A research team from NC State is designing and testing a carbon fiber retrofit system that strengthens deteriorating bridge support beams. Earlier this month, the team conducted a final full-scale beam test that was successful. The inexpensive and easy-to-install technology isn’t a permanent solution, but it could allow aging bridges to accommodate larger vehicles, said Brian Hanks, state structures engineer with the NCDOT.
“If you put a posted sign on a bridge not allowing a certain weight vehicle to go across, that could hurt the economy. I mean, industry, agriculture, commerce, they cannot cross the bridge, they’ll have to find a different means. The bridge may be in good shape, it just can’t carry the load for these bigger trucks. So technology like, you can apply to it, adds strength to the bridge until maybe a replacement can be scheduled for it.”
Hanks said a small bridge replacement can cost upwards of $750,000 for a small span and take between two to three years to complete. According to a standard bridge report from Feb 1, 2019, there are more than 13,533 bridges across North Carolina, many of them in the eastern part of the state. 1,783 are structurally deficient and 3,017 that are functionally obsolete.
The NCSU team will continue their research for another year testing the retrofit system on dozens of types of beams. Their goal is for NCDOT workers to be able to install the technology in one day.