Seismic Response Analysis of Double-Layer Isolation Structures in High-Rise Buildings

(1) Research background: The aim of this study was to investigate the response patterns of double-layer isolation structures under seismic actions. (2) Methods: A numerical model of an 18-story reinforced concrete frame, with a core tube double-layer isolation structure designed using YJK (3.0), was established. Three seismic waves were inputted into the model, and numerical simulations were carried out using the finite element calculation software ABAQUS (2022). Additionally, the seismic responses of different double-layer isolation models were analyzed. (3) Results: The double-layer isolated structure had a significantly prolonged natural vibration period, and the seismic effects were reduced by adding an upper isolation layer. This layer decreased the maximum displacement of the isolation layer and reduced the acceleration response of the superstructure by 16.1% to 53.3%, effectively controlling story shear forces and overturning moments. Compared with inter-story isolation systems, the shear force below the isolation layer can be 1.3~3 times higher in double-layer isolation structures, thereby mitigating threats to equipment and personnel safety. (4) Conclusions: The double-layer isolation structure demonstrated optimal seismic performance when the upper isolation layer was positioned within the bottom one-third of the structure.