Author(s): Sveinung Loset
Linked Author(s):
Keywords: No Keywords
Abstract: The Arctic offers tremendous potential to meet future global energy demand, but the exploration and exploitation need to be done in a safe and responsible fashion. Offshore, a part of this is the assessment of the ice actions and action effects on the structures being used in these icy waters. If we exclude the Arctic Basin, the water depths vary from shallow waters where fixed structures may be used to waters being a few hundred metres deep where floating structures have their advantage. The paper discusses the novel research at NTNU to estimate ice actions on floating structures from intact level ice, broken ice and ridges. The broken ice, either being broken by gravity waves in the marginal ice zone or being managed by icebreakers, has a special focus due to the fact that many offshore activities involve operation in broken ice where the processes causing actions from such ice are not well-known. This can be a drillship on Dynamic Positioning (DP) that is heavily relying on icebreakers breaking the ice upstream or ice interfering with a tanker in the wake of a terminal/offloading tower e. g. as in Varandey, offshore western Russia. The paper does also highlight numerical studies related to coupled behaviour of ice mass and steel structures during accidental collisions. Here the impacted structure undergoes irreversible deformation together with ice crushing. The concept of structural analysis in which the structure is allowed to deform inelastically due to rare and extreme actions is of crucial importance in engineering. Finally the paper discusses differences of actions on fixed and moored structures of the same type and geometry where ice induced vibrations may also play a role. Over the last three years in the above mentioned area of research, considerable work has been carried out at the Norwegian University of Science and Technology (NTNU) hosting a research-based innovation centre: Sustainable Arctic Marine and Coastal Technology (SAMCoT).
Year: 2014