Seismic performance analysis of a large-scale single-layer lattice dome with a hybrid three-directional seismic isolation system

A large number of studies and applications have been carried out on horizontal seismic isolation systems, and their effectiveness has been indicated. For long-span spatial structures, vertical seismic load plays an important role. However, vertical seismic isolation technology has not been extensively investigated. In this paper, a hybrid bearing with three-directional seismic isolation effects is proposed, in which the triple friction pendulum component and the viscous damping component are combined in series. Compared with other seismic isolation systems, the advantages of this hybrid seismic isolation system are that it can not only greatly lengthen the structural periods but also dissipate the seismic energy in all three directions. A hybrid numerical modeling method for this hybrid seismic isolation bearing is also developed. The seismic performance of a welded large-scale single-layer lattice dome with this hybrid seismic isolation system subjected to near-field ground motions is analyzed. The results show that the important dynamic demands in the dome are significantly suppressed compared with the base-fixed dome. The seismic isolation effects are evaluated in all three directions, and the effectiveness of the hybrid isolation system is verified. Finally, a comparative study is performed, and the mechanical parameters of this hybrid bearing are discussed. It is found that the damping energy dissipation in the seismic isolation bearings is not the most important factor in reducing structural dynamic demands. The proposed seismic isolation system and its numerical modeling method provide an attractive and effective alternative for the design of long-span spatial structures with hybrid seismic isolation systems.