Seismic Isolation Research on a Double-Layer lattice Structure Using Shaking Table Tests

Typical failure patterns of members, supports, and joints were observed in double-layer lattice space structures during the 2013 M7.0 Lushan earthquake in the Sichuan province of China. Various isolation supports have been implemented in recent years to enhance the structural performance by reducing the dynamic responses. However, these isolation supports mostly focus on either horizontal isolation or vertical isolation, which is not applicable for synchronous isolation in both horizontal and vertical directions. Therefore, an innovative isolated support used for three-dimensional isolation was invented. In order to verify the feasibility of using the isolated support to reduce the earthquake response of double-layer lattice structures under small to strong earthquakes, a scale model was subjected to a shaking-table test before and after application of the isolated support. The dynamic characteristics, earthquake performance and failure pattern of the model with and without the isolated supports are discussed based on the earthquake responses, including acceleration, displacement, and strain. Results of the test indicate that the earthquake effect is underestimated without regard to the dynamic amplification effect of the lower supporting reinforced concrete structures, which led to the failure of the structure. The compared experimental results indicate that the isolated supports had remarkable earthquake isolation and reduction in both the horizontal and vertical directions.