To protect the vertical oil pipes from ice loads in ice infested shallow water or tideland, a new-concept structure is designed. The idea is different from traditional ice-resistant, it makes ice sheet broken in front of the vertical oil pipes, and then the broken ice pieces are permitted to climb the structure and move to the behind structure. Then the broken ice pieces, not ice sheet, will act on the vertical oil pipes. In this way, the ice loads on the vertical structure are induced and some of ice loads are absorbed in the process of ice broken in front of the new concept structure. The new structure can be made of reinforced concrete. It is cheaper and easily manufactured. Because the broken ice pieces loads on the vertical oil pipes are decreased, the protection of the oil operation structures becomes simple and cheaper. In this paper, the idea of the structure is given and preliminary model tests are introduced, and the scope of future work is discussed briefly.
Because Bohai Sea is struck by cold wave in winter, sea ice takes place on the sea in various degrees. Under the control of severe cold weather, severity sea ice could occur on the Bohai Sea with icing over 70 % of the sea surface. Usually, the ice period is about 82-132 days. The range of drift ice is much larger than that of fast ice. The ice amount, type, pile-up, fast ice distribution and drift ice distribution in Bohai not only have remarkable variation year after year, but also vary monthly and daily. The detailed ice characteristics are concluded as (Yang G, et al, 1991): 1. Usually, the maximum level ice thickness is 20 cm in Laizhou Bay, 25cm in Bohai Bay and 45cm in Liaodong Gulf.