BLOUNTVILLE — It could take $8.4 million or more to turn the steel truss bridge on Highway 75 near Boone Dam into a walking and biking bridge, according to a letter to Sullivan County Mayor Steve Godsey from Tennessee Transportation Commissioner Gerald F. Nicely.
If the bridge is linked to a trail system, however, it should qualify as eligible for certain grant funds, according to the letter, dated April 3 and distributed Monday to Sullivan County commissioners. But the letter warns that grant process is highly competitive.
County officials were incredulous at the cost estimates.
“At this time, the (Tennessee Department of Transportation) is requesting formal response from the county regarding interest in leaving the bridge in its current location and acceptance of the liability and maintenance of the structure,” Nicely wrote near the end of the letter.
Last month the Sullivan County Commission voted against asking the state to dismantle — rather than demolish — the circa 1936 bridge, which is scheduled for replacement with a new structure just upstream.
This month, the County Commission’s agenda included a resolution on first reading to ask the state to leave the bridge where it is so it can become a pedestrian bridge when its replacement opens to traffic. County officials have said the idea of making it a pedestrian bridge originated with TDOT, which has performed similar conversions on bridges elsewhere in the state — most notably, perhaps, in downtown Chattanooga.
Closer to home, a bridge on Netherland Inn Road in Kingsport is to be converted for pedestrian use when a new bridge opens.
According to Nicely’s letter to Godsey:
•“If the existing (Highway 75) bridge were to remain at its existing location as a pedestrian bridge, it is estimated that a full rehabilitation to convert the bridge, including fencing along each side for safety reasons, would be roughly $6 million,” Nicely wrote. “This figure would include a new paint job (which should last roughly 20 to 30 years if supplemented with occasional spot paint), all steel repairs and strengthening, and the repair of a small erosion issue at the Abutment One end of the bridge.
“Assuming that work is done, an annualized cost over the next 10 to 15 years for maintenance would be approximately $10,000 or less which would include items such as greasing the bearings and keeping them protected and an occasional spot paint or curb repair. After that the annualized maintenance cost may rise somewhat.”
•The new bridge’s substructures would ideally align with those of the existing truss bridge — but that would require a redesign of what is now planned to be a concrete structure to another steel structure, carrying a potential price tag of another $2.4 million.
•Another option would be to leave the bridge as a “visual ruin.” It would not be usable as a bridge — for vehicles or pedestrians — but the trusses would be retained “in the event someone later wanted to use them” and “it would be possible for citizens to view it as a local structure, even though they could not walk across it.” Under this option, approach spans and decking would be removed, leaving the span inaccessible. Estimated cost: $250,000.
•TDOT estimates dismantling the 760-foot circa 1936 bridge and moving it to the county seat would cost “at minimum, $1 million to $1.5 million.”
•The estimated cost to demolish and remove the structure is about $300,000.
The resolution to ask the state to save the steel truss bridge on Highway 75 for use as a pedestrian bridge could come for a commission vote on May 19.