NASHVILLE, Tenn. (WKRN) — Less than a month ago, the Tennessee Department of Transportation reopened the Hernando DeSoto Bridge in Memphis after it was deemed unsafe due to a crack in its structure.
According to the National Bridge Inventory, Tennessee has nearly 900 structurally deficient bridges across the state.
Every day, an estimated 178,050 rely on the I-24 bridge over Mill Creek in Davidson County. According to National Bridge Inventory, it’s the most structurally deficient bridge in the state. Three other Davidson County bridges and one Williamson County bridge also rank in the top 10.
Will Reid, TDOT’s Assistant Chief Engineer over Program Delivery, explained what makes a bridge structurally deficient.
“Your main elements of the bridge, [the] substructure, superstructure, and really the deck. So if one of those is in poor condition, the bridge is deemed to be structurally deficient,” Reid explained.
Even if a bridge is considered structurally deficient, Reid said that doesn’t necessarily mean it’s unsafe for travel.
“So just because a bridge is structurally deficient, that means that some portion of the bridge is in need of some kind of repair, but it is safe to travel on, otherwise it would be close,” Reid said.
TDOT is responsible for inspecting 20,000 highway bridges across the state. Bridges must be inspected at least every two years. Reid said the I-40 bridge in Memphis was actually an example of their inspection protocol working.
“This is an example of why we do inspections on a regular interval. In this case, the inspection caught what it should have and we were able to make a call very quickly to shut that bridge down,” Reid said.
TDOT said completely shutting down a bridge is rare, although they will shut them down to check for damage after wrecks or if a bridge is hit by an oversized load.
After the Memphis incident, they also doubled down on their commitment to bridge inspections.
“It’s very important to make sure we have adequate credentials and people that understand what they’re looking at and that we do that on a very regular interval and that those inspections are all-encompassing,” Reid said.
TDOT spends an average of $50 million each year on bridge repairs, in addition to roughly $10 million that goes towards replacing bridges. When it comes to allocating resources, Reid said TDOT prioritizes spending on maintaining and repairing the bridges Tennessee already has before trying to build new ones.