Louis N. Triandafilou, P.E. is a team leader with the Bridge and Foundation Engineering Team for the Federal Highway Administration. He sees several composite applications already in use in the transportation infrastructure segment, including decks, full-length slabs, girders, pedestrian bridges, inspection walkways and wrapping welded connections of overhead aluminum sign trusses. Plus there are numerous composite applications on the horizon, adds Triandafilou, such as prestressing strands for strengthening, rigidified tubular arches, hybrid composite beams and decks and thermoplastic bridge elements.
“My crystal ball would say it’s going to be a slow, but hopefully steady growth,” says MacNeil. “The infrastructure market is not going to just explode. It’s going to take a lot more missionary work to convince the authorities and traditional voices in the field to adopt composites.”
Competing Against Convention
Doug Gremel knows about challenging the status quo within transportation infrastructure. “Part of the problem is you have this industry that’s built up around the way it does business now,” says Gremel of Hughes Brothers in Seward, Neb. “You have to fit what you’re doing into what they do now.”
Hughes Brothers manufactures GRFP rebar, carbon for structural strengthening, GRFP dowel bars and other composite products. “We’re hitting a lot of different concrete-related products,” says Gremel. Hughes Brothers has worked on highway bridges, waterfront construction, light rail, port rehabilitations and structural strengthening projects.
Last summer, the company completed work on a bridge in Brandon, Manitoba, Canada. It provided composite rebar for two parallel bridges with seven 150-foot spans. “I think you have to be very discerning when you talk about composites in infrastructure because there are a lot of things that just make no sense at all,” says Hughes. “FRP rebar is not that big of a stretch.”
Bridge engineers are accustomed to designing reinforced concrete structures, says Hughes. FRP rebar is only marginally different than traditional materials, so the principles of reinforced concrete design remain the same. “It’s a lot easier to sell something they’re familiar with than if you come at them with a whole new FRP superstructure,” says Hughes.
As the next generation of civil engineers enter the workforce, replacing those who only learned the basics of concrete and steel in school, there will be a push for composites. “It is difficult to shift the thinking in the civil engineering world,” says Richards. “But composite decks and other structural composites have been around for a while now—and we are starting to see greater acceptance.”