Boone County – 216th Drive Over the Des Moines River

Old Lincoln Highway 30

The existing bridge was a historical 647’ x 19.7’ four truss span structure on 216^th Drive (Old Lincoln Highway 30).  The bridge consisted of two camel back high truss main spans and two high truss approach spans. The bridge was fracture critical, structurally deficient and functionally obsolete for the 1,840 vehicles that utilized the route into the City of Boone each day.

The structure was awarded State Bridge Replacement (SBR) funds in the amount of $2,000,000, which was the first structure awarded this amount. Previously the SBR funds were limited to a maximum of $500,000 per project. 

The historical structure was mitigated by recordation of the existing structure documented in ”The Story of the Bridge”.  The recordation booklet was provided for public usage at the Boone County Historical Society and the Boone County Public Library. Copies of the document should be available for view to this day.

The new structure is a 685’-5” x 30’ Pretensioned Prestressed Concrete Beam (PPCB) bridge with a concrete deck, concrete tee piers and concrete integral abutments.  The superstructure consisted of 140’ and 130’ pretensioned prestressed concrete beams which were the longest span lengths available at the time it was built in 2000.  The tee piers were founded in shale bedrock and utilized drilled shafts for the deep foundations.  This bridge was constructed to provide hydraulic clearance that would allow the bridge to be open even during the historical floods of 1993 that closed the new Highway 30 Bridge and approach roadway that parallels this crossing less than one mile downstream from the backwaters of Saylorville Reservoir.