Experimental and numerical investigations on seismic responses of base-isolated reticulated shells under near-fault earthquake ground motions

Base-isolated large-span spatial lattice structures are widely used in high-seismicity regions to mitigate seismic risk. However, near-fault ground motions, particularly those characterized by large-amplitude, long-period velocity pulses, may induce substantial seismic demands on these structures. To systematically investigate the effects of velocity pulses, a representative base-isolated single-layer cylindrical reticulated shell was studied through shaking table tests and finite element simulations under paired pulse-like and non-pulse ground motions. Nodal accelerations and displacements, as well as member strains, were systematically compared. The results demonstrate that velocity pulse components can significantly amplify structural accelerations, displacements, and strains, with the strongest amplification occurring when the pulse period approaches the fundamental period of the structure. Based on the combined experimental and numerical results, near-field amplification factors of 1.5 for nodal responses and 1.8 for member responses are recommended for considering velocity pulse effects in the seismic design of large-span spatial lattice structures in high-seismicity regions.