Wave Force Acting on the Pelprene Protective Device

Abstract

Recently large bridges have been constructed in navigable waters congested by ships, so that ship collision with bridge piers is on the increase. To decrease the accidents various kinds of protective system are planned. The pelprene protective devices is developed for one of these protection systems. The shape of the cross section is honeycomb which is made from thermoplastic polyester elastomers named Pelprene. Usually honeycomb structure have been used for the bumper of the cars and have seldom been used for the offshore structure. In this paper the authors made a study of the wave forces acting on the protective devices by model experiments to decide how to install them around the bridge pier. The following results are obtained. The wave forces acting on the pelprene protective device model are smaller than that of the identically shaped box model. The horizontal forces : Fx have a maximum value at the region ; λ/L=3〜5. The vertical forces : Fz are smaller than horizontal forces in all the region of λ/L and have a flat distribution. In comparison with a model made from steel, Fx of the pelprene model is larger than that of steel model and Fz is smaller than that of steel model.