Estimation of Local Ice Pressure Using Up-Crossing Rate Available to Purchase

Ice load estimation is required for offshore structures designed for arctic and sub-arctic conditions. This paper focuses on the estimation of local ice pressures. The ‘event-maximum’ method for local ice pressure analysis is based on the maximum pressure of a given event; other local peaks in the data are not included. To study how this may affect local ice pressure estimates, a method based on the up-crossing rate was developed. Field data from 1982 Polar Sea arctic trials in the Beaufort Sea are processed as a time series. Up-crossing rates at different local pressure levels are obtained for local areas of interest. A relationship between up-crossing rate and local pressure-area results is established. Results from the analysis of full-scale data using the event-maximum method are presented in a companion paper. For a sample case, local ice pressure estimates obtained using the up-crossing rate method are compared with those presented in the companion paper, based on analysis using the event-maximum method. The local pressure-area relationship is found to be similar for both the up-crossing rate method and the event-maximum method. Both methods and corresponding analysis results are compared.