ISUM for Offshore Frame Structures

Abstract

The paper presents the background and major ideas behind the computer program USFOS. The program is today widely used by the offshore industry to assess the resistance of oil and gas installations against abnormal environmental loads and accidental actions, such as ship collisions, fires and explosions. The assessment is normally performed in the accidental limit states; i.e. substantial yielding, buckling, partial collapse may take place, but the structure should maintain overall integrity. The features and concepts and models adopted in USFOS have also proved to be very useful in the analysis of totally different edifices. A few examples of this are given in the paper.