You are here: Home / Research Topics / Research Highlights / Individual Highlight

Research Highlights

Individual Highlight

America's Historic Covered Timber Bridges

The Portland Mills Covered Bridge in Parke County, Indiana, has a Burr-Archtruss design. James Wacker, Forest ServiceSnapshot : Covered wooden bridges proliferated in the United States in the mid-nineteenth century. Today an estimated 800 covered bridge structures remain as cherished links to the technological heritage of the United States. The through-truss designs vary from the Kingpost trusses built in the craft tradition to the engineered Burr arch and Paddleford trusses. Covered bridges are links to the past and the pioneering bridge-building efforts and, as such, are considered important early American transportation structures to preserve for posterity.

Principal Investigators(s) :
Wacker, James P. 
Research Station : Forest Products Laboratory (FPL)
Year : 2011
Highlight ID : 284


Partnering with the Federal Highway Administration and National Park Service, the Forest Products Laboratory (FPL) has taken the lead in conducting research efforts aimed at preserving and/or restoring historic covered bridges. Several collaborative studies have been initiated to improve engineering evaluation methods, increase the durability of the bridge components, and develop new historic structure documentation techniques. Technology transfer efforts have included K-12 educational modules, historical videos, and technical conferences.

Forest Service Partners

External Partners

  • Federal Highway Administration
  • Iowa State University
  • National Center for Wood Transportation Structures
  • U.S. Park Service
  • University of Minnesota-Duluth

Program Areas