The pile system of the ship berthing structure at Derince Port was damaged by the August 17, 1999 Izmit earthquake. The reasons might the earthquake shaking and the effect tsunami waves in Izmit Bay, Turkey. Tsunami, is a special type of the wave and can be generated by the sea bottom deformation related to generally the earthquake or the earthquake triggered mass failure mechanisms. These kind of waves in shallow regions are assumed to resemble the solitary, cnoidal or N-waves. Theoretical approaches for the solution of run-up problems of tsunamis showed that the shape of the wave Is important (Tedepalli and Synolakis, 1994, Synolakis, 2001). The similar comparison may be made for the forces on the structure. The computation of the forces and displacements on the piled structures according to the attack of long waves can help to discuss the damage occurred at the piled system at Derince Port In this study by using the observed tsunami wave characteristics in Izmit bay, different type of long wave theories are applied to compute the forces and displacements on the damaged piled system at Derince Port. The reasons of the damage of the piled system are discussed by comparing the computed forces and displacements.