DARKE COUNTY — We don’t often give much thought about roadway bridges while driving through Darke County, but without them, direct travel from Point A to Point B would be impossible.
Fortunately, the Darke County Highway Department is dedicated to keep the bridges on county roads traffic-ready and doing so in the most efficient manner possible.
At the Highway Department’s garage on Greenville-Celina Road, space has been set aside for the workers to construct pieces of bridgework for installation on county roads.
“For the past two years, we’ve been doing the fabricating ourselves,” said Highway Superintendent Shane Coby.
The department has two, four-man crews working on bridge components. In its third year, the county’s bridge teams have increased their efficiency and output.
Coby explained that two years ago, the department was only able to put together one bridge in the shop. A year ago, two were constructed.
However, plans for 2016 are more ambitious. Darke County Engineer Jim Surber says that the department is fabricating four new steel structures to replace deficient bridges on Brown, Shaffer, Braffetsville-North, and Jaysville-St. Johns Roads this coming year.
“There will also be nine additional bridge construction and rehabilitation projects performed during next year,” he said.
By having the County Highway Department do the work, Coby and Surber estimate it saves taxpayers 60 to 70 percent of the cost that would otherwise go to contractors.
“We could do more if the law didn’t limit us,” said Surber.
Since 2003, Ohio law prohibits a county engineer from building any bridge costing more than $100,000, and requires that bridges costing more than this estimated amount be given to a contractor.
“Thirteen years of price increases, coupled with no increase in this arbitrary amount, makes it increasingly harder for taxpayers’ money to be used efficiently in bridge work,” Surber said.
The majority of the raw steel used is purchased from First Rate Industries in Hollansburg, Ohio It is then fabricated during the winter by department personnel for construction from March to November. The steel is cut, drilled, fitted, welded and bolted into components that are then disassembled.
The disassmbled pieces are then sent to AZZ Galvanizing in Muncie, Indiana. Surber says that galvanizing the steel eliminates the need for periodic painting, and that rust will be prevented for approximately 35 to 45 years.
During the actual construction process, the old bridge is removed, new abutments are constructed to provide the correct span and skew of the new bridge. The galvanized, steel superstructure components are set in place and bolted together. The timber deck, either four or six inches thick, depending upon particular design, is then hand-nailed and secured with galvanized clips to the beams. The job is finished by installing a layer of asphalt, a layer of membrane waterproofing, then a final coat of asphalt.
Building the bridge in components eliminates the need for cranes and other heavy machinery, and entire projects are performed with available county equipment.
Surber says the county is either “blessed” or “cursed” when it comes to bridges on local roadways.
“The average Ohio county has 297 bridges over a 10-foot span, but Darke has 531 which makes it not only first in Ohio, but tenth in the entire nation behind counties in Western states having two to three times the area of Darke,” he said.
The high bridge count is due to the county’s relatively large size, its high saturation of public roads in a rural area, and terrain considerations.
“Before settlement, Darke County was predominantly forested wetlands, eventually transformed into highly productive farms by an extensive network of enhanced and man-made drainage,” he said.
Surber calls the county’s bridge maintenance and construction tasks “a tremendous challenge.”
“With static revenues for the last seven years and constantly increasing prices in bridge materials, we are always seeking more cost-effective methods of bridge construction and maintenance,” he said.
Though the work often goes unnoticed by motorists — until the point a road is closed for bridge construction — Surber wants county residents to know the Highway Department is stretching taxpayer dollars for the maximum benefit.
“We want to let people know what we’re doing, and how we’re doing it,” he said. “Construction by county personnel, using improved and efficient methods, makes the best use of the tax dollar.”