Concrete Girder & Floorbeam
National Register of Historic Places status:
80th Street across the Little Volga River southeast of Maynard, Sections 25 & 36, T92N-R9W (Harlan Township)
The 80th Street Bridge is eligible for inclusion in the NRHP under Criterion C as it does meet registration requirements outlined in the MPD as it is a large girder and floorbeam bridge of an exceptional span length. The registration requirements include girder spans of over 50' in length as exceptional. With a main span of 55', this bridge does meet that requirement. The 80th Street Bridge does not meet any other registration requirements and is therefore not eligible under any criteria. The Concrete Girder & Floorbeam bridge (Type 103) commonly consists of two parallel rectangular girders spanning between supports (abutments and piers), spaced apart a distance approximately equal to the width of the roadway. Sidewalk slabs are usually cantilevered beyond the girders. More than two girders are used in some cases. The girders support transverse cross beams (floorbeams) which are spaced to properly support the deck slab. The formwork and steel reinforcing for the girders, floorbeams and slab is commonly built all together so that the concrete can be continuously poured making all three structural members integral.