Bergen Point Southwest Outfall Replacement

OHLA USA, in a joint venture, carried out the Bergen Point Outfall Replacement contract, which called for the construction of a tunnel 113 feet beneath the Great South Bay onLong Island.  The tunnel houses an existing treated water outfall system that runs from the Bergen Point WaterTreatment Plant and connects to the Barrier Island. The tunnel measures 2.6miles and has a diameter of ten feet. 

A ground-freezing technique was used to construct the TBM entry and exit shafts, which extend to a depth of 80 to 100 feet below grade. The sophisticated mechanics on the TBM simultaneously allowed for the installation of48-inch-wide precast concrete segments onto the top and bottom of the newly excavated tunnel. The precast segment rings cover the entire length of the tunnel and securely hold the structure in place.