Troll A – The original concrete gravity‑based structure
Troll A is a monumental offshore natural gas platform in the North Sea and the original Condeep gravity‑based structure (GBS). This seabed‑founded, self-weight design demonstrated how concrete enables deepwater stability. Its principles of simplified offshore installation and reduced seabed intervention remain highly relevant for today’s developments.
Condeep is born - Breaking records on Troll A
- Location: North Sea, offshore Norway
- Project period: 1991–1996
- Client / Operator: Statoil (now Equinor)
- Structure type: Concrete gravity-based structure (Condeep)
Troll A addressed the extreme engineering challenges of the Troll field with a “Condeep” concrete substructure founded directly on the seabed by its own weight. The solution delivers deepwater stability in harsh North Sea conditions and supports very large gas processing capacity. Concrete skirts penetrate the seabed to secure the foundation, eliminating the need for piling or complex anchoring systems.
- Total height ~472 m
- Water depth ~300 m
- Concrete volume ~245,000 m³
- Reinforcing steel ~100,000 tonnes
- Weight (unballasted) ~683,600 tonnes
- Weight (operational) >1.2 million tonnes
- Original Condeep design setting the benchmark for offshore GBS platforms.
- Demonstrates unmatched scale, robustness and durability of concrete structures.
- Proven longterm performance in harsh North Sea conditions.