Author(s): R. Frederking; B. Sand; D. Sudom
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Keywords: No Keywords
Abstract: The ability to reliably predict ice forces generated by ridged ice features is very important for the design of offshore structures in many cold regions. Analytical models have been developed for predicting the loads on a structure due to interaction of an ice ridge keel or rubble, but few data exist for validating these models. In the present paper, the ice keel load distribution across the face of a vertical cylindrical structure is assessed. Ice load data collected in 2002 as part of the STRICE project at Norstr"omsgrund lighthouse were examined. Events for which the instrumented part of the lighthouse was responding only to ice keel loading were analysed to quantify horizontal ice keel pressures. The results have been compared with predictions of a numerical model. Numerical modeling is also used to predict the global ice forces and ice failure behavior for ridges of different size. From both full scale field data and numerical simulations of ridge interaction with the lighthouse, a trend of higher forces with increasing keel depths can be seen. In addition to generating larger global loads, larger ridges appear to create greater local loads around the waterline of the cylindrical structure. The load distribution across the lighthouse is not uniform. For some events, the forces on the load panels show a parabolic-type distribution while for others a different load distribution with two maxima is seen.
Year: 2014