In my last blog, I discussed the ins and outs of conducting a routing study on the underground substations for the electrical power system at the University of Virginia (UVA), which was the first of three phases, including routing, design, and construction. After months of research, interviews, and analysis, phase one was complete. We started with nearly 40 possible ductbank routes—a pathway containing multiple conduits that enclose electrical wires so the electrical system can be placed underground, keeping it safe from weather-related obstructions—and whittled our way down to one that will revolutionize power reliability for the university.

With the preferred route selected, we were able to move on to creating a detailed design—phase two. In its entirety, the new underground ductbank will stretch across three miles of the community. It will require 14 miles of polyvinyl chloride (PVC) conduit encased in concrete and 33 underground vaults, each measuring up to eight feet wide, eight feet tall, and 16 feet long. The new underground service is expected to increase power reliability by more than 90 percent.

Using Advanced Lidar Technology

The design phase began in the winter of 2016 and included a topographic survey of the entire route, utilizing a truck-mounted 3-D laser scanner. This method was selected based on the fact that the preferred route was mostly located along active roadways. As compared to traditional survey methods, this technique enabled us to speed up the data acquisition process, reduce risks to survey personnel working on these roadways, and minimize negative impacts to the motoring public.

Utilizing Multiple Construction Methods

The majority of the project was scheduled to be installed by way of open trench excavation, however, there were certain key points where trenchless technology was required. One of those locations was along Fontaine Avenue, which sits several hundred feet from an active fire station. As a result, we were unable to block any part of the road without affecting response time for the fire department. In order to accommodate this restriction, we are utilizing the jack and bore method—a horizontal boring technique—to install a steel casing pipe under the roadway. Conduits are also being installed in steel casing pipe from the side of the road.

An Enriching Project

Now that we’re in the construction phase, it’s exciting to see the design pan out just as we’d intended. Having worked with UVA for nearly 10 years now, I feel a connection to this project and I’m proud to say that I’ve been a part of something transformative for a university that’s enriching the lives of so many others.

UNIVERSITY OF VIRGINIA 35kV DUCTBANK