Non-linear structural analysis for in-situ platform demolition

The abandonment of offshore platforms is an interesting engineering field, both regarding the operating methodologies connected with technological aspects, and for the structural aspects during the decommission-ing phases. Specific abandonment plans must be studied for every installation in order to assure the safety ofthe identified decommissioning sequence. The structural analyses proposed in the present paper for the pro-posed decommissioning sequence, are in a non-linear field and they show how it is possible with a proposedsequence to obtain two important results: firstly to reduces the times for underwater cutting operations and,secondly, to assure a sufficient safety margin during the cutting operations.This paper becomes part in the tradition of studies inherent the offshore platforms decommissioning, propos-ing one preferred abandonment methodology for the steel jacket platforms, carried out by cutting the struc-tural members, in a safe sequence.