Ice Pressure Against Dams: A Symposium: Studies of the Effects of Temperature Variations

The problem relating to the magnitude of the horizontal ice pressure produced by a solid sheet of ice as a result of rapidly rising temperatures has not found a satisfactory solution. Investigations have yielded unreliable and somewhat contradictory results. This paper describes an investigation that was undertaken by the Swedish State Power Board. In the experiments, made with an arrangement installed in a freezing chamber, a pressure of 20 tons per m (13,400 lb per lin ft) was obtained with ice 60 cm (23.62 in.) thick. This result is somewhat unreliable, however, owing to the presence of certain additional effects during the experiment. From calculations made on the buckling of an ice sheet, a probable maximum ice pressure of from 30 tons per m to 40 tons perm (20,000 lb per lin ft to 27,000 lb per lin ft) is found. It would seem that an ice pressure of similar magnitude may also be set up under certain unfavorable local conditions in consequence of variations in the water level, with an ice sheet having a limited expanse of from 20 m to 40 m (65 ft to 130 ft). As a rule the ice pressure resulting from variations in the water level will be less, but it may occur in many places with appreciably greater frequency than ice pressure resulting from extreme temperature variations.