Study on the pier bottom self-centering seismic isolation structure of the high-pier continuous rigid frame bridges

Four seismic isolation specimens were designed, fabricated, and subjected to physical loading tests to enhance the seismic performance of a high-pier continuous rigid-frame bridge. A finite element model of the seismic isolation structure of the high-pier was established using numerical simulation software. The entire bridge model was established based on the multi-scale modeling method to investigate the seismic response of the high-pier continuous rigid frame bridge under different seismic waves. The results indicate that the seismic isolation pier has self-centering and energy dissipation capabilities. The seismic isolation pier has satisfactory energy dissipation capacity and ductility when the ratio of the long-axis and short-axis radii is 1.5. The results of the finite-element simulation corresponded well with the experimental results. Significant damage occurred to the concrete at the bottom and corner of the pier, and the reinforcement did not reach its yield strength throughout the loading process. Therefore, measures must be implemented to ensure the seismic performance of the structure. The pier bottom self-centering seismic isolation structure effectively absorbs shocks, as evidenced by reduced absolute acceleration and relative displacement at the pier top, decreased shear force and bending moment at the pier bottom, and minimized girder displacement. It was recommended that the ratio of the long-axis and short-axis radii be adopted as 1.5-2.0 and that the pier height be selected as 60 m-100 m. These results provide a reference for the research and applications of this type of structure.