Offshore bridges play an important role under multi-hazard circumstances. In 1989, the San Francisco earthquake significantly damaged the San Francisco–Oakland Bay Bridge and caused serious disaster. It also caused serious damage to other bridges that affected the rescue efforts. Meanwhile, many of the old bridges in the world were built more than 30 years ago and are required to be strengthened to resist earthquakes and to extend their service life. In this study, the Abaqus finite element program is employed to analyze the nonlinear behavior of bridge piers under soil and structure interaction. The concrete pier and concrete pile are modeled by the concrete damage plasticity model. The reinforcing steel is modeled by the elastic-perfectly plastic model. The soil is also modeled by an elastic-perfectly plastic model with the Mohr-Coulomb yield criterion. In addition, infinite elements for soil are used to simulate the infinite domain of earth. Finally, fiber reinforced plastics (FRP) are modeled with the nonlinear stress-strain relations suggested by Hahn and Tsai and with the Tsai-Wu failure criterion. For the numerical analyses, nonlinear finite element analysis of RC bridge piers strengthened by FRP under the soil-pile interaction are carried out. Parametric studies are performed to study the effect of laminate layup of FRP, strengthening area of FRP, mono pile, group piles and scour depth of piles on the ultimate strength and failure behavior of bridge pier system and important conclusions are given.