UMaine commercializes two hybrid composite/concrete bridge technologies

University unveils inflatable composite "bridge in a backpack" and a hybrid composite-concrete bridge system. Both are being commercialized this year.

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On Feb. 20, at its Advanced Engineered Wood Composites (AEWC) Advanced Structures & Comp-osites Center, the University of Maine (UMaine, Orono, Maine) introduced two innovative composite technologies for bridge construction, developed and tested at the AEWC lab. Also introduced were the two private Maine companies that will take these technologies to market. Joining center director Dr. Habib J. Dagher to celebrate these opportunities for infrastructure upgrades and jobs creation were Maine Gov. John E. Baldacci and Maine’s congressional delegation, including Sen. Susan M. Collins.

The first technology, the so-called “bridge in a backpack,” features rigidified inflatable composite arches. Developed with funding provided through the U.S. Army Natick Soldier Center, the U.S. Federal Highway Admin. (FHWA) and the Maine Department of Transportation (MDOT), the arch materials are fibrous tubes that can be folded and shipped in a bag to an installation site, shaped to fit bridge geometry, infused with resin, allowed to cure overnight, and then filled with concrete. The lightweight hollow tubes are easily installed and act as a stay-in-place form and a protective layer for the concrete. UMaine has two patents pending on this technology. Working with MDOT and a local contractor, the school recently used the technology to construct the Neal Bridge in Pittsfield, Maine (see “Bridge cost cut with inflatable arches," Under "Editor's Picks," at top right).

An investment team coordinated by Bangor, Maine native Brit Svoboda has formed a new company, Advanced Infrastructure Technologies (AIT, Orono, Maine) to commercialize this technology. The goal is to construct as many as six bridges in Maine in the first year and eventually design and kit bridges in Maine and ship them to installation sites across the country.

A second bridge construction innovation, which uses composite beam forms filled with concrete, is being commercialized by Harbor Technologies LLC (Brunswick, Maine). The HC Beam hybrid-composite-concrete bridge system combines the durability and flexibility of a composite stay-in-place form with the low cost and functional advantages of concrete and steel. A 70-ft/21.3m bridge girder was on display at the AEWC lab. This girder could be trucked as an empty composite box weighing 6,000 lb/2,727 kg, which then would be filled with concrete on site, as opposed to 50,000 lb/22,727 kg for a precast concrete girder. The company plans to use HC Beams in the construction of a 500-ft/152m long bridge in Boothbay Harbor, Maine, this summer.

In related news, the University of Maine also is constructing a large-structure testing lab, connected to the current AEWC test lab, where it will have the capability to manufacture and test wind blades up to 55m/180-ft long. The facility is scheduled for completion by the end of the year.