Pumpcrete, Toronto, Canada, recorded the largest continuous pour, pumping the next construction phase of a gravity base structure (GBS) that will eventually provide the foundation for an oil well platform in the Atlantic Ocean. The 65,000-cubic-yard pour, conducted over 35 days at one kilometer offshore, is the largest continuous pour of its kind. The GBS under construction requires massive amounts of pumped concrete, with distribution choreographed by an automated system designed by Pumpcrete, including four Schwing SP 4800 stationary pumps and two Schwing SPB 35-meter placing booms.
The separate placing booms and stationary pumps provide an important connection to the slip forming of the central shaft and seven cells that make up the GBS. The structure is now at a deep water construction site where concrete batching and pumping continues from barges. As the forms rise, the four-section booms accommodate the movement. Flexible hoses on the end of the booms plug into the pipeline that feeds seven hoppers located on the three-tiered slip form system.
Located in the Atlantic coastal areas of Newfoundland and Labrador, the initial fabrication site was adjacent to a man-made earthen barrier that was removed to flood the construction site and float the gigantic structure into deep water. (See Concrete Pumping Magazine, winter 2014 issue.)
“Considering that the crew worked continuously over a month to pump 65,000 cubic yards in all weather conditions, speaks volumes about the equipment and dedication of the workers,” comments Dave Moriarty, pump manager for Pumpcrete.
The GBS will eventually reach a height of nearly 400 feet when the next phase of the slip forming takes place in deeper water. The final concrete tally, once the GBS is completed with a slip formed shaft to support the topside structure, will be 172,650 cubic yards. The 65,000-ton topside structure with offices, drilling equipment and accommodations for 200 workers is 520 by 210 feet, and will be floated over the GBS and attached before being towed to the Grand Banks, 217 miles from shore, where it will be sunk in 300 feet of water. Oil extraction is scheduled to begin in 2017.