LOUDOUN COUNTY, VA
Northstar Boulevard, Phase II
CONNECTING TRAVELERS TO PLACES IN LOUDOUN COUNTY AND BEYOND
J2 provided preliminary and final designs for roadway improvements consisting of 4,100 linear feet of new alignment, 1,900 linear feet of roadway widening, turn lanes at three intersections, and a 40-foot-wide depressed grass median. The design included 10-foot-wide shared-use paths on both sides of the road. The project includes plans to install traffic signals with pedestrian controls at the Route 50 and Tall Cedars Parkway intersections.
J2, working with the Loudoun County Floodplain Team, updated the existing model to correct the flow location and provide analysis approved by Loudoun County, VDOT, and FEMA with a CLOMR. J2 modeled multiple bridge options and provided a design that limits the flood elevation rise and minimized the bridge length. The final design reduced the multi-span bridge to a 150-foot single-span bridge resulting in considerable project savings and permit impacts.
The roadway alignment crossed the South Fork of Broad Run Major Floodplain at a 45-degree skew requiring a 480-foot multi-span bridge. J2 discovered the 100-year flow distribution at the crossing was located incorrectly within the model resulting in an increased 100-year flow by about 600 cubic feet per second at the crossing and a larger structure.