The development of new timber technology may be the answer to bridge deterioration problems throughout the country, including Ada County, U.S. Forest Service officials say.
The Ada County Highway District is working with the Forest Service and Boise-based TJ International to replace the Columbia Road Bridge in Meridian with a demonstration bridge made of high-tech timber.The bridge will be constructed from MICRO-LAM laminated veneer lumber manufactured by TJ International.
The 36-foot-wide, two-lane bridge is intended to demonstrate the structural and economic feasibility of wood bridges, the Forest Service said in a news release.
Construction will begin May 1 and is expected to be completed by May 17. The Forest Service has contributed $30,000 to the cost of building the demonstration bridge.
Concrete and steel currently are the most popular bridge construction materials. But the Forest Service says 240,000 concrete and steel bridges in the United States now are obsolete and structurally deficient, including 157 of the 400 bridges in Ada County.
Researchers at the Forest Service's Forest Products Laboratory estimate that timber bridges can last at least 50 years and reduce maintenance and repair costs compared to concrete and steel.
Treated timber resists decay, fire, and de-icing chemicals that deteriorate concrete and steel bridges, the agency said.