Saving the Past: Restoring and Preserving Historic Covered Bridges

Public Roads, the bimonthly magazine of the Federal Highway Administration, featured an article on their National Historic Covered Bridge Preservation Program, which the Forest Products Laboratory (FPL) has been a part of since its inception in 2000.

Portland Mills Bridge, Parke County, Indiana

Portland Mills Bridge, Parke County, Indiana

According to the article, titled Saving the Past, there are 800 covered bridges in the United States today, but taking care of the structures is challenging. Preserving their unique engineering and construction is historically important, but their designs cannot always handle modern traffic loadings.

The Portland Mills bridge was constructed using a Burr Arch truss.

The Portland Mills bridge was constructed using a Burr Arch truss.

The research and development arm of the preservation program is where FPL got involved. Research focused on developing ways to combine new and traditional techniques to maintain the bridges.

In the article, FPL Assistant Director Michael Ritter explains that the program “provided the opportunity to formulate practical solutions for rehabilitating, repairing, evaluating, and protecting historic covered bridges that are truly national treasures.”

Several publications were produced as a result of this research, including the Covered Bridge Manual and the Guide for In-Place Treatment of Wood in Historic Covered and Modern Bridges.