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Forest Products Laboratory
One Gifford Pinchot Drive
Madison, WI 53726-2398
Phone: (608) 231-9200
Fax: (608) 231-9592
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Scientists Study True Longevity of Timber Highway Bridges

Bridge No. 738 located in Yakima County, Washington, remains in satisfactory condition after 75 years of service. James Wacker, USDA Forest Service
Bridge No. 738 located in Yakima County, Washington, remains in satisfactory condition after 75 years of service. James Wacker, USDA Forest Service
Snapshot: Do timber bridges last longer than concrete or steel bridges in similar climates This national project aims to generate more reliable data about the true longevity of timber bridges in the U.S. and allows for more accurate life-cycle assessments in the future.
Summary:

Timber bridges are an indispensable component of the U.S. highway system, especially on secondary rural roadways. The current National Bridge Inventory database includes approximately 48,000 bridges that utilize timber as a primary structural component for the superstructure. As many engineers begin to implement life-cycle cost analyses within the preliminary bridge design phase, there is a significant need for more reliable data on the expected service life of highway bridges. Many claims are being made about the expected longevity of concrete and steel bridges being 75 years or more, but few are based on actual performance data. In-depth bridge inspections were conducted at over 125 sites among the major U.S. climate zones to generate more accurate service-life data for timber bridges.
Princpal Investigator(s):
 Wacker, James P.


Research Location:
  • Bridge inspections were conducted in the states of Washington, Oregon, California, Louisiana, Mississippi, Alabama, Georgia, North Carolina, Tennessee, Iowa, Wisconsin, Minnesota, New York, and Maryland.


Forest Service Partners:
  • Pacific Northwest Regional Office Engineering
  • Rogue River-Siskiyou National Forest


External Partners:
  • Federal Highway Administration
  • Iowa State University
  • Laminated Concepts Inc.
  • Louisiana Transportation Research Center
  • Mississippi State University
  • T-Williamson Timber Engineering, LLC
  • University of Minnesota-Duluth

Fiscal Year: 2013
Highlight ID: 434
 
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