A method of computing the pressure of ice sheets drifting on structures of the multilegged type for a fixed probability is presented. This method is based on the idea of the variability in time of ice loading on the column of the structure. Variability of the ice loading is explained by the variability of the ice sheet parameters, including geometric and kinematic characteristics. These characteristics are random values, the process of ice-structure interaction is therefore a ramdom one. The probability for the highest values of ice pressure occuring on all columns simultaneously is practically equal to zero. The cases of simultaneous ice loading on columns in some range of their highest values are considered.
Applying rational methods to ice forces calculation promotes increasing reliability The parameter A - geometry, hardness and structure elements location and other structure characteristics are set up during the design. The rest of the data are to be accepted on the basis of observations. Design ice forces on the supports depend on the choice of these values and the right choice of equations for calculation. It is known that the load from drifting ice fields or of ice sheets pushing on a rigid structure of the "Monopod" type is defined by formulas in which the values of h and R are accepted, as a rule, as the maximum values with a sufficient probability of occurence for the period considered [4, 9]. In case of interaction between a group of pile and on ice field there are some differences. First of all, simultaneous occurence of maximum load on all piles is not a real possibility. The results of experimental investigations of interaction between ice fields and multilegged type structures are presented in [8, 15, 18].