A five year ice load research program is being executed to enhance design ice load prediction accuracy for vertical sided structures by the Japan Ocean Industries Association (Saeki et al., 1996). The program is comprised of extensive indentation tests and computer code development capable of simulating dynamic ice/structure response, local, global and foundation loads. As a first year test program, four vertical rectangular indentors and one cylindrical indentor were tested in small scale with setting model stiffness relatively high to attain stable nonsimultaneous failure modes. Tests were conducted with varying ice thickness, indentation velocity and crushing strength. Segmented ice pressure panels were equipped to measure local and global ice pressure characteristics. This paper summarizes the experimental results with respect to the tendency of the global and local load. From the segmented panel data, local load characteristics regarding pressure area relation and a width of the independent zone are discussed.
Ice load estimation on vertical sided structures is a classical problem, although the designer encounters many difficulties when selecting rational design loads. Ice interaction against a vertical sided indentor exhibits very. complex local failure and that makes it difficult to develop mathematical models or to predict ice load using scaled ice tank tests. Croasdale(1988) reviewed the practical ice load estimation methods on vertical structures. He introduced three conventional methods, namely, Korzhavin's equation (1962), reference stress methods (Ponter et al., 1983) and cut-off stress methods (Walden et al., 1987). Sanderson (1988) claimed that a Korzhavin like equation predicts ice loads much higher applying a contact factor of 0.3 that is deduced from laboratory indentation tests. The contact factor required to match the full scale data would be less that 0.1 and typically the order of 0.07.
