Tower of power
Pumpcrete draws upon technology and previous experience to create massive concrete gravity structure Grave situation
The West White Rose Project features a huge concrete structure that is taking shape. Once joined with its wellhead platform, it will be extracting oil and gas for owners Husky Energy off the coast of Newfoundland. With the upper base caisson sections completed, the lower caissons are made ready for construction. For these operations, roughly 300 metres of five-inch pipe were used to feed the placing booms. Construction of an additional 100-metre-tall conical section will follow.
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ention construction of an offshore oil platform and visions of a rig destined for the Middle East, the Gulf of Mexico, or the North Sea probably come to mind. However, in the industrial seaport of Argentia, Newfoundland, a huge concrete structure is taking shape that, once joined with its wellhead platform, will be extracting oil and gas for owners Husky Energy some 350 kilometres off that very same Newfoundland coast. Heading up the concrete pumping facet of the West White Rose Project, as
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Canadian Concrete Pumper 2020
it is known, Canadian firm Pumpcrete is using a pair of placing booms and a slipform system to help make that happen. By project’s end, the company will have pumped more than 78,000 cubic metres (102,000 cubic yards) of concrete, and the structure will rise to a height of 146 metres (480 feet). A small fleet of tugs will then tow it to its designated location in the Atlantic, where a combination of water and ballast will allow it to take its place, rising up off the ocean floor awaiting attachment of the deck and the start of production.
Work on the West White Rose Project’s concrete gravity structure (CGS) is being conducted in a purpose-built graving dock which — testimony to the size of the CGS itself — measures 110-metresby-130-metres (at the base with a 1:1 slope) by 25-metres deep. When work is complete, the dock will be flooded to allow the structure to float, and an earthen berm will be removed, opening the dock to the port for movement of the completed structure. According to Dave Moriarty, Pumpcrete’s special projects manager, work on the CGS began with the mass pour of a 75-metre diameter, 1.2-metre-thick base slab. “This was really the most basic part of the entire project,” said Moriarty. “Other than the incredible amount of rebar extending from it, the slab was a basic 13,000-cubic-metre pour using a pair of Schwing SP 8800-E stationary pumps feeding Schwing SDB 35 placing booms seated atop octagonal masts. The combination of the 35-metre booms and the masts themselves — a pair of six-metre sections joined to give us 12 metres of height — afforded us all the reach we needed. We poured the slab in five separate sections: the centre and four quadrants, and did it in 400-millimetre lifts.” Seawater ballasting pipework was also cast into the base slab to allow the CGS, when completed, to be flooded, towed, and ballasted to install it in position on the Grand Banks southeast of Newfoundland.
Giving them the slip With the base slab completed, Moriarty said they moved on to the base caissons which rise from the surface of the slab upward for 46 metres. Each of the hollow caisson sections has 500-millimetre-thick
