McClure provided survey, utility coordination, roadway, drainage, bridge, bridge hydraulics and geotechnical design for the replacement of an existing 77’-0” x 25’-0” concrete rigid frame bridge on North 15th Street in Adel, Iowa. The existing structure had reached the end of its useful life and was in need of replacement. Constraints along the existing roadway corridor, including several utilities and narrow right-of-way, dictated the replacement structure be constructed on the existing horizontally curved alignment. Hydraulics and scour analysis were completed using HEC-RAS to properly size the hydraulic opening and ensure adequate scour protection.

A 100’-0” x 36’-0” Continuous Concrete Slab (CCS) was selected as the replacement structure type, which allowed for minimal profile adjustment and approach roadway reconstruction. The width was oversized slightly to facilitate construction of a straight bridge, minimizing complexity and ultimately providing cost savings to the City compared to a horizontally curved structure. The bridge is skewed 15-degrees and utilizes a 6% superelevation for its entire length, with the superelevation transitions happening on the reconstructed approaches. The concrete slab superstructure is supported by integral abutments on driven steel piles and individually encased P10L type piers.