Shaking table tests of sliding‐prone blocks subjected to unidirectional and bidirectional ground and floor motions

Freestanding museum collections with low friction coefficients and high aspect ratios may be damaged due to excessive sliding displacements during earthquakes. However, several key issues have not been adequately addressed, such as the friction and sliding behavior of museum collections under actual conditions. Unidirectional and bidirectional shaking table tests were conducted to determine the maximum sliding displacements (MSDs) of a freestanding glass block on sandpaper, which had the lowest friction coefficient among forty‐two contact interfaces in slow‐pull tests. Fourteen far‐field and fourteen near‐fault pulse‐like ground motion records were applied with peak ground accelerations (PGAs) of the major components scaled from 0.05 to 0.6 g. Shaking table tests of a full‐scale three‐story reinforced concrete frame structure containing glass blocks were carried out. Seismic fragility curves corresponding to the sliding failure of the glass block were generated based on the experimental results considering the friction coefficient uncertainty. The results show that the influence of the bidirectional interaction on the MSD is more significant for near‐fault pulse‐like ground motions than far‐field ground motions. For a specific ground motion record, the sliding displacement of the glass block may not increase with the increase of the PGA or peak floor acceleration due to the friction coefficient uncertainty, but this has a negligible influence on the fragility. A clearance around sliding‐prone museum collections with friction coefficients larger than 0.20 is recommended to ensure that the probability of exceedance is lower than 5%.