NORRIS CUT 60-INCH FORCE MAIN/MICRO-TUNNEL
Miami-Dade Water and Sewer Department
The Miami-Dade Water and Sewer Department (MDWASD) Norris Cut 60″ Force Main/Micro-Tunnel is a design-build project consisting of 5,300 linear feet of 90-inch-diameter precast concrete tunnel, with a 60-inch diameter HOBAS carrier pipe inside. Woolpert is the lead pipe design engineer on the project. Once installation is complete, the annular space between the tunnel and carrier pipe will be grouted with cellular concrete.
The tunnel will span from Fisher Island to the MDWASD Central District Waste Water Treatment Plant (WWTP) on Virginia Key. The planned tunnel will be installed 85 feet below sea level to accommodate shipping vessels through the channel.
Approximately 2,700 linear feet of 60-inch-diameter pre-stressed concrete cylinder pipe (PCCP) will be used in the open-cut portion of this project, which is within the WWTP site, and will be connected to an existing 54-inch-diameter PCCP near the plant headworks. This segment has been designed for 120 pounds per square inch, making the connection to the existing PCCP of extreme importance. The 60-inch-diameter PCCP will also be used within the shafts, leading to the tunnel.