A comparative study on the effectiveness of bidirectional and tridirectional isolation systems used in large-scale single-layer lattice domes during earthquakes

To improve the structural seismic performance, structural vibration control technology is widely introduced into building structures. In terms of base isolation, both bidirectional and tridirectional isolation systems are usually used in large-scale domes. However, the difference in the isolation performance between the two systems needs to be evaluated and further understood. In this paper, large-scale single-layer lattice domes with bidirectional and tridirectional isolation systems are investigated and compared under near-field and far-field ground motions. The dynamic demands of isolated structures are quantified, and the isolation effectiveness of different isolation systems is evaluated. The effects of the near-field and far-field ground motions on isolated structures are compared. The seismic performance of isolated structures is analyzed based on incremental dynamic analysis (IDA). In addition, a parametric study is performed to discuss the effect of the damping coefficient of the damper in the tridirectional isolation system on the isolation effectiveness. It is found that from a statistical point of view, both the bidirectional and tridirectional isolation systems are able to reduce the dynamic demands of domes during earthquakes, while the tridirectional isolation system has better suppression effectiveness for dynamic demands; the near-field earthquake ground motions have a more obvious influence on isolated structures than the far-field earthquake ground motions. For the tridirectional isolation system, a larger damping coefficient may not necessarily be able to obtain better isolation effectiveness in structures. This study provides a basis for improving the understanding of the isolation effectiveness of different isolation systems used in large-scale domes.