The Blue Earth County Highway Department needed a way to bring the historic Dodd Ford Bridge near Amboy, Minnesota up-to-date for local traffic while preserving its status with the State Historic Preservation Office.
Originally built in 1901 for horse-and-buggy traffic, this 148-foot-long overhead truss bridge was insufficient for carrying modern farm trucks and implements across the Blue Earth River, and was closed in 2009. Since the bridge was a landmark of the community as well as a necessary artery for local farmers and emergency vehicles, it had to reopen.
The solution was to design a bridge that could accommodate modern loads, at the same time, preserving its historical significance.
To accomplish this, the overhead truss section was removed and placed to the side, onto temporary supports where it was refurbished and repaired. A new steel beam, concrete deck and abutments were put in place of the original bridge deck. This allowed for the deck to carry the load of heavy, modern farm equipment and the truss to support only its own weight.
Jeff Johnson, PE is a Structural Engineer and Project Manager at SEH and leads the Company’s Structural Practice Center in Minnesota, North Dakota and South Dakota. His experience includes several hundred bridge design and rehabilitation projects across the Upper Midwest. Contact Jeff