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US 460 Grassy Creek Segmental Bridge Design-Build

The Virginia Department of Transportation¡¯s (VDOT) Route 460 connector project aimed to provide a link between US Route 460 improvements in Kentucky and Virginia¡¯s Coalfields Expressway. We supported VDOT as the engineer responsible for overall project design and substructure design. The mountainous terrain added complexity to the mile-long project, while the remote location made it difficult to procure materials for the tallest bridges in Virginia, measuring over 250 feet high and 1,700 feet long. In addition, there was 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.

The designed twin bridge featured 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.

Stantec¡¯s additional responsibilities included performing an independent review of the post-tensioned segmental superstructure design and plans and performing a load rating analysis for the as-built condition of the superstructure.?