Concrete Gravity Platforms

Abstract

Abstract Concrete gravity platforms are structures resting on the seabed. They must have sufficient weight to remain in place when subjected to waves, current, and wind. Their configuration in contact with the sea bottom must be adapted to the specific soil conditions at the site. At the time of this writing (2016), there were 50 major offshore concrete platforms for the oil and gas industry in the world, almost all of them of the gravity type. Offshore platforms are not built in situ , as most land‐based structures are, but are built somewhere else and towed to and installed at the site. This unique way of construction favors deep fiords that give sheltered construction sites and sufficient depth for construction. Building the topside structure and the concrete substructure simultaneously, and then mating the two in sheltered waters before towing the complete platform to site, saves valuable time. When fiords have not been available, concrete gravity platforms have also been constructed in a dry dock, and the topside is lift‐installed. Smaller structures may be built on barges.