PYMATUNING TOWNSHIP — The Mercer County map on Brad Elder’s office wall has 247 pins — each one representing a county-owned bridge.
“It’s quite an inventory that we’ve got,” said Elder, the county’s bridge engineer.
That inventory is turning into quite an expense. Mercer County Commissioners have estimated the county will have to pay about $30 million over the next 10 years to replace deteriorating spans.
That doesn’t count projects — like the Kelly Road bridges in Sharpsville and Hermitage, or the Ohl Street Bridge in Greenville — already funded under the the PennDOT Transportation Improvement Plan, or TIP.
PennDOT provides bridge maintenance and replacement money to Mercer County through three programs funded by the state’s gasoline tax, and also through Pennsylvania’s hydraulic fracturing, or fracking, gas well fees. The county typically receives between $600,000 and $900,000 a year from those three revenue streams.
That includes the December 2018 round of liquid fuels payments from the state to all 67 of Pennsylvania’s counties. The figures, announced this month, included $173,045.72 for Mercer County.
PennDOT sets the allotments based on the square footage of bridge deck each county controls and how much gasoline tax the state collected during the previous six-month period.
“The percentage is always the same,” Elder said. “But the size of the pot changes.”
The counties also receive liquid fuels payments in June every year. Elder said Mercer County’s December allotment is almost exactly the same as it was for the previous June.
The problem is, Mercer County is going to need about $3 million every year for the next decade.
“We look at these amounts and ask, ‘What is the gap, how big is the gap we need to fill,’” Elder said.
The county is responsible for 247 bridges, with three being culverts 4 feet long or shorter. The remaining spans range from culverts 8 feet long up to Mercer County’s longest bridge, the 314-foot-long Oakland Avenue Viaduct in Sharon.
Mercer County has to find the money to replace 55 spans — more than 20 percent of its total bridge infrastructure — in the next 10 years. That includes 20, including Kelly Road and Ohl Street, that will be paid for through the state TIP.
The county has to find enough money, about $3 million a year for the next 10 years, to replace 35 more bridges.
For the next decade, the pressure will be unusually acute, Elder said, because an unusually high number of its bridges will reach the end of their useful life during that time.
Among the spans most in need of replacement are the steel grate-deck bridges, which have deteriorated due largely to weather conditions and the use of salt to cut ice and snow during the winter, which has caused severe rust. One of the two Kelly Road bridges in need of replacement is an example of that problem, Elder said.
However, he said the $30 million estimate could turn out to be a worst-case scenario.
Some of the bridges on Elder’s list have steel grate decks and concrete abutments. He said the decks will need to be replaced, but the abutments might still be sound.
“The steel open bridge types are the ones that we need to tackle the quickest,” he said. “If we assume a full bridge replacement but we only have to replace the steel, we’ve just cut the cost in half.”
To put the gap between state funding and the financial need in perspective, Elder said the county receives just about enough funding through the gasoline tax and the fracking well fees to replace one bridge each year.
“That means you need to have a bridge that lasts 247 years,” he said.
Elder said county officials will have to decide whether — and if so, how much — local tax revenue to spend to repair its bridges in the short term.
“The challenge is to find the funds to do what needs to be done,” he said.