When the Virginia Department of Transportation was looking for a design-build team for its Route 460 connector project, they selected ours. As the engineer responsible for overall project design and substructure design in particular, we’re helping to provide a link between US Route 460 improvements in Kentucky and Virginia’s Coalfields Expressway. The mountainous terrain adds much complexity to the mile long project. The remote location makes it difficult to procure materials for what will be the tallest bridges in Virginia, measuring over 250 feet high and 1,700 feet long. In addition, there is more than 400 feet of vertical elevation differential to deal with, as well as coal seams at several piers, and the Pine Mountain Thrust Fault directly beneath two piers.
To address this, we designed the bridges to feature two PC I-beam approach spans and a four-span segmental concrete box girder unit with main spans of 489 feet and box girder depths of 31 feet at the continuous piers. The substructures consist of unique H-column piers with heights up to 230 feet. Both stub abutments on rock and MSE wall faced pile end bents are required at each end to accommodate the side-hill landing of the bridge.
The twin bridges were named the No. 1 bridge project in Roads & Bridges magazine's 2013 Top 10 Bridges program.