Behind the ‘Bridge in a Backpack’ That Could Go National

Students at the AEWC, with a piece of composite "bridge in a backpack" cable in the background. (Photo: Bangor Daily News)

It sounds like the start of a wonky transportation joke: Have you ever crossed a "bridge in a backpack"?

Residents of Pittsfield, Maine, are doing so every day, and the concept could eventually be used on a national level. The innovative technology, viewed firsthand yesterday by Transportation Secretary Ray LaHood, was developed by researchers at the University of Maine's Advanced Engineered Wood Composites Center (AEWC).

The AEWC's materials are made from innovative carbon fiber tubes that are inflated to surround a steel support structure built in the shape of the bridge span. After the tubing is fused to the steel beams, concrete is poured in to fill the tube and create a bridge span -- a process that took just one hour to complete when used on the Neal Bridge in Pittsfield.

The bridge's nickname, in fact, is a bit misleading; one backpack can carry enough deflated fiber tubing to make a full arch for the bridge. The Neal span required 23 arches to run 36 feet, and the new technology will soon be used on a 46-foot span in North Anson, Maine.

Yet the technology's potential to dramatically cut bridge construction time, while decreasing the carbon footprint of the process, has attracted a promise of $20 million in new capital from Advanced Infrastructure Technlogies, a private Florida-based firm. LaHood was drawn to view a lab demonstration of the technology at the invitation of one of Maine's House members, Rep. Michael Michaud (D).

LaHood told the Bangor Daily News after the event that the U.S. DOT could broaden the technology's use once it wins approval from the American Association of State Highway and Transportation Officials (AASHTO), which helps states and localities test and implement new construction methods.

Michaud could also get a chance to help implement the "backpack" bridge thanks to his seat on the House transport committee, which will assemble the next long-term federal infrastructure bill sometime in the coming months.

After the jump, check out a picture of the Neal Bridge in Pittsfield.

(Photo: U. of Maine)