The study on ice load under ice-structure interactions has been started since 1993 as Japan Ocean Industries Association (JOIA) project. Medium Scale Field Indentation Tests (MSFIT) are conducted in 1996 winter as part of JOIA project and includes ice indentation tests, tests on physical properties of ice sheet and measurements of ice sheet deformation. This paper reports on the results of measurements of ice sheet deformation obtained from technique of stereo photogrammetry under ice- structure interactions in 1996 winter.
The failure range of the ice sheet includes the following three ranges;
a range of smaller strain rate (έ ≤ 10−4, ductile failure range),
a range of greater strain rate (k ≥ 10−2, brittle failure range) and
a rangeofmedium strain rate (k = 10−3, transition failure range).
The result of research efforts made so far has revealed that the maximum ice load occurs in the transition failure range. An effective evaluation technique to determine the strain range as one of the constituent elements of the strain rate, however, is not yet established. Evaluation of the strain rate is considered to have a serious impact on the evaluation of the ice sheet failure load. namely, evaluation of the structural design load. Accurate estimation and evaluation of the strain rate (strain range)is regarded as one of the major tasks. Considering that the strain range of the ice sheet can be estimated fi'omthe displacement range of the ice sheet, the authors ofthis paper measured ice sheet displacement caused by the indentation of a structure into the ice in the Medium Scale Field Indentation Test (JOIA (1995), Kawanmra et al (1996)) using the technique of photogrammetry, and estimated a way of determining the strain range.
