A suspension bridge spanning Rattlesnake Creek on the outskirts of Missoula, Mont.s Rattlesnake Wilderness features small-diameter waste wood and waste plastic in what designers say is the first-ever application of these materials in a bridge. We are trying to take these unique construction materials to another level, says Dave Atkins, a U.S. Forest Service economic action program coordinator.

No Waste. Footbridge features unsellable wood, plastic waste products and recycled tires

The 90-ft-long, 8-ft-wide bridge is part of a $10-million Forest Service program that aims to let people see the value of using this waste wood material, says retired Forest Service products specialist Dean Graham, who devised the concept in 2000.

The $250,000 bridge is built of lodgepole pine trees killed by beetles in Idahos Nez Perce National Forest. The trees are debarked and doweled down to 6-in. diameters. Because it isnt milled, the wood maintains its structural integrity, says Graham. To connect the wood rounds, weve been experimenting with powder-driven nails that are normally used to fasten metal plates to concrete, he says. The nails sink deeper into the wood and penetrate at different angles.

Deck. Pieces can be replaced as needed.

For side trusses, some rounds are milled in half because the flat surfaces are more stable, says Brad Miller, project engineer with designer HDR Inc., Omaha. The 4 x 12-in. deck planks are made from wood flour and PVC plastic, in equal proportion. Rubber mats made from recycled tires protect the deck surface from horse traffic. We can unbolt and replace pieces without having to dismantle the bridge, Miller adds.

Graham says the materials could find use in high-end homes or buildings once building professionals are made aware