Big Deal. Platforms are part of a $10 billion investment. photo courtesy of Hans Hitz/Schwager Davis Inc. |
...similar platforms, Lunskoyes is slightly bigger, rising from a 13.5-m-tall, 105x88-m base with 124 cells. From this base, four legs rise nearly 52 m with diameters of about 25 m.
They "entailed the most complex geometries ever achieved by...slipform," notes Vinzenz Fuchs, project manager of subcontractor Gleitbau GmbH, Salzburg, Austria. The main shafts inclinations shifted from 20° to vertical. And at localized blisters, wall thicknesses vary from 70 cm to 2.15 m.
The platforms Finnish main civil engineering contractor, Espoo-based Quattrogemini Ltd., is a minnow by world standards but has a decade of experience in Russia. It teamed up with a veteran Norwegian platform designer to bid for the contract in late 2002, says chief executive Lasse Alanne.
Quattrogemini and Aker Kvaerner Technology A.S., Stavanger, Norway, bid on a lump-sum and cost-plus basis in late 2002 and won the next February. Because no full front-end engineering design had been done, uncertainties boosted the lump-sum price, says Alanne. So SEIL went for the cost-plus option, but included a fixed element for expatriates costs.
Holding Tight. Schedule was met despite major changes in design. photo courtesy of Hans Hitz/Schwager Davis Inc. |
SEIL signed contracts worth $250 million with Quattrogemini and Aker Kvaerner to design and built both platforms in July 2003. The Finnish mechanical outfitting firm RROffshore Oy joined the integrated team and a division of Kvaerner secured the contract to deliver the platforms. The global cost of all that is estimated at about $600 million.
From Alannes viewpoint, the project "started at zero," without even a soil survey for the new dry dock. He was alarmed "that the permits to build the structures were not in place," he adds.
To accelerate dock excavation, starting in August 2003, the contractor imported large dump trucks instead of using the planned smaller machines. And it added a shift, going to non-stop working.
Big specification changes then played havoc with designs. With increasing seismic parameters, for example, pipe movement in the legs went from 15 cm to 75 cm. Dealing with change orders "became a battle," says Alanne. "We are talking about double the amount of rebar."
With shifting designs, "we had to change our [formwork] adjustment lists ...many times," says Fuchs. "It was necessary to produce 1,000 pages...of adjustment lists for one [leg] and we had eight shafts."
Workers peaked at about 2,500, mainly Russians, with 1,500 on Quattrogeminis payroll, says Alanne. His team handled most construction directly, hiring Gleitbau to supply and manage the slipforming system and Schwager Davis Inc., San Jose, Calif., to handle post-tensioning.
Gleitbau began slipping 61,900 cu m of concrete in May of last year, finishing late this January, two days early, notes Fuchs. SDI finished 12 months of post-tensioning this May, ahead of schedule with "zero accidents" and no broken strands, says project manager Hans Hitz.
"The time schedule has been kept," says Alanne. "Of course, there has been an increase in cost." His satisfaction is tempered by the projects one accidental death. It happened in the last few weeks after eight million hours of work.
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