Replacement of Existing Water Siphons

OHLA USA, Inc., along with its subsidiary, Judlau Contracting, Inc., performed the work required to install new potable water transmission siphons contained within a new 9,500-foot-long tunnel located more than 100 feet below New York Harbor. In order to execute the work, workers constructed shafts at sites in Brooklyn and Staten Island, which was followed by the tunnel work, which called for the excavation of rock and sand materials using an advanced pressure balance tunnel boring machine (TBM) to house the 9,440-linear-foot, 72-inch steel water main. While excavation was ongoing, the TBM lined the 12’4-inch diameter tunnel with concrete rings on 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. This was followed by the installation of 3,900 linear feet of water transmission mains (48”-72” diameter), 3,200 linear feet of new distribution water mains, two 84” micro-tunnels (310’ & 165’ long), 10,500 linear feet of mini-pile supports, and 900 feet of sewer replacements (36” – 72” diameter). Additionally, workers constructed a 3,000-square-foot chlorination building and other related infrastructure improvements.