Structurally Deficient Bridges

Structurally Deficient Bridges on the Maryland State Highway System

As of March 15, 2018

The structurally deficient rating is an early warning sign for engineers to prioritize funding and to rehabilitate or to begin the process to replace the bridge.

The rating applies to three main elements of a bridge:

  1. the deck (riding surface)
  2. the superstructure (main supporting element of the deck, usually beams, girders, and trusses)
  3. the substructure (supports to hold up the superstructure and deck, usually abutments and piers)

These elements are rated on a scale from zero (closed to traffic) to nine (relatively new). If any of the three elements is rated as a four or less, the bridge is categorized as structurally deficient by federal standards. This does not mean that the bridge is unsafe.

If a bridge becomes unsafe, it will be closed.

The summary below is taken from the annual submission (PDF, 52kb) to FHWA made in March 2018. This submission reports that there are 2569 bridges on the Maryland State Highway System, of which 67, or about 3%, are classified as structurally deficient. The number of structurally deficient bridges decreased from 143 in 2006 to 62 in 2018.

Summary for 2018
Number of poor rated bridges on March 15, 201862
Number of poor rated bridges addressed in 201818
Number of bridges which became poor rated in 20188
Total number of structurally deficient bridges on March 15, 2019