An Algorithm for the Probabilistic Risk Calculation of Dropped Objects: Application of the Pipeline Protection System of Offshore Platforms

Dropped objects from cranes are one of the most hazardous events during the operation of the topside of offshore plants along with hydrocarbon gas explosion and fire. Although it is strongly suggested by international rules and regulations to evaluate probabilistic impact risk from dropped objects in the offshore industry, most engineers have had difficulties in estimating a reliable risk value because there is no concrete guideline on probabilistic impact risk analysis. Therefore, an algorithm to compute a reasonable probability of structural failure is proposed in this paper. Nonlinear transient finite element structural analyses for a 3D pipeline protection system on a topside module are carried out using LS-DYNA in order to get structural responses for each of the selected dropped object scenarios.