Condeep
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 approach, stabilised by self-weight, enabled simplified installation and reduced seabed intervention, principles that remain highly relevant for today's offshore 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 associated with the deepwater Troll field. The concrete GBS stands directly on the seabed, stabilised by its own weight.
The solution ensures safe operation in harsh conditions while offering extremely large gas processing capacity. Concrete skirts penetrate the seabed, securing the foundation and eliminating the need for piles 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 long-term performance in harsh North Sea conditions.