An evolving design philosophy for port structures in many seismically active regions reflects the observations that: -The deformations in ground and foundation soils and the corresponding structural deformation and stress states are key design parameters. -Conventional limit equilibrium-based methods are not well suited to evaluating these parameters. -Some residual deformation may be acceptable. Performance-based design is an emerging methodology whose goal is to overcome the limitations present in conventional seismic design. Conventional building code seismic design is based on providing capacity to resist a design seismic force, but it does not provide information on the performance of structure when the limit of the force-balance is exceeded. If we demand that limit equilibrium not be exceeded for the relatively high intensity ground motions associated with a rare seismic event, the construction cost will most likely be too high. If forcebalance design is based on amore frequent seismic event, then it is difficult to estimate the seismic performance of the structure when subjected to ground motions that are greater than those used in design. In this thesis a case study will be carried out on a typical port structure to show the performance evolution aspects and its comparison with damage criteria and performance grade in performance-based methodology.