Shoulder Ice Barrier Ice Tank Testing—Part I: Qualitative Description of a Shoulder Ice Barrier-Ice Interaction During Model Tests

This paper describes qualitatively and through visual observations the ice-sheet interaction with a Shoulder Ice Barrier (SIB) during model tests. The model tests were performed in the Hamburg Ship Model Basin (HSVA) during July 2007. Since the SIB represents a new concept in ice barrier structures, model tests were intended to evaluate the general performance of the SIB. The paper describes seven different experiments where the ice thickness, the ice flexural strength, and the shoulder angle of the SIB are the parameters varied among them. The results are presented in two sections. The first part refers to observations common to all the experiments, where ice failure mode and shoulder performance are given specially attention. The second part describes more into detail the phenomena observed in each particular experiment. The former analysis allows the visual identification of three phases (as mentioned in previous publications), and gives a deeper insight of the characteristics of each phase. The later analysis, on the other hand, allows achieving interesting conclusions about the SIB performance under different ice conditions and with different shoulder inclinations. A comparison between the failure mode observed during the model tests and observations presented in the literature of full scale vertical and sloped structures-ice interaction with rubble accumulation is performed. The similarities found in the study between model and full scale observations lead to suppose that the observed model test behaviour may be expected during ice-SIB interaction in full scale. However, some events that could be associated with problems of the model ice scaling are highlighted. As a conclusion regarding SIB performance, it is shown that the shoulder section, which is the principal innovation of the concept, accomplishes its task satisfactorily and represents a key modification to traditional ice barriers in generating smaller ice pieces and avoiding ice overriding.