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In the foreground, the Topsides rests on the assembly pier at Bull Arm. In the background, floating at its deepwter site, is the Gravity Base Stucture. The photo was taken early in 1997, when construction was essentially complete. |
| Construction of the Hibernia Gravity Base Structure (GBS) and assembly of the Topsides and associated Topsides-mounted structures occurred in Bull Arm, Trinity Bay, Newfoundland. Prior to the Hibernia project, Bull Arm was a "greenfield" site with little local supporting infrastructure. Located less than 150 km from St. John's, the site is ideally situated to accommodate construction of a gravity base platform. Steep hills provided excellent protection for drydock construction while a near-shore deepwater construction site accommodated final GBS construction and GBS-to-Topsides mating. |
 A giant concrete boat, the completed GBS floats in the waters of Bull Arm. |
In October of 1990, using owner capital and grants funded by the federal and provincial governments, a world class drydock and fabrication facility were built. Some features of the site include:
- The largest rebar shop in North America
- onshore concrete batch plant
- wharfage
- 150 metre long by 50 metre high assembly hall
- blast/ paint shop
- pipe shop
- associated cutting and carpentry shops
- permanent office building.
 The completed Topsides sits on the assembly pier at Bull Arm. |
During peak construction in 1995, roughly 5,800 people were employed at the site. To house, feed and entertain the workers, a self-contained community was created that included:
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| Gravity Base Structure (GBS) Delays to construction occurred as a result of the ground-breaking design of the GBS. In April 1994, the project announced that construction of the platform was over budget, and the first oil start-up date was delayed by five months to December 1997. At that time, new contractors were added to the GBS construction team and the method of pouring concrete was changed from jump-forming to slip-forming, a continuous process of installing reinforcing steel and pouring concrete. From that point, every major GBS milestone was achieved on schedule and within budget. Construction of the GBS was completed on November 1, 1996. |
 During the mating operation, the GBS was ballasted (by pumping water into its storage cells) until the tops of the support shafts were projecting just a few metres from the water. |
 The Topsides was lifted off the assembly pier by two giant barges and towed over the submerged GBS, which then deballasted and rose to meet the Topsides, eventually lifting it clear of the barges. The two pieces had become one! |
Topsides One Topsides supermodule, the Wellhead Module, was fabricated at Bull Arm along with four Topsides-mounted structures: the flareboom, helideck, and main and auxiliary lifeboat stations. The remaining components were fabricated in construction sites located around the world and transported to Newfoundland for final assembly and hook-up at Bull Arm. On February 27, 1997, the 37,000-tonne Topsides was lifted from its assembly pier by two giant barges, then floated to the middle of Bull Arm and mated with the 550,000 tonne Gravity Base Structure (GBS) to form one integrated unit. Tow-out of the platform began on May 23, 1997. It was installed at its permanent location on the Grand Banks on June 5, to within one metre of the target contact point on the ocean floor. The first well began drilling on July 28, 19 days ahead of schedule, and First Oil was achieved on November 17, 1997, a full four weeks ahead of schedule. |
 The tow-out of the Hibernia Platform began on May 23,1997. In the top left corner, the platform support vessel Maersk Nascopie can be seen towing a small iceberg. |
 In all, nine of the world's largest tugboats were involved in the tow-out operation. |
At the end of construction, ownership of the site was transferred to the provincial government, and it is leased to PCL Industrial Constructors who are doing fabrication work on the Terra Nova development.
