Shaking Table Tests and Numerical Analysis of the Interaction of a Base-isolated Steel Frame's Responses with a Long-span Roof

Seismic isolation technology has been extensively used in long-span spatial structures to alleviate losses caused by earthquake disasters. However, limited experimental studies have been conducted to examine the impact of horizontal and vertical vibrations in long-span roof structures with rubber bearings as isolation layers on the isolation effect. This paper presents a study that carried out shaking table experiments on 1/40 scale long-span steel frames, both with and without base isolation. It explores the interplay of horizontal and vertical vibrations in long-span roof structures equipped with rubber bearings, and its influence on the isolation effect. Three ground motions, including horizontal bidirectional (2D) and bidirectional-plus-vertical (3D) components were used as the seismic excitations. The whole structural dynamic responses of the base-isolation (BI) model and fixed-base (FB) model, the local responses of the grids and isolation bearings were measured. Under 2D seismic excitation, the grid layer in the FB model exhibits a substantial vertical acceleration response. When exposed to 3D seismic activity, the isolation system successfully delivers its expected isolation outcome. Although the isolation bearings could not attenuate the vertical seismic acceleration response induced by vertical ground motion, they effectively reduced the vertical dynamic response generated by the coupling by suppressing the horizontal seismic response.