Physical model tests are conducted for the investigation of ice forces acting on the structure with combined cone by using the new kind of non-frozen synthetic material. The total ice forces are measured and the flexural failure processes of model ice sheets are recorded. The measured ice forces are compared to the predicted results of Croasdale's and Ralston's theoretical model and the effect of various parameters, such as ice velocities, inclined angle, ice thickness and waterline diameter are discussed.
The oiling platforms and the offshore structures in the northern area of the Bohai Sea in China often encounter the impact of sea-ice in the winter, which seriously disturbs the normal operation and even threatens the safety of workers on the platform. Recent years, structures with combined cones have been used to resist ice-induced vibration in the Bohai sea(Yang, Guojin, 1991) and excellent results have been achieved. However, even though there have been a lot of studies on the mechanism of the interaction between conical structures and ice sheets, the ice-breaking mechanism on structure with combined cone has not yet been understood. And the investigation on the effect factors, such as the shape of the structure, the physical properties of ice, the rate of ice movement, the non-simultaneous failure and many other parameters, are still required. Various prediction formulas have been proposed for ice forces acting on an upward-breaking cone. Croasdale(1980) developed an analytical model based on an elastic beam on an elastic foundation. This model was later modified to account for three dimensional effects by Croasdale and Cammaert(1994). Ralston(1977) developed a full three dimensional model based on plasticity theory. Edwards and Croasdale(1976), Kato(1997) and Hirayama and Obara(1986) established empirical formulas based on laboratory experiments.
