InfrastructureUsing Hemp to Repair Deteriorating Kentucky Bridges

Published 26 November 2019

Bridges are a crucial component of Kentucky’s infrastructure — providing access between regions and cities and linking workers to jobs. But as traffic continues to increase, bridges across the state are aging at an accelerated pace. Experts say that 7 percent of Kentucky’s bridges—or 1,100 bridges — are classified as “structurally deficient.” Researchers have developed innovative products — dubbed CatStrong — for restoring bridges.

Bridges are a crucial component of Kentucky’s infrastructure — providing access between regions and cities and linking workers to jobs. But as traffic continues to increase, bridges across the state are aging at an accelerated pace.

According to the American Road & Transportation Builders Association, 7 percent of Kentucky’s bridges are classified as “structurally deficient.” What exactly does that mean? Well, more than 1,100 of them are in poor condition. 

“Every bridge in the nation is inspected for deficiencies, at a minimum, once every two years. Bridges with known issues are inspected more frequently to ensure public safety,” Issam Harik explained. “Each bridge has to be assessed individually in order to understand whether repair is needed.”

When a repair is needed — that’s where Harik comes in. As a professor in the Department of Civil Engineering at the University of Kentucky, he offers much more than advice.

Kentucky says thatsince 1994, Harik has been at the helm of a group of students researching the deployment of fiber reinforced polymer (FRP) composites in bridges and buildings. Through funding from the Department of Defense, Federal Highway Administration, the Kentucky Transportation Cabinet, The National Academies and the Kentucky Science and Engineering Foundation, he and a team of talented students developed innovative products — dubbed CatStrong — for restoring bridges.

When asked why the name “CatStrong”? “Well, I am proud of our Wildcat legacy, and the products are very, very, strong,” Harik said.

Currently, CatStrong rod panels and fabrics come in different strengths. The strongest version can resist 195,000 pounds per foot of width — yet can be easily applied by one worker.

“The CatStrong family of products were developed to meet the repair needs of bridges when no other products were available on the market that satisfy the retrofit requirements,” Harik explained. “All CatStrong products are tested experimentally and/or via computer models in order to assess their strengths and limitations.”

Using remarkably resilient carbon fiber fabrics, panels and wraps, CatStrong has successfully restored more than 35 bridges by strengthening beams, columns, piles and walls. The lightweight product has yielded impressive results due to its ease of application.

“Whether in a bucket or platform truck or on special scaffolding over rivers, valleys, roadways, etc., this helps significantly with reducing the number of man hours and traffic control — which is usually the biggest expense on a job,” Abheetha Peiris explained.