Located south of Marshalltown, this unique through truss bridge crosses Timber Creek.
Built in 1901 to replace a previous, lighter bridge; this bridge a single unique through truss span with riveted connections. Unlike some of the other trusses on this route, this bridge is a Pratt through truss, despite the fact that the tension and compression members both cross two panels. In addition, the endposts on this bridge cover two panels, making it a 6 panel structure.
Between Oskaloosa and Eddyville, numerous similar bridges were constructed. However, this bridge is different, as it features heavy rolled steel vertical members, and massive laced box girders for the diagonal members. It rests on stone abutments, encased in concrete.
Diagram of this style bridge
Unfortunately, no plaque can be found on the bridge. More research is being done on the bridge, to determine who designed and built the bridge.
Overall, the bridge appears to be in fair to good condition, with little serious deterioration. Some spalling has begun to occur on the abutments. In addition, a number of rivets have been replaced by high strength bolts.
The author has ranked this bridge as being regionally significant, due to the unique truss design and large size.
The photo above is an overview.