Latest revision as of 14:43, 30 November 2021

Abstract

The Forbidden City, the former Chinese imperial palace, now houses the Palace Museum. It is not only famous for its splendid wooden palace complex, but also prestigious for the millions of precious artefacts stored. The Forbidden City is located in the center of Beijing, which is a high seismic hazard zone. Wooden structures usually perform well during earthquakes because of their large deformation and damping capacities. Meanwhile, most artefacts are fragile due to their delicate shapes and aging issues, and also due to their unanchored place form. Only a few of those artefacts are on exhibit, while most of the others are placed in cabinets and stored in warehouses. This paper focuses on seismic protection of these cabinet stored artefacts. Considering the tremendous amount and the rigorous requirements for moving the artefacts, base isolation is not a favored method. Using base isolation requires lifting the artefacts or cabinets while installing isolation bearings and this is very time consuming because of the rigorous requirements for moving artefacts. Also, artefact damage might happen during this process. Thirdly, much more spaces are required to accommodate the potential isolation deformation. Considering all these adverse aspects, this paper tries to use dampers to connect all adjacent cabinets to enhance the integrity and increase the damping ratio and thus protect the stored artefacts. This method is applicable for both new and existing cabinets. No artefact movement and extra space are required. All the dampers are installed with mechanical buckles and the whole installation is reversible. In order to validate the effectiveness of this method, shake table tests and finite element analyses based on practical cabinet layout with and without this damping method are designed and conducted. Ten ground motions are chosen and used to conduct fragility analyses. The cabinet sliding displacements are chosen as the damage index. Seismic fragility curves of the cabinets with and without dampers are plotted and compared. Results demonstrate the effectiveness of the proposed damping method.

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