Collisions and Damage of Offshore Structures: A State-of-the-Art

Abstract

Over the recent years, following the very rapid increase in the construction and installation of offshore structures, there has been a considerable growth of interest in the assessment of the probabilities and consequences of collision and damage of such structures. This is reflected by the very large number of papers published over the last 15 yr and the multitude of conferences and meetings held on the subject. Many research programs have been completed or are in progress at many centers and institutions over the world. Accidental loading and damage are now accepted design parameters recommended for consideration in a number of Codes for the design in offshore structures. This paper reviews the state-of-the-art with respect to the probabilities and consequences of collisions and accidental loading in general, and methods for the assessment of the design of steel offshore structures against damage. Most of the available information in the field of offshore collisions and accidental loading emanates from research and experience related to ship safety. However, in this paper emphasis is placed on research activity and available information concerned with offshore structures, such as platforms, semisubmersibles, etc. There is a considerable amount of information available on methods for evaluating the extent and effects on damage of these structures and in estimating their residual strength in the damaged condition. As this is an area currently of major interest in the offshore industry, the paper presents comprehensive information and some new results relating to all major structural components. The state-of-the-art with regards to methods and principles for design against damage is also reviewed and commented upon. The paper concludes with general recommendations and indications of areas where future research could be most usefully directed.