Jacket design to resist ship impact

The response of three jacket structures is investigated under accidental sh ip impact. Fully non-linear finite element analysis results agree well with the predictions of a locally non-linear beam-column model attached to an e lastic structure. The results suggest that typical North Sea jackets in mod erate water depth and carrying moderately large topsides may be able to res ist very high impact energies. For very light jackets, however, sudden over all collapse is possible, particularly under nodal impact. The criticality of ship impact for jacket design is very dependent on the relative magnitud es of the loads at which the ship and the jacket collapse. The topside conf iguration is also important as it determines the manner in which tension lo ads generated during the impact are redistributed through the structure.