Hallen Construction has recently completed the installation of a 30" steel gas transmission main for National Grid in Brooklyn, NY. On April 21, 2012, 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 direction 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 has now begun work on tying this new line into National Grid's existing transmission infrastructure and it is expected to be in service by the early summer.
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