Enhancing the overturning resistance capacity of high aspect ratio structure through hybrid base isolation and inter-storey isolation

The high-aspect ratio of structures is usually limited to a small range for base isolation (BI), due to the necessity of ensuring resistance to overturning. This limitation restricts the application of friction pendulum bearings (FPBs) in structures with large high-aspect ratios. This article aims to explore the application of hybrid base isolation and inter-storey isolation (BIISI) in structures with large high-aspect ratio. The theoretical basis of the BIISI was first analyzed in terms of overturning resistance. Subsequently, nonlinear dynamic numerical simulations were conducted on a building with a high aspect ratio to simulate its response subjected to typical pulsetype and non-pulse-type earthquakes. The overturning resistance of the structure and seismic dynamic responses were evaluated. A series of parametric studies were also conducted to investigate the effects of FPB properties, peak ground acceleration (PGA), the friction coefficient ratio and the radius of FPBs between inter-storey isolation storey and base isolation storey on the overturning resistance performance of isolated structures. It is demonstrated that superstructure is meticulously partitioned into two independent sliding structural elements through the BIISI, and it can significantly improve the overturning resistance of buildings with a large highaspect ratio. PGA and FPB properties show significant differences, but the friction coefficient ratio and the radius of FPBs between the inter-storey isolation storey and base isolation storey show limited influences on the overturning resistance of the structure.