Two local bridges that carry at least 10,000 vehicles a day are listed as “functionally obsolete” by the National Bridge Inventory, yet highway officials have no plans to repair those bridges.

Two local bridges that carry at least 10,000 vehicles a day are listed as “functionally obsolete” by the National Bridge Inventory, yet highway officials have no plans to repair those bridges.
There are two ratings on the National Bridge Inventory that notifies officials of bridges to watch.
One rating, “structurally deficient,” marks the bridge as closed or restricted to certain vehicles because of deterioration. These bridges have limits for speed and weight.
The other rating, “functionally obsolete,” signifies a bridge with older design features. These bridges are not unsafe, but were not meant to carry certain traffic and weights found in modern vehicles.
One bridge in Bourbon County and one in Crawford County received the latter rating. Both bridges are along U.S. 69 Highway.
The Bourbon County bridge is the bridge where U.S. 69 crosses over Wall Street in Fort Scott. However, despite a “functionally obsolete” rating, the bridge also received a rating of 94 on an inspection from December 2005.
Priscilla Peterson, Kansas Department of Transportation public information manager, said the bridge was nothing about which to be concerned.
“The bridge is in good shape. It has an older design features, which prompted the rating,” Peterson said. “Eastbound on Wall Street, there is a height restriction. That’s what earns the rating. Otherwise, it’s in good shape.”
Peterson added that there are no plans to make any changes to the bridge.
The other bridge, in Crawford County, does not have as good a rating, but may also be in good shape, said George Dockery, KDOT area engineer.
Along U.S. 69, just south of the Garden of Memories cemetery is a reinforced concrete box culvert with three cells. This bridge is listed as functionally obsolete because of when and how it was originally built.
“It’s very small. It was built in 1952,” Dockery said. “The bridge itself is actually a very good rating. In 1952, the design criteria had to carry 20 tons, and today that criteria is much higher. Those cars back then, it was a factor of safety. The designers designed it to carry a 20-ton load, but it could carry four times that.”
Dockery said the reason it could carry four times that much load is because the bridge was over-designed when it was built in such a way that it could be much sturdier than its original purpose required. However, when put into the federal formula, Dockery said the formula asks for the criteria for which the bridge was originally built, not what it can carry.
“Because it’s such a small structure, and it was built for 20 tons but also has a rating to carry four times that, it can handle modern semis,” Dockery said. “Those can weigh up to 80 tons, but they never get all their axles on such a small structure, so all 80 tons are never on it at any time.
“We’ve also done inspections yearly on that bridge, but there are no signs of cracking or anything that shows it is wearing down.”

Andrew Nash can be reached at andrew.nash@morningsun.net or by calling 231-2600 ext. 132.