In recent years, the demand of improvement for existing port and harbor structures is increasing due to decreasing their tolerances by aging and improvement of seismic force design standards. Moreover, the renewal cost is tend to increase than original construction owing to clearance costs.
The present study proposes the economical seismic improvement by remodeling pile-supported wharf structures using existing piles. In this method, the old superstructure is cleared, and existing old pile is cut-off at the low water level. Then, a new pile is driven between horizontal centers of the existing old piles. Supporting strut is installed to connect the existing old pile and the new pile to transmit the inertial forces acting on the superstructure due to seismic motion. This method expects that the cost reduction by reducing number and diameter of the new piles and shortened construction period by omitting the pulling process.
We report the effectiveness of this improvement method through the model shaking test using 3D underwater shaking table comparing with standard pile-supported wharf model, validation of numerical modeling by dynamic finite element analyses using 2D FLIP and its real scale simulation for investigating effective specification of strut member.

Key Words: Attaching strut member, Added pile, Pile supported wharf, 3D underwater shaking table test, FLIP