Ice-induced vibrations of offshore structures - Looking beyond ISO 19906

Abstract

The paper deals with the classical ice engineering challenge of ice-induced vibrations (IIV) of offshore platforms. There is still a general industry concern with aspects of IIV and the load amplification that can arise in some situations resulting from ice interaction with a structure. It was thought important to re-visit current design methodology and practice, as well as the data that led to their formulation. A joint industry project (JIP) was organized, in which the main offshore oil companies joined together to sponsor development and validation of models for ice induced vibration. Broadly, the JIP: i) identified interesting aspects of the mechanisms behind IIV; ii) sponsored further development of three numerical modeling approaches chosen for the range of physics they captured; iii) and, provided calibrated models to an independent engineering company who used them to assess the model's accuracy in simulating five full-scale events whose data had been withheld from the model developers - ensuring an independent validation rather than a further fitting of models to data. This paper is a "briefing" and provides an overview of the background, progress, and some validation findings: a status report on the reliability of present procedures available to the offshore industry when designing platforms in moving ice where IIV can be expected. The "science" behind the models will be presented by the model developers themselves (e.g. Hendrikse & Metrikine, 2013) and in further publications once the JIP confidentiality conditions expire.