Researchers Say Weather Takes a Toll on Bridges, Too

Mention "bridges" and "University of Cincinnati," and many people will think of

UC alum Joseph Strauss

(Engineering, 1892), who engineered and built the Golden Gate Bridge. UC bridge expertise indeed spans the country. But Strauss isn't the only member of UC's "Bridge Club."

UC plays host to some of the country’s leading experts in bridges from construction through in-service use and up to old age.

UC’s Infrastructure Institute (UCII) 

experts specialize in assessing and monitoring the condition and health of civil infrastructure systems.

Although UC’s bridge experts have often been standing in the shadows, playing a supporting role since the UCII was formed in 1989, they have been in the limelight more in recent years because of such events as the August 2007 Interstate 35W bridge collapse in Minneapolis or closer to home in 2008 when a truck carrying an oversized load struck an I-275 overpass.

To assess bridge conditions, UC experts are often tapped by transportation agencies as well as national media outlets to explain them to the public. For her “Focus on Technology” segment on WVXU, the Cincinnati NPR station, Ann Thompson interviewed three of the UCII members: team leader, Professor Art Helmicki, Associate Professor Jim Swanson and Research Associate Professor Victor Hunt. 

UCII's success is built on an integrated, multi-disciplinary team of civil, electrical, computer, mechanical and materials engineers from a broad cross-section of the faculty in UC’s College of Engineering.

“Everyone wants to jump on the bridge bandwagon,” says Swanson with a smile. Swanson, an associate professor of structural engineering in the Civil and Environmental Engineering Department, was interviewed in late 2008 also on WVXU regarding the work being done on the Combs-Hehl bridge on I-275 near Coney Island and Kellogg Avenue.

UCII draws bridge expertise from a wide variety of laboratory and analytic facilities at the university as well as a number of full-scale field research sites located off campus.

Helmicki, head of the Department of Electrical and Computer Engineering, calls it a “marriage of necessity.”

“The work could not be done by one group or one department,” he says. “It requires a blend of knowledge — a constant mix. At its heart this is a very multidisciplinary issue.”

Since its inception, UCII has been involved in the testing and evaluation of several structures, including more than 60 bridges in the state of Ohio. UCII has developed and applied a number of unique experimental and analytic tools in the evaluation of both laboratory model and full-scale civil infrastructure systems including modal testing, truckload testing and field-calibrated finite element modeling.

A major thrust of research has been to conduct a comprehensive scientific study of what causes bridges to weaken or fail (such as traffic, the environment and damage, deterioration and defects) during fabrication and construction, through in-service use, up to old age.

“We are truly studying the life of a bridge,” says Helmicki, “cradle to grave.” One bridge in particular, in Ironton, Ohio, is providing detailed information regarding shivers, stress and strain excursions.

“The bridge automatically sends text messages alerting us to changes in conditions,” says Helmicki. “There's also a high-speed Internet connection at the bridge that allows posting of the data in real time to a dedicated Web site for the monitor.”

Hunt points out that there is a variety of tools, from “high tech to low tech” for assessing the behavior and status of health of a bridge.

“If a bridge is deficient, it could mean different things,” Hunt says. “It could be functionally obsolete, meaning it was built to a set of codes that is no longer in use. Or it could be showing signs of deterioration, which means that it is structurally deficient. In this case, the bridge might be posted for lower loads or scheduled for rehabilitation.”

Helmicki noted that the bridges between Ohio and Kentucky, such as the Brent Spence and the Daniel Carter Beard bridges go through a series of visual inspections. An assessment might be made to limit the loads while studies are completed.

“There might be retrofitting of some components until the bridge is 100%,” he adds.

Such objective, quantitative information and assessments provide a critical understanding of overall life-cycle behavior, performance and cost of these important links in transportation system. This understanding permits more efficient and improved designs for new structures, as well as better management of the large numbers of existing structures in the nation’s current inventories.

The federal government created the National Bridge Inspection Standards (NBIS), which require periodic inspection of all the nation’s bridges after the 1967 collapse of the Silver Bridge between Point Pleasant, W.Va., and Kanauga, Ohio.

UC’s bridge experts agree: today Ohio bridges are safer than many, they say, pointing out that the Ohio Department of Transportation (ODOT) tends to take a conservative approach to bridge inspection.

“ODOT likes to stay ahead of the curve on maintenance and inventory,” says Helmicki. As an example, he recalls a time "a while back" when ODOT called in the UCII bridge experts because GE needed to transport turbines weighing millions of pounds down state highways to Marietta.

“Even with GE breaking the turbines down into the smallest components possible, ODOT was still concerned about the load on the bridges so they called us in,” Helmicki explains. “They had us test the bridges before, during and after passing the load over them."

“From a safety factor they’re very conservative with their modeling assumptions because you have people’s lives at stake. Our bridges in Ohio are very safe,” says Hunt. “ODOT is burdened with this very old infrastructure that was built right after World War II on a shoestring budget. Personally, I think they’re doing a heck of a job.”

Swanson points out that an “obscenely large” number of goods and services flows through the state of Ohio.

“Ohio has the fourth-largest transportation infrastructure in the country,” he says.  “ODOT monitors 42,000 structures in the state, of which 12,000 are owned by Ohio.”

Indiana might be called the “Crossroads of America,” but Ohio’s got its share of roads to cross. Helmicki cites ODOT statistics and says that Ohio has quite a load to bear when it comes to infrastructure:

• 2nd largest inventory of bridges 
• 4th largest interstate system 
• 4th most operating rail routes 
• 5th highest volume of overall traffic 
• 5th highest volume of truck traffic 
• 7th largest highway network 
• 10th highest transit ridership 
• 106 federally designated airports 
• 716 miles of navigable waterways 
• 7th largest state economy in the United States

And the University of Cincinnati Infrastructure Institute is keeping an eye — or a monitor — on much of it.

The work of UCII has been funded by several companies, municipalities and numerous agencies, including the Ohio Department of Transportation, the Federal Highway Administration and the National Science Foundation.