Interaction between Ridges and Truncated Conical Offshore Structures

Most of Canada's ice regime is first year ice that includes extensive rubble fields and densely ridged areas. This study proved the need of a model that calculates the load resulting from the interaction between first-year ridges and truncated conical offshore structures. An extensive monitoring program has been held for the last twelve years concentrating on the interaction between the truncated conical piers of the Confederation Bridge and different ice features. The program provided a complete set of data because for every event, the load of interaction has been recorded on one hand while the geometric properties, failure mechanisms, and the velocity of the ridge causing this load, has been recorded on the other hand.;The shear-cap model which is a material model developed by Heinonen (2004) has been used in an analytical model that calculates the load resulting from interaction between keel ice rubble and truncated conical offshore structures. The video analysis led to some observations concerning the consolidated layer failure mechanisms when interacting with the Confederation Bridge piers (truncated conical piers). As a result, a modified consolidated layer flexural load model based on Croasdale et al. (1994) model has been developed. The sum of the keel load calculated by the newly developed analytical model and the consolidated layer load calculated by the modified flexural load model represents a new analytical model that calculates the load resulting from the interaction between first-year ridges and truncated conical offshore structures. In order to verify the accuracy of this analytical model and that the results obtained using the newly developed load model are a significant improvement over the results obtained from previously developed models, comparison between the loads recorded at Pier P31 of the Confederation Bridge and the loads calculated by the new model has been held. Also, a finite element model that simulates the interaction between ridges and the pier (P31) of the Confederation Bridge has been developed. Both comparisons made it clear that the new analytical model introduces a noticeably better results and more accurate values of the loads resulting from interaction between ridges and truncated conical offshore structures.