An approximately four-mile-long, 18-ft-diameter and 200-ft-deep tunnel to mitigate storm water and combined sewer overflow into the Connecticut River and Long Island Sound is slated to begin construction this month.
Granite Construction Inc. subsidiary Kenny Construction Co. of Northbrook, Ill., and Japan’s Obayashi Corp. recently won the $279-million contract for the South Hartford Conveyance and Storage Tunnel. The joint-venture team will construct a launch shaft, a retrieval shaft, a pump-station excavation shaft, seven drop shafts, seven adits with deaeration chambers and an odor-control building at the retrieval shaft. Running from West Hartford, Conn., to the Hartford Water Pollution Control Facility, the 41.5-million-gallon-capacity tunnel is critical to the metropolitan district’s 20-year clean-water initiative to mitigate combined sewer overflows in the greater Hartford region.
Because it can moderate the damaging effects of earthquakes, base-isolation is a technique used primarily in seismically active regions. ENR takes a look at some of the largest applications of base-isolation technologies in the world.