A study on ice loads during ice/structure interactions was started in 1993 by the Japan Ocean Industries Association (JOIA). The purpose of the tests was to investigate ice loads and ice failure characteristics, and to establish a new method of estimating ice loads during ice/structure interactions. The tests consisted of ice indentation tests, tests on physical properties of ice sheets, and measurements of ice sheet deformation. This paper describes for three indentation velocities, the relation between ice sheet strain area and ice failure modes due to ice/structure interaction during a winter test in1998.
Appropriate evaluation of ice load is essential in the design of structures such as revetments and piers to be constructed along seacoasts, lakes and marshes in cold areas. It is known that the ice load is influenced by ice thickness, indentation velocity, V, and the structure width, W. It is especially affected by the strain rate (d e / d t) defined by indentation velocity and ice sheet strain area. The strain area was defined as the area of the ice sheet experienced strain during indentation. In calculations of the strain rate made so far, the ice sheet strain area has generally been defined only in terms of structure width, 2W or 4W. There are some theories that have provided a rational evaluation of the dependence of the ice load on ice thickness and indentation velocity. Accordingly, when evaluating the design load of structures, it is very important to define the area of strain under load conditions and to keep track of the relationship between strain velocity and maximum ice load. In the present study, the authors embedded strain gauges into the ice sheet to measure the strain relative to a concrete structure and a steel structure in a field test.
