Abstract
A procedure is developed for predicting the maximum impulsive force on structures with an arbitrary opening ratio due to the collision of timbers drifted by borerlike tsunamis. In the course of the development, variation features of the apparent inertia coefficient, the moving velocity and the impact duration time of timbers with the opening ratio, the relative bore height and the timber's slenderness ratio are experimentally examined, and it is found that the distribution form of the apparent inertia coefficient with the opening ratio is parabolic, the distribution form of the impact duration time with the opening ratio has a similarity, the moving velocity and the impact duration time are almost under the rule of Froude law and so on.
