The Troll A platform

The Troll A offshore natural gas platform in the Troll gas field off the west coast of Norway has an amazing claim to fame.

It is the largest object ever moved by mankind relative to the surface of the earth.

With 1.2 million tons ballasted under tow, 472 meters high, with underwater concrete structure at 369 meters, and dry weight of 656,000 tons, the Troll A platform is an engineering marvel.

The platform stands on the sea floor 303 meters below the surface of the sea and one of the concrete cylindrical legs has an elevator that takes over nine minutes to travel from the platform above the waves to the sea floor.

The walls of Troll A’s legs are over 1 meter thick made of steel reinforced concrete that was formed in one continuous pour.

Normally a platform’s legs are transported on their side and then – supported by flotation devices – are dropped into place.

In the case of Troll A, however, the whole platform was assembled in one location, and then floated out to sea. The Troll platform was towed over 200 kilometers from Vats, in the northern part of Rogaland, to the Troll field.

The tow took a total of seven days.

The platform  is currently operated by Statoil.


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