Kansas Department of Transportation "...to provide a statewide transportation system to meet the needs of Kansas."

 What are Deficient or Obsolete Bridges?

We will close a bridge if we have any concerns about the safety of the traveling public.

Structurally Deficient
A bridge that is inadequate to carry today’s legal loads, whether by obsolete design standards, structural deterioration or waterway inadequacy. It is possible to have a structurally deficient bridge that is safe to use, particularly when the rating is due to the design type. For example, if a bridge was designed in the 1920s when a 5-ton load was considered a big load, it could still be on the state highway system and be in good condition. Since it was built before today’s heavier loads, we would post a weight limit on the bridge. KDOT’s standards of what is structurally deficient exceed the federal standards.

Of the nearly 5,000 bridges on the state highway system, 104 (about 2 percent) are structurally deficient (July 2007).

To determine if a bridge is structurally deficient, the engineers’ evaluation includes the bridge deck, superstructure, substructure, culverts and retaining walls, and overall structural condition.

We will watch structurally deficient bridges more closely, recognizing that we may need to repair, rehabilitate, or replace them at some time in the future.

Functionally Obsolete
A bridge not built to today’s engineering criteria that is inadequate to accommodate traffic because it is narrow, the clearance beneath it is inadequate, the approaching roadway alignment is deficient, its structural condition, or waterway adequacy. Most functionally obsolete bridges are narrower than today’s newer bridges.

Of the nearly 5,000 bridges on the state highway system, 437 (about 8.75 percent) are functionally obsolete (July 2007).

To determine if a bridge is functionally obsolete, the engineers’ evaluation includes the deck geometry (width and alignment), clearances beneath the bridge, and the alignment of the approach roadway.

Last updated : July 15, 2013