Composites professionals have been working for almost fifteen years to attain wider adoption of products used for bridge applications by departments of transportation and civil engineers. So where do things currently stand? Here’s what you need to know:
#1: Knowledge and Enthusiasm for Composites Is Growing
More than 1,500 people attended the International Bridge Conference in Pittsburgh in June. Members of the Transportation Structures Council, a part of the American Composites Manufacturers Association (ACMA), exhibited at the conference. The group’s larger aim is to obtain language in the transportation bill that promotes the specification, design and construction of long-life bridges and other highway structures.
According to John Busel, director of the Composites Growth Initiative for ACMA, there were representatives from 35 departments of transportation (DOT) and 12 other agencies and municipalities focused on bridge product specification. At past conferences, attendees wouldn’t know anything about composites and would ask very broad questions, says Busel.
This year, the inquiries were more detailed, and TSC members talked about what composites could do and how they could be used in specific situations. “That tells me that FRP is becoming more mainstream and that people understand that it’s one of the main materials that can be used for infrastructure,” Busel notes.
However, interest and enthusiasm have yet to become business. Dan Richards, CEO of ZellComp, says he’s been getting a lot of calls about his pultruded FRP bridge deck system, but it’s not enough. “There’s no money in the state DOTs, so the funds just aren’t there for infrastructure at the moment,” he says.
#2: Composites Should Cooperate with Other Materials
Dan Witcher, corporate chief structural engineer for Strongwell, thinks the best strategy for composites is cooperation with other materials. “Rather than be a stand-alone component in some of these infrastructure systems, we should aim for integration into the construction system as a whole,” he says. FRP rebar reinforcement in conventional concrete, for example, is about 10 percent more expensive than concrete alone, but effectively addresses weight, corrosion and deterioration challenges. “For that cost, it’s practical to use this material, which has a much better life cycle,” Witcher adds.
“The composite people might not like to hear this, but I always emphasize the fact that I’m working with a hybrid member,” says John Hillman, president of HC Bridge Company. The product in question is a hybrid-composite beam comprised of fiberglass, steel and concrete. While 95 percent of the strength and stiffness comes from concrete and steel, fiberglass still serves an important function. It is a means of placing the concrete and anchoring the tension reinforcement, but it also transfers the shear loads and provides the corrosion barrier necessary to give the structure longevity.