Application of the suggested ice strength coefficients in ISO 19906 to intermittent crushing

For offshore wind turbines on monopile or jacket foundations without ice cones, one of the relevant design load cases is that of ice floes or level ice crushing against the structure resulting in ice-induced vibrations. In relation to that design load case, a relevant question is which ice strength coefficient to use in the crushing formula in...

Dynamic ice loads for offshore wind support structure design

For offshore wind farms which are planned in sub-arctic regions like the Baltic Sea and Bohai Bay, support structure design has to account for load effects from dynamic ice-structure interaction. There is relatively high uncertainty related to dynamic ice loads as little to no load- and response data of offshore wind turbines exposed to...

Development of Combined Load Spectra for Offshore Structures Subjected to Wind, Wave, and Ice Loading

Fixed offshore wind turbines continue to be developed for high latitude areas where not only wind and wave loads need to be considered but also moving sea ice. Current rules and regulations for the design of fixed offshore structures in ice-covered waters do not adequately consider the effects of ice loading and its stochastic nature on the...

Experimental study on ice-structure interaction phenomena of vertically sided structures

This study analyses the results from basin tests with a vertically sided cylindrical pile loaded by ice failing in crushing. Tests were performed with a ‘rigid’ structure and with structural models representing a series of single-degree-of-freedom (SDOF) oscillators covering a wide range of mass, frequency, and damping values. The structural...

Methodology for estimating offshore wind turbine fatigue life under combined loads of wind, waves and ice at sub-zero temperatures

Due to increasing trend of building offshore wind turbines (OWTs) in seas at high latitudes where seasonal sea ice occurs, novel methods for design of such structures are needed. Specifically, the effect of ice-induced vibrations (IIVs) on fatigue life of the structures is currently poorly understood. Therefore, the goal of this paper is to...

Dynamic response of an offshore structure interacting with an ice floe failing in crushing

Interaction of sea or lake ice with vertically sided offshore structures may result in severe structural vibrations commonly referred to as ice-induced vibrations. With the surge in offshore wind developments in sub-arctic regions this problem has received increased attention over the last decade, whereas traditionally the topic has been mainly...

On pressure modes in ice-induced vibrations using multivariate analysis

Pressures at the ice-structure interface during model-scale ice-structure interaction are often measured with tactile sensors. Resulting datasets usually include large volume of data along with some measurement error and noise; therefore, it is inherently hard to extract the hidden fluctuating pressures in the system. Identifying the...

A study of the transition ice speed from intermittent crushing to frequency lock-in vibrations based on model-scale experiments

For the design of offshore structures in regions with ice-infested waters, the prediction of interaction between ice floe and support structure is essential. If the structure is vertically sided at the ice-structure interface, then ice-induced vibrations can develop. Recently, a dynamic icestructure interaction model has been developed and...

Dynamic ice actions in the revision of ISO 19906

The second edition of the ISO19906 design standard contains changes in the informative appendix concerning dynamic ice actions. Challenges in application of the previous approach and advances in understanding of the dynamic ice-structure interaction process were the main motivation for the revision. The new guideline provides relevant...

Ice-induced vibrations of the Norströmsgrund lighthouse

The signature and occurrence of frequency lock-in (FLI) vibrations of full-scale offshore structures are not well understood. Although several structures have experienced FLI, limited amounts of time histories of the responses alongside measured met-ocean data are available in the literature. This paper presents an analysis of 61 measured...

Experimental validation of a model for prediction of dynamic ice-structure interaction

Vertically sided offshore structures subjected to level ice are designed to withstand the effects of ice-induced vibrations. Such structures are, for example, offshore wind turbines on monopile foundations, multi-legged oil- and gas platforms or lighthouses. For the prediction of dynamic interaction between ice and structures, several...

Ice-induced vibrations of vertically sided offshore structures

Offshore developments in ice-covered waters, such as the Arctic Ocean or Baltic Sea, have received increasing attention from the petroleum and wind power industries over the past decade. Sustainable developments in such waters can contribute to a balanced energy future provided that the deployed offshore structures are designed to be safe. The...

Ice-induced vibrations and ice buckling

Ice-induced vibrations can occur when flexible, vertically-sided offshore structures are subject to level ice such that the failure mode of ice is predominantly crushing. When the ice is relatively thin, or when the width of the structure is much larger than the ice thickness, the ice tends to buckle and subsequently fail as soon as the...