Two Warren County bridges – one rated structurally deficient and another rated functionally obsolete by the Kentucky Transportation Cabinet – are set to be replaced over the next two years through the 2012 State Highway plan.
The projects collectively are expected to cost about $6.51 million.
Of 103 bridges and other structures inspected by the Kentucky Transportation Cabinet District 3 in Warren County over a two-year period, 15 were listed as functionally obsolete and two were listed as structurally deficient, according to records provided by the cabinet. Three bridges within the county required a fracture critical inspection.
A September analysis by The Associated Press of 607,605 bridges on the federal National Bridge Inventory showed 65,605 were listed as structurally deficient.
The district inspects bridges on a two-year cycle, unless they are posted with some kind of limit, such as weight, Chief District Engineer Greg Meredith said. Posted structures are usually inspected every year.
Warren County has two posted structures, according to Darren Stewart, section supervisor for structures at District 3. One is on Bogle Road over the R. J. Corman railroad and one is on Old Richardsville Road over Barren River.
A structure is classified as structurally deficient if any of the main load carrying elements are of poor quality.
A functionally obsolete structure is one with clearance issues for current traffic, such as vertical or horizontal clearance, Stewart said. A bridge also qualifies as functionally obsolete if the volume of traffic using the bridge exceeds the volume for which it was designed.
Bridges that require fracture critical inspections have an element within the bridge that is in tension to the point that, if that element were to fail, part or all of the structure could be lost.
“During fracture critical inspections, we’re mandated to get within arm’s length of any fracture critical details,” Stewart said.
But just because a structure is fracture critical, it doesn’t mean that it is set to be replaced. If a structure has a sufficiency rating of 50 or below, it could be considered for a replacement project.
A sufficiency rating is derived from a complex formula that takes in multiple factors of a structure’s health, including if a bridge is rated as structurally deficient and functionally obsolete, Meredith said.
Fracture critical structures are given a close inspection every two years, Meredith said. A truck called a snooper, similar to a bucket truck, is often used so inspectors can get closer to elements beneath a structure.
“That’s how we keep a really good eye on those,” he said.
Stewart said Warren County bridges generally are in good shape.
Stewart or another inspector must inspect bridges and other structures, such as culverts, that carry traffic or go over public traffic with a span of more than 20 feet.
All primary load-carry elements of a structure have to be inspected and deterioration documented during an inspection.
Structures in Warren County that required fracture critical inspections during a two-year period include one on Old Richardsville Road two-tenths of a mile west of the junction with Ky. 185, one on Ky. 185 2.23 miles north of the junction with U.S. 68/80 and one on Ky. 101 on the Allen/Warren County line, according to records from the transportation cabinet.
There are two bridges currently up for replacement on Kentucky’s 2012 Highway Plan.
“Kentucky has been pretty proactive throughout the years with bridge replacement, bridge maintenance,” Meredith said.
District 3, which includes Allen, Barren, Butler, Edmonson, Logan, Metcalfe, Monroe, Simpson, Todd and Warren counties, has fewer bridges than many districts as well as smaller bridges than many others.
The bridge replacement project that is expected to be constructed the earliest is on Bogle Road over R. J. Corman Railroad near South Union and the Logan County line, Meredith said.
That project is set to go into construction in 2014, according to the highway plan. The total project cost listed on the plan is $800,000.
“It’s sufficiency rating is really low – it’s like 16.5 – but a lot of things go into that rating,” Meredith said.
The bridge was built in 1900, according to transportation cabinet records.
Decisions about which bridge projects need to be placed on the highway plan are based on inspections and the recommendations of inspectors, he said.
“Actually their recommendations and their evaluations are what really populate ... which bridges need to be replaced,” Meredith said.
The Bogle Road bridge is also one of two structures inspected in the last two years with a structurally deficient rating in the county, according to records provided by the transportation cabinet.
The other, built in 1920, is on Old Richardsville Road about two-tenths of a mile west of the junction with Ky. 185. It also requires a fracture critical inspection, according to transportation cabinet records.
Another bridge set for replacement is on Ky. 234/Cemetery Road over Drakes Creek. That bridge is set to be replaced with a widened bridge with three lanes instead of two, Meredith said.
The design on that project was recently started.
Construction is not set to begin until 2017, according to the highway plan. The total cost of the project is $5,710,000.
The Ky. 234 bridge was built in 1963 and is one of 15 structures inspected in Warren County during a two-year period to be rated as functionally obsolete, according to transportation cabinet records.