The North Carolina Department of Transportation is funding a project that uses pieces of a demolished bridge to help engineers learn how bridges exposed to extreme weather conditions age.
The Herbert C. Bonner Bridge in the Outer Banks was dismantled a few years ago. Girders from the bridge have been sent to North Carolina State University in Raleigh to undergo stress testing at the college’s Constructed Facilities Lab.
Force was applied, removed and re-applied repeatedly to the girders to mimic the stresses a bridge experiences from passing vehicles.
Loads were then placed on the girders, pressing on them continuously until they broke. It took more than 200,000 pounds of force to break.
Researchers used sensors with cameras to observe how the girders responded to loads, how they moved and where cracks formed.
“What we’re trying to really investigate is the amount of pre-stressing in this structure,” Giorgio T. Proestos, the assistant professor who is leading the project, said. “Is it enough? Should there be more? Should there be less? And how does that pre-stressing change in 60 years? Based on the results of the experiment, there might be changes in the way things are done moving forward.”
The department will publish the results.