U.S. 75 Bridge over 46th Street for the Kansas Department of Transportation Shawnee County, Kansas 2005 KS ACEC Transportation Engineering Excellence Award The project design consisted of new parallel bridges, and interchange ramps at an existing at-grade intersection. The Wilson structural group provided the structural design and construction plans for twin three-span, 427-foot long (140-147-140), steel plate girder structures. There were a number of interesting and challenging features associated with the structural design: The bridge was designed using the AASHTO Load & Resistance Factor Bridge Design Specifications (LRFD). The LRFD specifications provide a more consistent approach to bridge design than earlier specifications, but also require a more rigorous design effort. The client requested attractive arch-shaped bridge piers with architectural texturing. To better predict load transfer through the arched piers, Wilson used the strut-and-tie modeling method contained in the LRFD specifications. Wilson designed full-width abutments in anticipation of future bridge widening needs. This makes it unnecessary, in the future, to construct additional driven piles through the mechanically-stabilized earth walls at the abutments. Weak upper soil conditions presented a challenge for the foundation design. Wilson made in-depth foundation studies and provided three foundation alternates. This effort included extensive lateral load modeling and analysis of large diameter (8-foot) drilled shafts using the COM624 computer program. The analysis included variable column stiffnesses to account for the pier arch shape.