Experimental study of the ice loads on multi-piled oil piers in Bohai Sea

For a newly built multi-piled oil pier in Bohai Sea, a series of model tests were performed to evaluate the ice loads acting on the structure and the corresponding pile-group effect. Totally, 6 different ice conditions were considered in model tests, and the ice forces on each pile were measured. A variety of failure modes of ice are observed under different conditions, which result in ice force changing. The measured ice forces on each pile were compared with the computations by the ISO standard. Pile-group effects were thoroughly discussed, including interference effect, sheltering effect, non-simultaneous failing effect and combining influence. Integrated reduction coefficient and non-simultaneous failing coefficient were introduced to describe the influence of these effects. It is shown that between interference effect and sheltering effect the dominant effect for the integrated reduction varies with different piles. Besides integrated reduction, non-simultaneous failing is also investigated for pile-group, and the variation trends of these two effects are opposite as the increasing ice attack angle. Furthermore, the corresponding influence factors on total ice loads were discussed as well.