The influence of variable-thickness ice on the loads exerted on sloping structures

A test program has been carried out to investigate the influence of non-uniform ice thickness on the loads exerted by an ice sheet failing against both an upward-breaking and a downward-breaking sloping structure. Tests were performed with both level and non-uniform ice sheets in a model test basin. The comparison of the loads was used as a basis to determine the 'effective' thickness (heff) of the ice sheet where heff=h\u3bc + kh\u3c3 where h\u3bc is the average ice thickness, h\u3c3 is the standard deviation of the ice thickness distribution, and k is a parameter that depends on structure slope and width and the mode of ice failure. For a wide, upward-breaking structure, k = 0.5 and 0.8 for slopes of 60\ub0 and 75\ub0, respectively. For a wide downward-breaking structure, k = 1.4 and 1.6 for slopes of -60\ub0 and -75\ub0, respectively. Based on these findings, analytical models for predicting ice forces on sloping structures have been modified to take into account the influence of non-uniform ice thickness.NRC publication: Ye