Rush County, Ind., to use new weight-load technology to test integrity of small bridges

Updated Apr 14, 2016
The Smith Covered bridge is one of several small bridges in Rush County that will be tested with the new technology.The Smith Covered bridge is one of several small bridges in Rush County that will be tested with the new technology.

Mark Bacon is a corn farmer and county commissioner in Rush County, Ind.,where nearly three dozen bridges are closed or severely restricted with weight limits, and another two dozen are considered structurally deficient, reports. This causes heavy vehicles, such as school buses and farm equipment, to take long detours to cross some creeks.

Bacon and other local leaders around the state are looking at a new method for testing a bridge’s integrity that, they hope, will help them make smarter choices about spending scarce money on thousands of small spans throughout the state.

According to the report, the method, known as a weight-load test, was developed by Iowa State University’s bridge engineering center and will be replicated by engineers at Purdue University this summer. The method, which involves attaching sensors to strategic points on a bridge to detect when the bridge starts to shake or sway as increasingly heavy trucks cross, will be tested on a handful of county bridges to start, with more likely to follow.

“It’s like a stress test on your heart,” Pat Conner, research manager for Purdue’s local technical assistance program, which works with highway and road departments across the state, tells the news agency. The technology could replace the way bridges are now visually inspected by county-hired engineers every two years to look for cracks or other indicators of stress. Conner adds that sight inspections may miss hidden flaws or may overstate a bridge’s problems, which could lead to unnecessary closures or restrictions.

Efforts to better evaluate bridges comes at a time when more than 1,500 of about 13,000 county-maintained bridges are closed or have weight restrictions, the news agency reports. The news agency reports that lawmakers have set aside approximately $580 million over the next two years for repairs to local bridges and roads, which is only about half of what is needed, according to infrastructure experts at Purdue.

Currently, the stress-test technology costs up to $10,000 a bridge, but a coalition of agriculture groups that stands to benefit from fewer detours is working with Purdue to reduce the price. For county officials like Bacon, however, the cost of testing could save money in the long run. “If we’ve got a better test that helps us know better what that bridge can stand, we’ll be a lot better off,” he tells the news agency.