Development Of A Three-Dimensional Model For Ice Rubble Interactions On Conical Structures

• Main Author: Wong, Chee
• Other Authors: Brown, Thomas
• Format: Master Thesis
• Language: English
• Published: Graduate Studies 2014
• Subjects: Engineering > Civil; Ice Load; Ice Rubble; Conical Structures; Ice-Structure Interaction; Ice Engineering; Confederation Bridge; Ice Sheet; Prince Edward Island
• Online Access: http://hdl.handle.net/11023/1270; https://doi.org/10.11575/PRISM/25677

Offshore structures in waters where ice cover is prevalent from four to nine months a year have been constructed for the last 30 years to extract natural resources and to transport people and goods. Many of these structures are conical or sloped faced in shape, where flexural failure becomes the dominant mode of failure for the ice sheet. This reduces the magnitude of ice structure interaction loads in comparison to other modes of failure. In this particular study, ice interactions with the piers of the Confederation Bridge were examined. Since the 13 km bridge, spanning across the Northumberland Strait between the eastern Canadian provinces of Prince Edward Island and New Brunswick, opened in 1997, the Confederation Bridge Monitoring Program has been instituted to monitor ice interactions with the piers through the installation of video cameras, load sensors, and deformation sensors. Through 15 years of the Monitoring Program, archived video footage have shown that the highest interaction loads recorded on the piers are a result of ice rubble piles sitting on a level ice sheet and on the pier surface as the level ice sheet continues to fail in flexure. Various researchers have devised flexural failure models for ice and conical structure interactions. Each model shares the same principle of the ice sheet being modelled as a beam on an elastic foundation and each has different limitations in precisely predicting interaction loads. Some models do not incorporate the rubble pile, while other models make over simplified assumptions for three-dimensional behaviour. The proposed three-dimensional finite element model aims to reduce some of these limitations through: modelling the bilinear-shape ice rubble piles with a more rigorous slope stability method, modelling the geometry of the rubble around the cone through small-scale tests, adding a driving force in keeping the rubble pile intact during the interaction, and accounting for eccentric offsetting moments during ice-structure contact. Ten full-scale interaction ...