Just as Francois Hennebique expanded the use of concrete in 1879 by developing concrete structures featuring steel-tensioned reinforcement, enabling Eugene
Just as Francois Hennebique expanded the use of concrete in 1879 by developing concrete structures featuring steel-tensioned reinforcement, enabling Eugene Freyssinet in 1907 to design the first prestressed steel-reinforced concrete bridges, recent structural engineering advances have been predicated on a combination of building materials to optimize overall performance. Likewise, hybrid-composite beam (HCB) technology employs a synergy of materials Û fiber-reinforced plastic, self-consolidating concrete (SCC), and high-strength steel prestressing strands Û to produce a lightweight, strong and durable structural member.
The HCB is simply supported. The profile of its compression reinforcement using SCC follows a parabolic curve, emulating the funicular shape of the applied dead load and live load moment envelope. The vertical component of thrust in the compression arch also results in a dramatic reduction in the amount of shear that has to be carried by webs of the FRP shell. In its basic configuration, the beam essentially functions like a tied-arch in a glass box.
The same technology can be employed to produce beams of variable depths or widths, using the closed-mold, vacuum-assisted resin transfer method (VARTM). The beams also can be made continuous over several supports, as in the case of the eight-span Knickerbocker Bridge currently under design for Maine Department of Transportation. In effect, the HCB allows FRP materials to find their form for transportation structures.
Notes HCB licensee Glenn Burkett, president of Innovative Infrastructure Solutions Canada, After 25-plus years’ experience introducing new high-tech road/highway-related products to many parts of the world, I have had the pleasure of introducing one of the most dynamic, unique technologies to our associates. In a recent meeting with one of Canada’s largest road construction companies, I was asked if there was any downside to the [composite bridge technology] business, and to be completely honest, I could not come up with one.