MDOT defines structurally deficient vs. functionally obsolete br - WDAM - TV 7 - News, Weather and Sports

MDOT defines structurally deficient vs. functionally obsolete bridges

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According to The Mississippi Department of Transportation, a bridge on Ellisville Boulevard, which was built in 1929, is considered to be structurally deficient. Thousands of times a day, trucks, cars, SUVs and 18-wheelers cross.

"We will not allow a public bridge to remain open that is not safe," said Melinda McGrath, P.E., MDOT Executive Director.

According to MDOT, 30 bridges are classified as structurally deficient. 139 are functionally obsolete. Structurally deficient means parts of a bridge that require monitoring or repair, but does not indicate the bridge is unsafe or likely to collapse. 

Functionally obsolete means the design is outdated such as having narrow shoulders and low clearance underneath. 

"As time has gone on, and there's more vehicles on the road, and there's larger vehicles on the road, the geometry features have changed."

The American Road and Transportation Builders Association Analysis ranks Mississippi 10th nationally in the number of structurally deficient bridges and 14th in percentage of deficient bridges. 

"$4 billion would be needed to correct all of the structurally deficient bridges in our state," McGrath added.

If the money isn't available for repairs, it will cause 18-wheelers and school buses to be detoured first, McGrath added.

"If we cannot either replace the bridge, or make some sort of a repair like driving a new piling or reinforcing the cap that holds up the deck, then the bridge will be closed," McGrath said.