Composite beam passes load test

A railroad bridge made with hybrid-composite beams designed by John Hillman successfully supported a full-sized locomotive in a recent load test. The Hillman-Composite Beam was fabricated and tested in collaboration with the University of Delaware's Center for Composite Materials (CCM).

On Nov. 7, 2007, a full-size locomotive traversed the first composite railroad bridge in the world with John Hillman, inventor of the unique hybrid-composite beam that formed the structure of the bridge, on board. Hillman, senior associate with Teng & Associates in Chicago, patented the technology in 2000 under the name "Plasticon-Optimized Composite Beam System."Now known as the Hillman-Composite Beam, or HCB, the material was designed to be stronger, lighter, and more corrosion resistant than the standard concrete and steel used in infrastructure applications.

After patenting the concept, Hillman turned to UD-CCM several years ago for support in fabricating and testing the beam. The Center's expertise in composites manufacturing, augmented by Prof. Dennis Mertz's knowledge of bridge design and the Department of Civil and Environmental Engineering's large-scale testing capabilities, helped Hillman turn his dream into a reality.

For Hillman, the successful load test was evidence that the beam has a future beyond the lab. The test was conducted on the FAST (Facility for Accelerated Service Testing) Loop at the Transportation Technology Center, Inc. (TTCI) near Pueblo, Colorado, a transportation research and testing organization operated by the Association of American Railroads.

"Getting the beam designed, validated, and manufactured was a challenge,"says Hillman, "but beyond that, it was critical for us to get the buy-in of the railroad community. If we had tested the beam on a working track somewhere, we could have collected data about the performance of the beam, but we would not have gained the attention of the entire Class I Railroad industry."

A consortium of railways, including Burlington Northern Santa Fe, Canadian National, Canadian Pacific, Norfolk Southern, and Union Pacific, shouldered the substantial cost of the live test. "This was evidence that they were very interested in our technology,"says Hillman. He credits TTCI's Duane Otter with pushing the initiative and overseeing the testing operation in Colorado.

Constructed on the 4.8-mile-long FAST Loop at TTCI, the bridge is a 30-ft span comprising eight HCBs. "The response of the bridge matched exactly the predicted strains and displacements calculated in accordance with the limits specified in the AREMA [American Railway Engineering and Maintenance-of-Way Association] design codes,"says Hillman.

With the performance of the HCB validated and recognized by the rail community, the next step is production of a prototype for extended testing in Pueblo. "Our ultimate goal is to deploy the technology in revenue service on a Class 1 railroad," Hillman says.

Plans are also in place for the technology to be tested on two highway bridges: a 58-ft span in Illinois and a 36-ft span in New Jersey. The bridges were designed by Teng, with project funding provided by the Federal Highway Administration through the IBRD (Innovative Bridge Research and Design) Program. Hillman has recently established a separate business entity, HC Bridge Company LLC, to promote commercialization of the technology.

"Our collaboration with CCM was a real success story,"Hillman says. "They were able to assist us with not only structural validation but also - and maybe even more importantly — composites manufacturing. This was a relatively large and complex composite part to develop, and the real benefit of working with CCM was that we were able to develop an efficient and repeatable process to manufacture the beam. It's one thing to produce a single prototype; it's another to develop a systematic manufacturing method that repeatedly yields consistent parts. Without a timely manufacturing process, the economy of the HCB wouldn't exist."

Hillman is especially grateful to CCM Associate Scientist Nick Shevchenko, who led the innovative large-scale processing and tooling effort. "Nick's attitude toward the work we did on the HCB far exceeded his obligation as a researcher at UD-CCM," Hillman says. "He approached the solution to each obstacle as if it were his own invention. When it seemed as if we had hit an insurmountable task that could not be overcome, Nick went beyond being the professional colleague determined to find an academic solution and became the friend that refused to let you fail. Nick's perseverance often gave me the energy to keep pushing forward myself. His technical knowledge of engineering and manufacturing were tremendous assets to this research, but his dedication to success was quite literally invaluable."

In addition, Hillman acknowledges the contributions of several industrial partners in the project, including Owens Corning, which donated its "Flow-Tex"quad-weave material for the resin infusion process; Ashland Specialty Chemicals, which supplied the resin; Elliott Company, which provided the foam; and Hardwire LLC, whose steel reinforcement was used in the beams.

Development of the beam was also enabled by a grant from the Transportation Research Board (TRB) through its IDEA (Innovations Deserving Exploratory Analysis) HSR (High Speed Rail) program.

In addition to the commercial potential of the HCB, Michael Chajes, Interim Dean in the UD College of Engineering, is pleased that the project provided a learning opportunity for students. Two civil engineering undergraduates spent 10 weeks in the summer of 2005 working on fabrication, testing, and design of the HCB in the Composites Manufacturing Lab and the civil engineering structures lab. Hillman spent time on site at UD to co-advise the two juniors.

"Thanks to all the work that has been done with CCM on the composites manufacturing process since then, the beams can now be manufactured in a day,"Chajes points out. "But two years ago, the team was facing a number of fabrication challenges, which turned out to be a great experience for our students because it provided them with insights into the research process that they wouldn't have gained if everything had gone smoothly."

For CCM Director Jack Gillespie, the project is a perfect example of how the contributions of many partners can take an innovative idea from concept to field application. "It also demonstrates successful interdisciplinary research,"he says. "The beams are intended for structural applications, which meant that the involvement of civil engineers was critical to complement our knowledge and expertise in composites manufacturing."

While Hillman is eager to recognize the contributions of the many partners involved in the project, he was also willing to accept the blame had the load test failed. "I don’t mind telling you I was nervous,"he says, "given there was only one direction to point the finger."

Fortunately, there will be no finger pointing or looking back on this project-only looking ahead to more widespread use of a technology that shows great promise as a replacement for traditional civil infrastructure materials.