Use of Ice as a Load-Supporting Surface

摘要

Ice in the mass is perhaps best described as a highly viscous material having the characteristics of a solid. It may fracture like a brittle material, or it may flow and deform gradually depending upon the intensity of the stress and rate of loading, the temperature, the degree of confinement and the structure of the ice itself. The proportional limit of the stress-strain curve for ice has been reported to be on the order of 20 to 25 psi or even less. At higher static load intensities ice will deform at a steady rate; the higher the stress, the higher the rate. Since floating ice is normally stressed to far beyond the proportional limit in order to carry useful loads, theoretical stress analysis methods using the theory of elasticity become no longer strictly applicable and must be applied with caution. Fortunately most load applications of appreciable magnitude on floating ice involve periods of stress duration much shorter than the structural designer deals with in the case of permanent structures, such as buildings and bridges, and the plastic deformation is usually not as serious a matter as it might seem.