Menu

Experiments by Invited Researchers

 

Effects of the rubble accumulation on the ice action on structures

Project acronym: HyIV-HSVA-03
Name of Group Leader: Dr. Arnor Jensen
User-Project Title: Effects of the rubble accumulation on the ice action on structures
Facility: ARCTECLAB
Proceedings TA Project: RUBBLE ICE TRANSPORT ON ARCTIC OFFSHORE STRUCTURES (RITAS), SCALE MODEL INVESTIGATION OF LEVEL ICE ACTION
Data Management Report: Report

User-Project Objectives

The level ice load on offshore structures can be reduced by designing the structure geometry such that a bending failure of the level ice is promoted. The breaking of ice on large structure produces rubble ice travelling along the structure’s hull. The rubble ice has been acknowledged as one of the ice load components, and it is necessary to understand the physics of ice rubble transport and ice rubble. Therefore, a particular interest has to be brought to the study of the rubble ice transport and the physical and mechanical properties of the rubble. An experimental test campaign investigates the interaction between model structures and level ice. The experimental goals are given in the following list: · Replicate rubble ice creation and transport on structures · Investigate global and local ice action in relation to the accumulated rubble · Investigate morphological, physical and mechanical properties of the rubble in relation to ice and structure parameters · Develop effective measurement methods for the most sensitive parameters (rubble shape, ice density, rubble buoyancy)

Short description of the work carried out

Experimental results were obtained on: · Monitoring of level ice and rubble ice action on the structures. o The loads were measured on three load panels distributed in the vertical direction. o The ice breaking action could then be measured separately from the subsurface rubble action o The vertical distribution of the load was obtained. · Video monitoring of the subsurface level ice transport. Ice load and transport were studied in function of several parameters: o Structure width o Ice incidence, velocity, density, and thickness · 2D investigation of the level ice breaking and accumulation process, including: Measurement of the physical properties of the subsurface rubble o Tactile sensor monitoring of local ice load under bending failure o Measurement of buoyancy load from the subsurface rubble o Pile angle in dry and submerged rubble ice pile test · Level ice characterization: o Monitoring of salinity, temperature, flexural strength, density. Freeze-bond strength o A new density measuring method was successfully tested. · Rubble field characterization with depth profiling and measurement of the rubble resistance in punch tests.

Highlights of important research results

The experiment showed important results on the ice parameters effect on the ice load. A lower density / higher thickness provide additional rubble buoyancy / rubble volume under the ice sheet, thus changing the ice load. Effects from the velocity were also observed. The experiment presents important 2D underwater results on the ice bending failure and buoyancy measurements. The tactile sensor measurements permit to link the local ice load to the breaking process. A thorough analysis of the experiments will be conducted for paper publication in different conferences and as part of different Arctic Technology MSc and PhD studies.

Publications
Oda Skog AstrupExperimental Investigations of Ice Rubble: Shear Box and Pile Testing , 2012 Norwegian University of Technology (NTNU), Trondheim, Norway, Master Thesis
Henning Helg?yExperimental Investigations of Freeze-Bonds between Saline Ice-Blocks, Ice-Properties and Reproducibility , 2012 Norwegian University of Science and Technology (NTNU), Trondheim, Norway
Sergey Kulyakhtin et al.Rubble Ice Transport on Arctic Offshore Structures (RITAS), Part III: Analysis of Model Scale Rubble Ice Stability , 2013 Proceedings of the 22nd International Conference on Port and Ocean Engineering under Arctic Conditions (POAC?13), June 9-13. Espoo, Finland, Paper ID: POAC13-084
Wenjun LuRubble Ice Transport on Arctic Offshore Structures (RITAS), Part IV: Tactile sensor measurement of the level ice load on inclined plate , 2013 Proceedings of the 22nd International Conference on Port and Ocean Engineering under Arctic Conditions (POAC?13), June 9-13. Espoo, Finland, Paper ID: POAC13-087
Nicolas Serr? et al.Rubble Ice Transport on Arctic Offshore Structures (RITAS), Part II: 2D Scale Model Study of Level Ice Action , 2013 Proceedings of the 22nd International Conference on Port and Ocean Engineering under Arctic Conditions (POAC?13), June 9-13. Espoo, Finland, Paper ID: POAC13-136
Serre et al. Rubble Ice Transport on Arctic Offshore Structures (RITAS), Scale Model Investigation of Level Ice Action , 2014
Lu et al. Ice Load Measurement by Tactile Sensor in Model Scale Test in Relation to Rubble Ice Transport on Arctic Offshore Structures , 2014

Back