Full-scale flexural strength of sea ice and freshwater ice in Spitsbergen Fjords and North-West Barents Sea

The present paper describes the results of a rather long series of full-scale, flexural-strength tests on ice beams (over 70 tests) performed in-situ in seawater and freshwater ice at and near Svalbard archipelago during the period 2010-2018. Ice thickness varied in the range of 0.2-0.8 m. Based on a comprehensive analysis of the test data, characteristic plots of ice flexural strength and effective elastic modulus versus the liquid-brine-volume fraction, which varied over a large range of 0-0.2 and were obtained specifically for the geographic region under consideration. The observed range in flexural strength for seawater ice was 0.109-0.415 MPa, and the same for freshwater ice was 0.275-0.807 MPa. The test results with cantilever beams did not show a dependence of the ice flexural strength on the direction of bending force applied to the free end of a beam. Experiments complemented with numerical analysis have demonstrated that stress concentrations in root sections of cantilever ice beams have significant impact on the accuracy of measurement of flexural strength of freshwater ice. It is noted that modifications have to be introduced in the methodology that is used to measure the effective elastic modulus of ice based on the free-end deflection of cantilever ice beams.