Ice Forces on Port Structures Resulting from Moving Ships

Results are described of experiments carried out in Thunder Bay Harbour in March, 1984, to measure ice forces on a port structure. Ice forces were measured by installing five pressure panels at critical locations defined by using a finite element model. An instrumentation package was set up to continuously monitor the measured forces and initiate an alarm, should the forces exceed 20% of the maximum allowable forces. A Canadian Coast Guard icebreaker was used for the tests in two modes of operations, with and without an Air Cushion Icebreaking Bow (ACIB) notched to its conventional bow. The first mode of operation resulted in exceeding the maximum allowable pressure and the test was aborted. The second and third tests were done after notching the icebreaker to the ACIB resulting in lower ice pressure on the structure. These results are also compared to the thermal pressure resulting from the air temperature fluctuation and the associated ice expansion.