Theoretical development of forces on cylindrical ice booms

This paper presents generic equations and analyses of a cylindrical pontoon boom's capacity to retain ice. The presentation arises out of actual booms deployed on the St. Lawrence River downstream of Montreal but are valid fo r any cylindrical ice boom deployment. The boom's retention capacity not on ly relates to the pontoon's dimensions but also directly relates to the ice sheet's characteristics including thickness and strength. The role of fric tion and the geometry of the ice at the interface of the pontoon also deter mine the behavior of the structure and the associated line loads that devel op. The analyses of environmental load show that the traditional theory of ice, acting as an aggregate, cannot explain observed values. Instead, this paper suggests that the ice upstream of a boom is a relatively coherent she et. The internal strength of the ice sheet is compared to the environmental forces and the boom's capacity. These analyses improve understanding of th e observations of the St. Lawrence booms made over the last 30 years.