Researchers at Iowa State University’s Bridge Engineering Center are joining with counterparts at a federal accelerated bridge center based at Florida International University to create ways to replace bridges faster. The ISU center’s director, Brent Phares, says they’ll get approximately $800,000 from the U.S. DOT over the next two years for research.
“It’s not just all about building bridges faster, it’s more about limiting the amount of time roads are closed to the traveling public,” Phares says. He says high-volume traffic areas in cities and also bridges along interstates in rural areas like Iowa are part of the focus.
Phares says the detours are often much longer than the original route– causing drivers to use many more resources. “Additional travel time, they use additional fuel which causes additional pollution. Additional miles, which causes additional wear and tear on their vehicles,” Phares explains.
One new technique was recently used by the Iowa DOT to replaced a 1930 bridge on State Highway 92 just outside Massena in western Iowa’s Cass County. The new bridge was built next to the old one and the old bridge stayed open during construction.) Once the new bridge was done, the old bridge was torn down and the new bridge was rolled laterally into line where the old bridge sat. The construction of that bridge took only nine days.
Another idea is to use self propelled transporters so a new bridge can be built some distance away from the old bridge. “They are basically multi-wheeled vehicles, and then you drive the vehicle down the existing alignment and you drop it (new bridge) very carefully in place in the existing alignment,” according to Phares. “And again, the down that you have is pretty minimal.”
He expects their research will be conducted in the lab studying new techniques, but some will also be out in the field. “Also testing existing bridge details and how they function, how they perform in a bridge that is constructed in an accelerated environment. Because there are some differences in the loads that those bridges see,” Phares says. The researchers need to find another 400-thousand dollars in matching grants for a total of one-point-two-milion dollars of bridge research over the next two years.
The University of Nevada-Reno is also a partner in the project.