Known collectively as “Route 29 Solutions”, Charlottesville’s eight highway improvement projects represent a six-year effort by VDOT to reduce congestion on the Route 29 corridor. Schnabel has served as the geotechnical engineer on four of the eight projects, three of them with RK&K. One of the most challenging projects, The Rio Road grade separation, involved the depression of Route 29’s four inner lanes along a 1,400-foot-long section, to allow for the overhead passage of Rio Road. Retaining walls up to 23 feet high flank this section, which is part of a highly congested interchange. Schnabel was faced with a hyper-accelerated schedule for both design and construction.

The design-build team had only five weeks to complete the entire design, and construction had to occur within the 103-day period when the University of Virginia was not in session.

Schnabel’s team designed the bridge section and entire retaining wall system for the depressed roadway. To meet the demanding schedule, the team devised a “top-down” construction scheme that allowed for the installation of soldier piles and tiebacks from the ground surface and abutment walls, using the bridge as a lateral brace. This approach struck the 23-foot-high cantilevered wall from the equation. It also eliminated the need to install multiple levels of bracing at night with traffic control ­– a feat not likely to be achievable during the closeout phase.

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