This paper presents a discussion of methods by which typical North sea piled, steel production platforms may be examined to establish their behaviour in the event of an accident sufficient to cause structural damage.

Types of possible damage are presented in this paper. They might be caused by an explosion, by the dropping of large objects, the rupture of a gas riser causing a hydrocarbon jet fire (high intensity fire) or, in the case of an oil riser, a pool fire (lower intensity fire).

Damage may occur to any of the primary components that comprise a production platform, namely the jacket, cellar deck (or MSF), or modules. The broad findings from a study of a typical platform are presented together with a discussion of the salient results and conclusions.

To analyse separate parts of a platform, whether modules alone, jacket alone, or combinations of structures that comprise the platform, it is beneficial to carry out a nonlinear, progressive collapse analysis. Applied loads are increased from zero to some predetermined level, and the behaviour of the damaged structure monitored for each loading increment. Such an analysis would predict the initial failure of members and introduce one, two or three hinges per member as loads are increased. It would account for P - delta effects associated with large deflections and would fully account for load and moment redistribution as members form three-hinge mechanisms.

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