Cincinnati Suburban Experiments With Longer-Lasting Plastic Bridge

Thu June 05, 2008 - Midwest Edition
CEG




CINCINNATI (AP) A plastic bridge is taking shape in suburban Cincinnati, promising a longer life than a conventional concrete-and-steel bridge.

The 22-ft. (6.7 m) span in Anderson Township is made of composite deck and beams molded into single panels and held together with epoxy. It won’t corrode or be prone to cracking or salt damage because it has no joints between its deck and beams.

The bridge cost $740,000, funded by a federal grant. While composites have been used in decks and other construction for a decade, they are expensive compared with concrete and steel.

The bridge should open in a few weeks.

Experts could not provide the cost of a comparable steel-concrete bridge because of several variables.

“This is newer technology, and as we get better at using it, that will help. As we get more experience and more use, some of the costs will come down,” said Scott Reeve of Composite Advantage, the Dayton company that built the panels.

The panels are made of fiberglass fabrics wrapped around a fiber-enforced foam core, infused with vinyl resin.

“It’s similar to what’s used in boats because it’s good for moisture, corrosion and impact. It’s very durable,” Reeve said.

Composite Advantage, a two-year-old company, was spun off from the National Composite Center technology incubator in Kettering.

“They don’t corrode,” Reeve said. “Composite tanks have been buried underground for 45 years, they dig them up, and there is no problem. … We see no problem with (bridge panels) lasting 100 years,” compared with about 70 for a conventional bridge.

Hamilton County bridge engineer Tom Brayshaw said the panels should last the life of the bridge — and then some. The bridge has eight panels, each weighing 5,500 lbs. (2,490 m).

“That ends up being about one-fifth the weight of a concrete-steel bridge,” Reeve said.

When the bridge reopens in a few weeks, motorists won’t notice any difference, Brayshaw said. The paint produces the concrete gray color typical of traditional bridges. The deck will be covered with asphalt, and guardrails will be installed before the bridge reopens.

Brayshaw said University of Cincinnati researchers, who have already been tracking test panels, will gather data from sensors in the bridge.

In addition to normal traffic — fewer than 1,000 vehicles a day — the bridge will be tested by driving gravel trucks over it repeatedly to see how it responds to heavy loads, Brayshaw said.