Ice forces on a multifaceted conical structure

• Main Author: Wang, Zhiguo
• Format: Thesis
• Language: English
• Published: Memorial University of Newfoundland 1997
• Subjects: Arctic; Canada
• Online Access: https://research.library.mun.ca/1276/; https://research.library.mun.ca/1276/1/Wang_Zhiguo.pdf; https://research.library.mun.ca/1276/3/Wang_Zhiguo.pdf

To simplify fabrication and reduce costs of conical structures for arctic offshore development, a multifaceted conical shape was proposed to replace the conventional smooth cone. This raised a number of concerns about the mechanisms for ice interaction with this multifaceted conical structure (MCS) and the validity of analytical models which were developed for the smooth conical structure (SCS). A vertical neck at the top of the MCS was proposed for a prototype and industry has desired a large size for this neck, i.e., its diameter to be only slightly smaller than water-line diameter. This raised another concern: what was the effect of this vertical neck on ice loads ? -- To address these concerns, a university-industry joint program (NSERC file # 661- 119/88) was initiated to carry out a series of test program. The program involved three series of tests carried out in three Canadian test facilities (ESSO Resources Canada, Calgary; NRCC's Institute for Mechanical Engineering, Ottawa; and NRCC's Institute for Marine Dynamics, St. John's) with structural models at scales of 1:50 to 1:10 and at a cost about 1.3 million Canadian dollars. The results of these tests were presented in test reports published by each facility; while presenting these test results no detailed analysis was carried out to understand the ice/structure interaction in a comprehensive manner. The data contained in these test reports have been used in this study to understand in depth the various interaction scenarios possible between a multi- year ice ridge and the MCS. -- The direct analysis of the test data, presented in this study, covers answers to most of the concerns raised by the offshore industry but is not limited to them. Besides the ice failure mechanisms involved in the process of ice interaction with the MCS models, the parameters analyzed include neck size, structural orientation, ridge width, and the events that caused the maximum ridge loads. In the analysis of the ice failure mechanisms, three ridge failure patterns are ...