Level ice interaction with sloping and conical offshore structures

The use of sloping sided or conical structures is often a favorable design option for structures placed in ice covered waters. An understanding of the mechanics involved during level ice interaction with conical or sloping sided structures is necessary for safe structural design in environments where ice cover is present. This work provides a review of the failure mechanics involved during an ice interaction with a conical or sloping sided structure and the methods which have been developed to model these types of interactions.;The results presented in Chapter 3 show that the methodology used to predict the flexural strength of ice based on brine volume alone may well lead to an over estimation of the flexural strength of ice for full scale interactions. This is achieved by using full scale data from the icebreaker Oden during the International Arctic Ocean Expedition in 1991 where the icebreaker Oden was part of a three vessel expedition to the central Arctic Basin. The results of the work show a significant reduction in flexural strength when compared to the methodology which considers brine volume only.;In Chapter 4 a probabilistic model was developed to determine extreme level ice loads acting on the conical Confederation Bridge piers in the Northumberland Strait. A Monte Carlo technique was utilized to simulate the ice environment and to derive the annual maximum ice loads on the structure. In order to achieve this, full scale data was obtained from public sources and fitted with probability distributions to model the input parameters.;In Chapter 5 the author has used data published by the Confederation Bridge Ice Monitoring Program and the National Research Council to validate the probabilistic model developed in Chapter 4. The model developed is believed to provide an appropriate representation of the level ice loads acting on the Confederation Bridge piers. The model which was developed in this work produced results which suggest that the 10 year ice load is 8.6MN, whilst the maximum load published by the Confederation Bridge Ice Monitoring Program is 8.4MN for the first 10 years of operation. (Abstract shortened by UMI.);The sensitivity of the ice loads, estimated by the Croasdale Model, to the variation in input parameters has been studied in this work. From this analysis, it was determined that if a rubble pile was present on the structure, the flexural strength of ice was not a significant factor affecting the ice load. There were however a number of scenarios which were outlined for which the flexural strength of ice was of significance. A ship ramming event is one such scenario for which the flexural strength of ice plays a significant role in limiting the maximum ice load.