Wading thigh-deep in Browns Wonder ditch, fending off an eye-watering wind chill, Tom Bradt, Jason Lloyd and Adam Cullison carefully attached sensors to the bottom of the CR 250 E bridge early Wednesday morning, preparing for a load bearing test that could determine whether the 77-year-old structure’s 12-ton weight limit was accurate.
The trio, from the Bowen Laboratory at Purdue’s Lyles School of Civil Engineering, were connecting the sensors to equipment in a high-roof van parked on the south side of the bridge. They were using a new method of determining a bridge’s weight load, developed by the Bridge Engineering Center at Iowa State University.
Along the gravel road, huddled against the 25-mph breeze, stood Ed Ebert, senior director of grain production and utilization for the Indiana Corn Marketing Council and Indiana Soybean Alliance; and Pat Conner, research manager for Purdue’s Local Technical Assistance Program.
Joining them was Denny Maple, a Howard County multi-generation farmer who raises corn, soybeans, “a little wheat” and hogs, and who is an eight-year member of the Indiana Corn Marketing Council.
Sheltered by the Bowen Lab van was a film crew, preparing to tape interviews with Maple and others, to promote the testing method.
The technology could replace current eyes-only inspection, which can over- or under-estimate a bridge’s condition, leading either to unnecessary closures or potential safety risks.
Results of the test won’t be available for several weeks, said Megan Arnold, account supervisor with the Sandbox Agency, a publicity agency working with the soybean alliance and corn council.
Data from the test will be given to the company that provides bridge weight limits to the county, Lloyd said. They will compare what was estimated with what the test found, to produce a “real world” load rating.
The ICMC and soybean alliance have been using corn and soybean checkoff money since 2009 to research Indiana’s rural road and bridge inventory, Ebert said.
“It’s very, very important, not just for us,” Ebert said.
The CR 250 E bridge was built in 1940, according to Transportation for America, which maintains an inventory of every bridge in the country that is more than 20 feet long. While considered to be in “good” condition, the concrete slab structure shows obvious signs of deterioration. A three-foot-long rusted rent mars a steel culvert on the northeast corner of the abutment.
Maple pointed to scrapes on the bridge walls.
“It’s apparently been hit by an implement,” he said. The narrow bridge also limits access by farm equipment.
A typical combine is 15 feet wide, Maple said. An eight-row corn head is 16 1/2 feet wide — and many farmers are using corn heads that can harvest eight, 10 or 12 rows, he said.
Ambulances, fire engines and school buses are also affected by detours required by bridges too weak to carry them, Ebert said.
Wednesday’s event was the first bridge test in Boone County, he said. Three Benton County bridges were inspected last year. Ebert said another 10 to 12 bridges could be inspected over the next two years.
Of the 189 bridges in Boone County that are under the county’s jurisdiction, 15 are eligible for replacement, and 46 eligible for rehabilitation, based on a National Agricultural Statistics Service report compiled in 2015.