Skip to main content

Manning Drive Steam Tunnel, Phase 2B


Clancy & Theys Construction Company provided general contracting inbuilding the Manning Drive Steam Tunnel, Phase 2B. The project was a 1/3 mile long utility tunnel that began near Kenan Stadium headed south under Emergency and Manning Drives, and half-way down Hibbard Drive where it connected to the Phase I tunnel already in operation.  The work involved excavation of a soil-nailed or piled and lagged trench 23 feet deep and 20 feet wide, with three wider nodes for distribution vaults that were as big as 46,000 cubic feet.  The tunnel system is typically 9 feet x 9 feet clear inside and carries up to 42 inches chilled water lines and 24 inches steam lines supported on structural steel racks.  Outside the tunnel, 48 conduit duct banks were run for 100 KVA and 15 KVA power, plus telecommunications ducts for fiber optics.  Parallel with the tunnel is a 12-inch domestic water line, a 24-inch re-use water line, and storm sewers.  A 450-foot storm line, 72 foot in diameter with five large manholes, was added to solve a long-standing flooding problem for the 65 acres that drained toward this excavation.  This project tied into both ends of a new steam plant, and had two shallow steam tunnels radiating out from two of the vaults.  Clancy & Theys also constructed an emergency boiler plant, which was brought on line in two months to serve as emergency heating back-up for half of the campus.

The project also included all pedestrian and vehicular traffic modifications with associated protection, piping, fencing, landscaping, tunnel waterproofing, tunnel conduits, and pavement markings.

Project Details
Location: Chapel Hill, North Carolina
Size: 1/3 mile
Share this project: