Skip Navigation
MI.gov
MDOT - Michigan Department of Transportation Michigan Department of Transportation
Michigan Department of Transportation
Email this Page
Share this Link on Facebook
Tweet this page on Twitter!

Structurally Deficient

The Federal Highway Administration has established definition for Structurally Deficient. Structural deficiency ratings are based on the National Bridge Inventory ratings scale.

Structurally Deficient (SD) Status - A highway bridge is classified as structurally deficient if the deck, superstructure, substructure, or culvert is rated in "poor" condition (0 to 4 on the NBI rating scale). A bridge can also be classified as structurally deficient if its load carrying capacity is significantly below current design standards or if a waterway below frequently overtops the bridge during floods.





Copyright 2015 State of Michigan