This paper reports on the evaluation of the response of unanchored building contents in two separate shaking experiments, with the goal of developing simplified seismic fragility functions to be used for content disruption. The content response was evaluated collectively, by defining qualitative categorical ratings of overall content disruption based on observation of specific behaviors, such as sliding, toppling, rolling, or falling. Next, these disruption ratings were correlated to demand parameters, such as peak floor acceleration and peak floor velocity. Fragility functions were developed by combining two alternative implementations of the bounding demand data method. Among the demand parameters evaluated, peak floor velocity is shown to be a consistent indicator of disruption when comparing results from the two independent data sets. Vertical acceleration is shown to also influence the demand intensities that trigger disruption.

Summary This paper focuses on slab vibration and a horizontal‐vertical coupling effect observed in a full‐scale 5‐story moment frame test bed building in 2 configurations: isolated with a hybrid combination of lead‐rubber bearings and cross‐linear (rolling) bearings, and fixed at the base. Median peak slab vibrations were amplified—relative to the peak vertical shake table accelerations—by factors ranging from 2 at the second floor to 7 at the roof, and horizontal floor accelerations were significantly amplified during 3D (combined horizontal and vertical) motions compared with 2D (horizontal only) motions of comparable input intensity. The experimentally observed slab accelerations and the horizontal‐vertical coupling effect were simulated through a 3D model of the specimen using standard software and modeling assumptions. The floor system was modeled with frame elements for beams/girders and shell elements for floor slabs; the insertion point method with end joint offsets was used to represent the floor system composite behavior, and floor mass was finely distributed through element discretization. The coupling behavior was partially attributed to the asymmetry of the building that was intensified by asymmetrically configured supplemental mass at the roof. Horizontal‐vertical coupled modes were identified through modal analysis and verified with evaluation of floor spectral peaks.

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