Teams set up the 5,700-ft-long area of pipeline under the Newport News shipping channel in the James River in an operation that lasted more than a day.
Picture courtesy Garney Construction
A group dealing with the Hampton Roads Sanitation District’s Boat Harbor Treatment Plant Conversion and Transmission program reached a turning point in May when they finished the setup of more than 5,700 feet of big bore pipeline under the Newport News shipping channel in the James River in a constant pipepull operation that lasted more than 24 hours.
The 42-in.-dia DR11 HDPE pipeline will become part of a wastewater force primary linking from a brand-new pumping station being constructed on the Newport News, Va., side of the river to the sanitation district (HRSD)’s Nansemond Treatment Plant in Suffolk, Va. To install it, the group utilized horizontal directional drilling.
The group initially prepared for a water-to-water directional drill of about 4,000 feet, however understood they might get rid of among the water platforms by extending the drill, states Paul Longo, senior partner and senior task supervisor at Dewberry, the lead engineer for the undersea transmission pipeline setup.
“Extending it would include practically a half-mile of drill length and would press the limitations of the product, the drilling operations, the mud managing systems– truly the limitations of the trenchless setup market for this specific pipeline at such big size and being HDPE,” he states.
The group– which likewise consists of specialist Garney Construction; Huxted Trenchless, which carried out the drill; Brierley Associates, which dealt with the geotechnical and trenchless style; and Seaward Marine, which supplied stack and platform setup– identified what they would require to make the longer pipepull work. The group carried out additional geotechnical examinations and invested 7 days carrying out a pilot drill to confirm conditions under the river.
“That provided us self-confidence in the capability to in fact go through with the execution and make it eventually effective,” states Jordan Carrier, executive vice president of pipeline east at Garney.
While steel pipeline would have had a greater safe allowed pull force, the group required to utilize HDPE due to the destructive marine environment. They discovered a HDPE pipeline maker in Texas, Performance Pipe, that had the ability to fulfill their requirements for ovality tolerances and capability to manage external loads. The group likewise utilized a pipeline pusher from German-based devices producer Prime Drilling that was custom-made for big size HDPE. The preparation on sourcing the pipeline pusher was upwards of a year, Carrier states.
The group’s work platform on the river housed the pipeline pusher, and they placed the pipeline through it prior to draw back to enable it to travel through easily or with extra compression. They were then able to utilize the pipeline pusher to include compression to the back and alleviate the stress from pulling, Longo states.
“We’re talking 5,700 feet of pipeline,” Longo states. “You can’t even see completion of it.”
Teams threaded the pipeline through devices from a platform on the river.