Hallen Construction completed the installation of a 30″ steel gas transmission main for National Grid in Brooklyn, NY. After 6 weeks of preparation and nearly a month ahead of schedule, a pipeline was pulled under the ground and across Paerdegat Basin by using the directional drill method of trenchless installation.
Temporarily annexing traffic lanes along Seaview Avenue, 41 pieces of 40-foot long pipe were laid out and welded together to form one solid 1,640-foot pipeline. Once welded, the pipeline was positioned and placed on specially designed rollers to facilitate the monumental task of pulling the nearly 375,000-pound line from one end of the basin to the other. A vertical radius bend of 3,000 feet was realized giving the pipe its maximum depth of 40 feet below the waterway’s bottom. With all this, perhaps the most unique and challenging dynamic of the project was to overcome a considerable dog leg left turn along Seaview Ave. The pipe needed to be bent horizontally at a 2,000-foot radius in order to align itself into the entry pit and make its way home.
Hallen connected this line into National Grid’s existing transmission infrastructure.