THE DYNAMIC BEHAVIOUR OF A FLOATING CABLE-MOORED PLATFORM CONTINUOUSLY IMPACTED BY ICE FLOES

This report is in microfiche form. The dynamic behaviour of a floating, moored platform undergoing continuous impact with a field of ice floe was investigated using a model platform in the ice towing tank of the Iowa Institute of Hydraulic Research. The study was directed to investigate the influences of ice-floe diameter and speed on the ice-related forces and motions experienced by a moored platform of conical hull form. Experiments showed that, for both the moored and the fixed conditions of platform support, the maximum and average values of mooring and restraining (ice-related) forces due to ice-floe impact increased with increasing diameter of ice-floe; the value asymptotically approached that associated with the impact of a floe of annual ice much larger than the platform. This increase is attributed primarily to the added resistance required to flexurally break an ice floe impacting against the platform. The average and maximum values of mooring forces experienced by the moored platform increased with increasing speed of ice-floe impact. The average and maximum values of vertical restraining forces experienced by the platform in the fixed condition decreased with increasing speed of ice-floe impact, The maximum mooring forces experienced by the test platform and the design value of mooring force for the platform "Kuiluk" were found to be in very good agreement.