How often did John R. Hillman, founder and president of Chicago-based HC Bridge Co., LLC, think about giving up on getting the industry to accept his hybrid bridge beam of concrete and steel with fiber-reinforced polymer materials? “Only about once a week,” he laughs.
Hillman invented the beam design in 1996 after wondering what would happen if he combined concrete and steel with a composite material. Exposure to FRPs in graduate school at Virginia Tech and the experience of working with renowned bridge designer Jean Muller inspired him to marry the “age-old technology” of the arch structure with modern-day materials. “It became a mild obsession,” he says.
Riding the train to his daily job as an engineer at Teng & Associates, Chicago, Hillman did what engineers do—scribble down calculations. The result: a glass-fiber-reinforced shell, self-consolidating concrete for compression reinforcement, and high-strength continuous steel fibers for tension reinforcement. His first chance to prove the technology came in 2002, when Lehigh University engineering professor Dennis Mertz urged him to apply for a research grant from the Federal Railroad Administration and the state departments of transportation through the Transportation Research Board’s National Cooperative Highway Research Program.
TRB员工代表尼尔·霍克斯（Neil Hawks）说：“混合复合梁无疑是独一无二的。”“尽管光束符合结构工程的原理，但其复杂材料和常见材料的巧妙组合产生了一种结构构件，比其相当于钢筋混凝土等效的结构构件。由于我们目前对更新铁路和高速公路桥梁的担忧，同时最大程度地减少了干扰，因此这些特性的需求量很高。”
With the grant, Hillman successfully tested a 30-ft-long, 17-ft-wide span comprising eight beams in Pueblo, Colo., in 2008. It supported a full-size locomotive pulling 26 heavy-axle-load coal cars. “The hybrid composite beam will be the best solution for the many situations where stronger but shallower and lighter beams are needed,” notes Hawks.
Bridge engineer created a hybrid of conventional materials and composites that can create long-lasting, noncorrosive bridges that carry heavy loads.
The beam is catching on. The second application was the $2-million, 57-ft-long High Road Bridge in Lockport Township, Ill. This year, the New Jersey Dept. of Transportation used federal research funds to apply the beams on a $1.34-million replacement of state Rte. 23 Peckman’s Brook Bridge in Cedar Grove. Coming next is the Knickerbocker Bridge in Boothbay, Maine, an eight-span, 540-ft-long, $6-million replacement structure.
“It’s a labor of love to keep moving with this,” says Hillman of developing his patented technology. “Every time I did a major test, part of me hoped for a failure so I could move on. Then it would succeed, so I couldn’t stop.” Moreover, his colleagues at Teng gave him moral and engineering support. “Colleagues who I deem smarter than I—they told me it’s a great idea. So I couldn’t walk away from it,” he says.
