Goal: Design an Internal Lifting Tool (ILT) that is capable of lifting 2000 metric tonnes for an offshore decommissioning project. The ILT has to be designed for gripping inside a jacket leg with a wall thickness of only 40 mm.
Result: The Internal Lifting Tool is designed for
gripping the inside of a jacket leg during an offshore decommissioning
project. The ILT distributes the lifting load effectively over a large
section of the jacket leg. This way a safe lift is guaranteed even
though the jacket leg wall is very thin.
Advanced non-linear FE calculations were made in order to proof that the ILT is fit for purpose. These calculations included all the vital parts of the ILT and a plastic material model of the pile.
Normal internal lifting tools are designed for lifting foundation piles. The wall thickness of these foundation piles is much larger than that of the jacket leg. Therefore this decommissioning ILT is provided with gripping elements that are much longer and wider than usual. This way the lifting load is distributed over a larger section of the jacket leg and decommissioning can take place in a safe way.
Client: IHC Handling Systems vof EN