Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

Experimental investigation on ice loading mechanism of typical offshore structures
under the action of level ice
Yukui Tian, Chaoge Yu, Xuhao Gang, Shuai Kong, Shaopeng Ji, Yinghui Wang
China Ship Scientific Research Center, Wuxi, Jiangsu, P. R. China

ABSTRACTharmful to the structure. The changeable failure modes of level ice andthe complicated mechanical properties of sea ice make it difficult to
study the ice loading on offshore structures.
Experimental test is the most intuitive and reliable method to obtainand understand the ice loading on structure. In the past, scholars havecarried out a lot of research work on the experimental measurement
methods of structural ice load, involving structures such as lighthouses,
bridge piers, and platforms. For example, Jefferie monitored the ice
loads of Molikpaq in the Arctic, and obtained the platform's movement,base pressure and dynamic response at the same time (Jefferie, Hardyand Rogers, 1989). In 2003, Yue developed a proven test system tomeasure ice load and ice-induced vibration data on the MUQ andMNW platforms in the Bohai Sea (Yue, Bi, Yu and Shi, 2003). In 2014,
Lu used tactile sensors to analyze the distribution of the local ice loadof the structure during the interaction of level ice and wide-slope
structure (Lu, Serre, Høyland and Evers, 2014). Höderath calculated thepressure-area relationship in model test used tactile sensors (Höderathand Zimer, 2016). Nowadays, with the development of computer
technology, the use of numerical simulation to calculate the ice load ofoffshore structures has shown great potential, but the interaction
between level ice and offshore structure is a complex process, therefore
relevant research needs to be carried out. At present, the international
numerical methods for simulating the interaction between ice andstructures are mainly divided into Finite Element Method, Discrete
Element Method and PeriDynamics (Xue, Liu, Li and Han, 2020).
Konuk first use the Cohesive Zone Model (CZM) to simulate theinteraction between level ice and structure (Konuk, Gürtner and Yu,2009). Subsequently, Gürtner used CZM to simulate the interaction
between the lighthouse and sea ice, and compared the simulation resultswith the field test data. The simulated ice load is close to the test data
(Gürtner, Bjerkås, Forsberg and Hilding, 2010). The CZM shows its
applicability to the simulation of ice-structure interaction. This method
can more accurately simulate the process of ice from continuous action
to breaking and the accumulation of broken ice.

Level ice is one of the main ice types encountered by the offshore
structures operated in ice zone, while vertical and inclined structures
are the commonest configurations, so it is of great significance forreinforced ice-resistant design and safety evaluation to study the ice
loading on the typical structures under the action of level ice. Firstly, inthis paper, the processes reflecting the interactions of level ice versus
the typical structures were analyzed generally. Then, a series model
testing on the ice loading mechanism of the typical structures wasperformed, the failure behavior of the level ice and the characteristicsof the ice loading on the structures were investigated. Finally, the test
data were applied to verify a self-developed numerical simulation
model based on the cohesive element model and the degraded
constitutive model of sea ice, the simulation effects of the crack
propagation and crushing process of level ice were assessed, and theresults of ice loading from the numerical modeling with those from thephysical model testing were compared. The work of this paper can lay
an important foundation for the numerical and experimental researchesof ice loading and provide technical reference for the design andconstruction of the offshore structures in ice zone.

KEY WORDS: level ice; typical offshore structures; ice loadingmechanism; model testing; numerical modeling
INTRODUCTION
The offshore structures for the exploitation of polar resources,
including drilling platforms, production platforms, and storage andtransportation ships, are often faced with the danger of sea ice
collisions during operations. Historically, the platform structure in
Cook Bay, the lighthouse in Finland, and the jacket platform in theBohai Sea of China had all been collided and squeezed by ice floes orlevel ice and collapsed (Long, 2019). The ice load of structure is an
important input for the enhanced design of offshore structures, so thestudy of Ice loading on structure is particularly important. The
mechanical properties of sea ice are complex and the macroscopic
shape is changeable. Icebergs, level ice and floe ice are all common
types of sea ice in the polar regions. Because offshore structures areoften far away from the sea where icebergs exist, floe ice and level ice
are the types of sea ice that offshore structures often encounter. The
process of level ice-structure interaction is more complicated and willcause ice-induced vibration under certain conditions. It is extremely

Generally, there are two types of offshore structures commonly used inice regions. One is a vertical structure including vertical cylinder andvertical polyhedron structure, and the other is an inclined structure
including sloping plate and cone. So, during the test based on the Small
Ice model Basin (SIMB) in China Ship Scientific Research Center(CSSRC), the vertical cylindrical structure, vertical cube structure andinclined plate structure were selected as the model structure. Then thefailure behavior of the level ice and the characteristics of the ice

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