Contact: Jeremy C. Nagel, 517-323-6585
LANSING — A small group of soybean growers and state transportation officials gathered in Holt June 4 to discuss an issue of evergreen importance to farmers and motorists across Michigan: the integrity of the state's bridges. The Michigan Soybean Promotion Committee hosted the gathering, centered around a presentation from Mike Steenhoek, executive director of the Iowa-based Soy Transportation Coalition (STC).
Formed in 2007 and composed of 12 state and two national-level soybean interest groups, STC has earmarked a pool of grant funds specifically targeting states interested in upgrading their bridge evaluation processes—particularly the thousands of small, rural bridges farmers rely on for getting harvested crops to elevators and other transshipment facilities. An ambitious experiment in the efficacy of public-private partnerships, STC's program offers states grants of up to $10,000 to underwrite the expense of piloting structural health monitoring technology for bridge evaluation.
"Half of America's soybeans end up overseas, so maintaining solid transportation infrastructure is more important than ever," Steenhoek said. "Soybean growers are heavily dependent on almost all major modes of transportation—roads and bridges, short-and long-haul railroads, inland waterways and ports."
At the local level, deficient rural bridges are a weak link in American agriculture's transportation chain.
"We've found the problem is much more acute with rural bridges—more than with state and federally funded bridges," Steenhoek said. "Rural bridges have received much less TLC over the years, and that's the part of the system that's most sensitive with farmers
According to the U.S. Department of Transportation, Michigan ranks 16th among the 50 states in its number of deficient bridges: 1,298 out of 11,022 total—approximately 12 percent. Topping the list are Pennsylvania, Iowa, Oklahoma, Missouri and California.
Steenhoek said STC is committed to working with state and local governments, soybean grower organizations and universities to encourage the use of more advanced technology to systematize and modernize bridge evaluation.
"The problem is, bridge evaluation is somewhat subjective," Steenhoek said. "Ratings can be marginally to significantly inaccurate. That load restrictions imposed on bridges deemed deficient aren't always accurate is what concerns me.
"The public who paid for the bridge doesn't always have full access to the system they've paid for. And especially for the farmer, that's problematic."
STC's goal in underwriting the use of structural health monitoring is ultimately to save money for both cash-strapped local governments and farmers whose razor-thin profit margins are stretched by unnecessary detours around load-restricted bridges.
Existing bridge-evaluation protocols vary widely between states and counties, but are primarily based on idiosyncratic visual inspections, normally by third-party engineering staff contracted by municipalities.
"Overall the American public has been well served by that approach," said Steenhoek, but systematic, technology-based practices are finding some rural bridges in better condition than expected. A pilot program in Iowa reevaluated 16 restricted bridges with diagnostic load testing and found them to be sound enough to have those weight limits removed. Indiana is moving forward with a similar project, and that Steenhoek hopes to see Michigan follow suit.
"Visual inspection is variable and subjective, and can result in suboptimal stewardship of scarce resources and unnecessary bridge postings," he said. "Yes, of course we need more investment in our bridge inventory at all levels—local, state and national—but first we should ensure that those bridges truly are in need. We're just underscoring importance of having the diagnosis right in the first place."
Bridge management engineer Rebecca Curtis was one of several Michigan Department of Transportation (MDOT) staffers hearing out Steenhoek's proposal. She and several of her MDOT cohorts expressed interest in the STC program, and helped explain how bridge management in rural Michigan is as unique as the state's distinctive silhouette.
"Michigan is unique in classifying trucks by the number of axles, not by gross weight. We have heavier load limits in general—our legal loads are truly unique—and local agencies do their own load rating," Curtis said, referring to Michigan's system of notoriously autonomous county road commissions. "We do have standards in place to try to ensure uniformity from one county to the next, and everyone's fairly consistent in how they apply their load ratings."
Richard Katherns, MDOT's bridge inspection program manager, added that bridge load ratings in Michigan are based on federal requirements, but municipalities usually contract with private engineers for bridge evaluation services.
States can use STC grant funds to acquire improved bridge evaluation technology or implement its use. Steenhoek emphasized his group doesn't endorse any particular type or producer of these technologies—they only advocate for their use.
"We don't promote one particular technology—we're not engineers," Steenhoek said. "We just want to promote its use to arrive at better decisions. We don't mandate the technology. You decide what you're most comfortable with and what works best for you."
NOTE: Learn more about the Soy Transportation Coalition here.