A vertical isolation device with variable stiffness for long-span spatial structures

A vertical isolation device with variable stiffness (VIVS) is developed using multiple hydraulic cylinders, which can form a three dimensional (3D) isolation device with a horizontal rubber bearing. The components and control mechanism of the VIVS are explained in detail. A prototype of the VIVS is fabricated to verify its performance by sinusoidal motion tests and shaking table tests. The experimental results show that the variable stiffness characteristics of the VIVS can be achieved, and the isolation period reaches 1.2 s. The shaking table test also verifies the effectiveness of the VIVS in controlling the acceleration. A theoretical model for the VIVS is proposed and validated, and a 60 m single-layer reticulated dome is simulated based on the model. The results indicate that the axial force and acceleration of the structures with VIVS are effectively mitigated with reduced height and displacement of the VIVS. •A vertical isolation with variable stiffness is developed using hydraulic cylinders.•Various tests are conducted to investigate the performance of the isolation.•A theoretical model of the isolation is proposed and validated.•Numerical analysis is conducted for a single-layer reticulated dome.•The isolation mitigates the responses with reduced height and displacement.