Southgate Drive Interchange

Location Blacksburg, VA


Duration June 2015 – July 2017

This $8.8M project included the construction of two bridges on Southgate Drive over US 460 and three precast box culverts.

The existing U.S. Route 460 Bypass/Southgate Drive was a signalized T-intersection at the primary entrance to Virginia Tech’s Blacksburg campus. This intersection was eliminated and a new, diverging diamond interchange was constructed in a different location to accommodate current and anticipated traffic volumes. It established the northeastern terminus of the future U.S. Route 460/Route 685 Connector providing a new gateway entrance to Virginia Tech. It also allows for other roadway and shared use path relocations and connections for future improvements.

Key Challenges & Project Details

  • One box culvert had very unusual geologic conditions that required extensive studies to determine the best foundation support system.
  • Karst geologic conditions created foundation construction challenges for Wagman’s construction team with rock elevations varying significantly in every foundation.
  • FUN FACTS
    • The existing traffic signal is currently the only signal between the I-81 interchange in the Town of Christiansburg and the Town of Narrows in Giles County.
    • Form liners to create man made “Hokie Stone” on the bridges over US 460 were molded from original Hokie Stone buildings on the Virginia Tech Campus.
    • The new interchange required the relocation of Virginia Tech’s College of Agriculture working Dairy Farm. The dairy cows couldn’t initially be moved because the new farm did not have a fast enough internet connection. Each cow is embedded with a computer chip and WiFi connectivity to track food intake, milk production and activity patterns.