Mechanical Properties and Earthquake Response Analysis of Seismic Isolation Bearing with Displacement-Restraining Device

Abstract

Traditional lead rubber bearings (LRB) often fail under strong earthquakes due to excessive horizontal displacement of the isolation layer, which is caused by the lack of a synchronous displacement limiting mechanism. To address this issue, this study proposes a novel Displacement-Restrained seismic isolation Bearing (DRB) integrated with an "X"-shaped steel cable displacement-restraining device and conducts systematic studies: a three-stage mechanical model of the DRB was established, followed by pseudo-static comparative tests with conventional LRB under the same axial compression ratio; a refined finite element model (FEM) was developed using ABAQUS for verification; and both bearings were applied to a 4-story reinforced concrete frame (8-degree seismic intensity, 0.30g) for performance-based analyses under three seismic scenarios in accordance with GB/T 51408-2021. Test results show that the DRB significantly enhances horizontal displacement confinement after limiter activation, with FEM simulation errors <1%. Structural analyses indicate that the DRB maintains consistent performance with the LRB under Design-Basis Earthquake, activates its limiting function under maximum considered earthquake, and prevents structural collapse under very rare earthquake (inter-story drift <1/100), whereas excessive displacement of the isolation layer induced by the LRB leads to total structural collapse. This study’s DRB integrates seismic isolation and displacement limiting, providing an efficient, reliable, and engineerable solution for isolated structures in high-intensity earthquake zones and addressing the key failure issue of traditional LRBs.