient indicates significant structural issues affecting load capacity; functionally obsolete refers to geometry or hydraulics that no longer meet current needs.
• C. Structurally deficient means the bridge is closed; functionally obsolete means it has insufficient lighting.
• D. Structurally deficient and functionally obsolete are interchangeable terms.

Answer: (B)

NBIS uses two distinct concepts: one about the structure’s capacity to carry loads, and one about meeting modern design standards. Structurally deficient means there are significant structural problems with the bridge’s load‑carrying elements—such as the deck, superstructure, or substructure—that can limit its ability to safely carry loads. Functionally obsolete means the bridge’s geometry or hydraulics don’t meet current design standards—things like lane width, vertical clearance, or flood flow capacity. So the best description is that structurally deficient points to serious structural issues affecting load capacity, while functionally obsolete refers to outdated geometry or hydraulics that no longer meet needs. A bridge can be structurally deficient without being functionally obsolete, and vice versa; cosmetic issues, signage, or lighting aren’t the defining factors.

NBIS uses two distinct concepts: one about the structure’s capacity to carry loads, and one about meeting modern design standards. Structurally deficient means there are significant structural problems with the bridge’s load‑carrying elements—such as the deck, superstructure, or substructure—that can limit its ability to safely carry loads. Functionally obsolete means the bridge’s geometry or hydraulics don’t meet current design standards—things like lane width, vertical clearance, or flood flow capacity. So the best description is that structurally deficient points to serious structural issues affecting load capacity, while functionally obsolete refers to outdated geometry or hydraulics that no longer meet needs. A bridge can be structurally deficient without being functionally obsolete, and vice versa; cosmetic issues, signage, or lighting aren’t the defining factors.