Structural risk evaluation for offshore platforms under major accidental events

A structural risk evaluation methodology is introduced in this paper for the offshore platforms against major hazard events (hurricanes and earthquakes) during the operating life of the platforms. The primary objective is to evaluate the risk level from the major hazard events to identify possible risk reduction solutions. Firstly a non-linear progressive collapse analysis approach is presented to investigate the platform capacity to resist the loads imposed by major hazard events. The structural reliability method is then proposed to estimate the probability of platform failure under major hazard events. The platform failure limit state function is defined in terms of hazard loads and platform capacity. Uncertainties are included in the parameters associated with hazard loads and platform capacity. Finally the platform failure consequence and the probability of platform failure are combined to determine the platform risk associated with the major hazard events. Case studies are presented to illustrate the application of the developed structural risk evaluation approach.