Ice boom loads in the St. Lawrence River, 1994-95 & 1995-96

In recent years, a new type of ice control boom has been developed by the Canadian Coast Guard to improve the formation of a stable ice cover along the St, Lawrence River, The new boom uses cylindrical steel pontoons in place of the rectangular timbers that have traditionally been used, This paper presents an analysis of the loads measured in ice control booms deployed at three locations during the winters of 1994-95 and 1995-96. Loads up to 1250 kN were recorded, The loads are highly variable over time such that the maximum load is always much larger than the average, The nature of the loading varies throughout the winter, reflecting the type of ice regime that prevails along the river, Daily maximum loads can be well described by the Gumbel probability distribution, A technique is presented for predicting expected loads over longer time periods.