Performance of Seismically Isolated Pile-supported Structures through 1 g Shaking Table Tests

This study fabricated friction pendulum (FP) and rolling pendulum (RP) seismic isolation systems using 3D printing to conduct 1g shaking table tests of pile-supported structure models incorporating these systems. The test results indicate that, when the FP bearing was applied to the pile heads, the acceleration response of the structure decreased once the FP bearing began to operate; as the input earthquake frequency increased (1, 3, and 10 Hz), the seismic isolation system engaged at lower input accelerations (0.16, 0.11, and 0.02 g, respectively), and the deck acceleration response decreased significantly (15, 37, and 65%, respectively) compared to that in the fixed pile head condition. Similarly, when the RP bearing was applied to the pile heads, a higher input earthquake frequency (1, 3, and 10 Hz) corresponded to a greater decrease in the deck acceleration response (82, 95, and 96%, respectively) compared to that in the fixed condition. However, a significant deck displacement was observed when using the RP bearing owing to the resonance phenomenon when the natural period of the structure was similar to the frequency of the input earthquake. Therefore, since applying RP bearing is not desirable in terms of structural displacement, it is appropriate to apply FP bearing, which can avoid resonance by changing the natural period during the operation of the seismic isolation system.