To ease fabrication and reduce cost, industry has considered replacing the smoothly curved surface with a multifaceted one for conical structures. Most analytical methods and calculation procedures, including those recommended by API (RP 2N), were developed for smoothly curved conical structures. To account for the particular features of the faceted cone, an analytical model is presented in this paper to estimate the ice ridge crack loads on a multifaceted conical structure. The theory of an elastic beam on an elastic foundation was employed to determine the maximum bending moment in the ice ridge. The effects of facet width, ridge length and the attached ice sheet were taken into account. Three contacting conditions between the ridge and the structure were considered by simulating them as three different loading conditions. It is also shown that the elasticity model for the case of smooth cones is a particular case of the present model.
Conical shaped surface was proposed for use with fixed platforms for development of oil and gas in Arctic regions. Because this configuration can induce bending failure of ice, which will result in smaller ice loads on the structure, a lot of effort has been made to calculate the ice loads on this type of structures. To more efficiently use this concept, industry has proposed to use a multifaceted surface to replace the smoothly curved surface, which can further reduce the cost and can ease the fabrication as well. This, however, has prompted a need to have appropriate load formulas or some means of calculating ice loads on this type of configuration. Concern has been raised especially in regarding to calculation of multi-year ice ridge loads because the ice ridges can exert loads much larger than the ice sheet loads on a structure.
