Route 7 and Battlefield Parkway Interchange

To combat congestion on the heavily traveled roads of Leesburg, Virginia, the city launched a $59 million project for the construction of a single-point urban interchange. Administered through the Virginia Department of Transportation, the project called for a two-span bridge to carry Battlefield Parkway over Route 7. Other improvements included Route 7 lane widening, MSE walls, culvert replacements, new signals and signs, and stormwater management. Geotechnical conditions posed challenges. Schnabel had the solution.

Wagman served as the design builder for the highly involved design-build project. Schnabel provided geotechnical and pavement engineering services to Parsons, who was the prime engineer. Subsurface exploration was performed by Schnabel’s subcontractor, Connelly and Associates, Inc., and included test borings to categorize and explore the extent of diabase rock intrusions and unsuitable “blackjack” clays. Analyses were conducted to determine the settlement and stability of slopes and embankments, axial and lateral pile capacities, shallow  foundations, and pavement designs. Multiple geotechnical engineering reports were provided to facilitate the expedited project schedule.

Geotechnical project challenges included extreme hardness and variability of the diabase rock at the bridge foundation locations. Schnabel provided both driven and alternative rock-socketed pile foundation details to be used if the piles could not be advanced to the minimum embedment depth. Schnabel representatives were on site to field engineer rock socket lengths based on the pile-specific field conditions. This allowed for the installation of the piles in an expedited fashion – and ensured confidence in the performance of the foundation system. The projected earned numerous awards, including the DBIA Honor Award, ACEC MW Grand Pinnacle Award, and Engineering News Record (ENR) Mid-Atlantic Best Project, Award of Merit.