Shoulder Ice Barrier Ice Tank Testing—Part II: Estimation of Breaking Length and Block Size Using Image Analysis Available to Purchase

When studying ice interaction on sloped structures, a key parameter that is usually reported after experiments and observations either in Full Scale or Model Scale is the breaking length associated with the ice failure. Moreover, either for numerical modeling or load calculations the size of the blocks generated during ice-structure interaction that accumulates rubble is of importance. In this paper, the technique of image analysis has been used to obtain values of the breaking length and the ice block sizes generated during model tests of a Shoulder Ice Barrier (SIB)-ice interaction. 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 its general performance. A brief description of the model tests and the image analysis technique used to analyze the data is done. A total of five experiments where ice thickness, ice flexural strength and shoulder inclination were varied, are analyzed. Results of the breaking length analysis show that there is a characteristic change in the breaking length associated with the transition from ice interactions on the bare structure (Phase 1) and interaction onto accumulated rubble (Phase 2). Average values of the breaking length of both phases for each experiment are presented. Since the information regarding breaking length in structures that accumulate rubble is sparse, the experimental results of Phase 1, where the rubble accumulation is still small, are compared with the predictions from three different models presented in the literature for sloped structures, under similar ice conditions, that do not accumulate rubble. The comparison allows concluding that the breaking phenomenon is being reasonably well modeled in the experiments. The block sizes of the upper layer of the accumulated rubble were analyzed and the block length and width distributions were found for each experiment. A linear trend was found between block size and ice thickness. A linear fitting of the data was performed in order to obtain simple equations which give an upper limit of the length and width of the ice blocks generated during the SIB-ice interaction as function of the ice thickness. The results may apply for ice interaction on sloped structures in general as well.