First, this study, a simplified collision model of pile protective structures against a navigation vessel was proposed and verified. The model of pile protective structure were composed by two plastic hinges at bottom of capping slab and the inside of ground. A nonlinear equation of motions were proposed in consideration of the kinematic energy, potential energy and deformation energy in collision event. The simulation capacity of the proposed simplified model of collision were verified by the precise finite element collision analysis of the vessel and the pile protective structure.
Second, the deformation-energy curves of the plastic hinges of piles and the vessel bow, which are the major energy dissipation mechanisms of a pile protective structures, were estimated, and the parametric study was performed using those curves to apply the simplified model of collision which proposed. Considered parameters were the mass of slab, the number of piles, the mass of vessel and the collision velocity of the vessel, and collision behaviors were analyzed in ranges of parameters. As results, the difference of energy dissipation mechanism of two pile types(filled and non-filled) were revealed.

The collision behaviors of the pile protective structures could be tuned by the control of the inertia mass of capping slab.
It is judged that it can be applied to determine the efficient energy dissipation ratio of the ship designed for designing a pile protective structures and the protective structure. And it is judged that it will be possible to design and review simple and various scenarios using the simplified model of collision.

Therefore the simplified model of collision can be used in a primary design and optimal design. In addition, it can be applied to the development of a simplified model of collision for collision protective structure of other types.