GAS TRANSMISSION MAIN

Project Details

Location: Brooklyn, NY

HDD under the Belt Parkway Interchange with Flatbush Avenue with 2,900 linear feet of 30” x 0.75” wall Steel Gas Main.

Contractor: Network Infrastructure Inc.

Ken Walsh; (516) 385-3030

Customer: National Grid

Equipment Used: American Augers DD-625

Original Cost: $2,470,000.00

Final Cost: $2,470,000.00

Start Date: April 14, 2014

Completion Date: June 27, 2014

Conditions: subsurface conditions consisted of 20’ thick fine sand layer on a 30’ thick layer of organic peat with an underlying layer of dense sand and gravel

Challenges: The 30” Steel Main crossed under the Belt Parkway and Flatbush Ave butterfly interchange. The crossing reached a depth of 93 feet below entry. The 30” Gas Main had to be completely welded and hydro-tested before we could pull it. There were nine cranes and 35 stationary rollers used to support the pipe during the pull back. The single largest challenge was to preassemble the pipe string of 3,100 feet with the restriction of not being able to block any driveways or streets in Brooklyn, NY. The pipe string weighed 580,000 lbs when assembled and it had to be held 83 feet off the ground at the apex of the curve to avoid damaging the protective coating on the pipe.