Reliability Study of a North-Sea Jack-Up Under Action of Wave-in-Deck, SH- and SV-Seismic Waves Considering Spud-Can-Soil Interaction

In the current study, the effect of spud-can-soil interaction modeling as well as wave load modeling and sea-state on the reliability index of a three-leg North-sea drilling type jack-up platform is studied. The platform has operated in depths of 95–105m and its three main legs modeled as pipe elements and the main deck is also modeled using general beam and also shell/plate elements. The spud-can foundation is modeled using elasto-plastic, hyper-elastic springs as well as spud-model of usfos using a general non-associative plasticity model. The wave-in-deck load is considered using API-RP2A [1], Shell and Statoil models. The SH and SV-seismic waves are considered separately at spud-can base as scaled. The preliminary results of this study showed that the annual probability of failure for the Jack-up platform is significantly affected by the random-sea and wave-in-deck modeling as well as spud-can-soil interaction modeling and soil parameters. Study of importance factors indicated that more refined spud-can-soil interaction modeling as well as wave-in-deck load modeling might improve the calculation models and hence reduce their associated uncertainty in reliability analysis of jack-up type platform.