The paper is focused on the study of challenges in determining ice loads on the structure interacting with drifting ice in a scenario not covered by effective national and international regulatory documents, particularly, ISO 19906. The platform consisting of two supporting modules, each having inclined and vertical faces in ice interaction area is studied in the paper. This structure is a possible alternative of the supporting part of the ice-resistant platform for the development of the oil/gas field located in an ultimately shallow water area of the Northern Caspian Sea.
Current standards outline a restricted class of ice-resistant gravity and pile-gravity type structures for which theoretical methods of determining global ice loads have been developed. Those are structures with vertical (flat or cylindrical) or inclined (flat or conical) faces, and multi-leg structures. Rigorous ice conditions typical for certain areas, and some specific procedures of transporting structures to and installing on site, result in solutions non-standard in terms of the shape and type of structures being designed. Thus, a possible alternative of the supporting part of the ice-resistant platform for the development of the oil/gas field located in an ultimately shallow Northern Caspian water area is a structure consisting of two supporting modules, each having inclined and vertical faces in ice interaction area. Model tests have been performed in the ice basin of Krylov Shipbuilding Research Institute to determine loads on those structures from drifting ice features. A complicated ice cover failure regime arisen from a combination of various failure modes such as bending along inclined faces, crushing against vertical faces, the formation of main cracks and fractures due to interaction between the supporting modules, was observed in testing. Design ice loads on the same structures were calculated based on provisions of effective regulatory documents. The model test results were then compared with the loads calculated as per the above provisions.