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Floor isolation systems (FISs) are used to mitigate earthquake-induced damage to sensitive building contents and equipment. Traditionally, the isolated floor and the primary building structure (PS) are analyzed independently, assuming the PS response is uncoupled from the FIS response. Dynamic coupling may be non-negligible when nonlinearities are present under large deflections at strong disturbance levels. This study investigates a multi-functional FIS that functions primarily as an isolator (i.e., attenuating total acceleration sustained by the isolated equipment) at low-to-moderate disturbance levels, and then passively adapt under strong disturbances to function as a nonlinear (vibro-impact) dynamic vibration absorbers to protect the PS (i.e., reducing inter-story drifts). The FIS, therefore, functions as a dual-model vibration isolator/absorber system, with displacement dependent response adaptation. A scale experimental model—consisting of a three-story frame and an isolated mass—is used to demonstrate and evaluate the design methodology via shake table tests. The properties of the 3D-printed rolling pendulum (RP) bearing, the seismic gap, and the impact mechanism are optimized to achieve the desired dual-mode performance. A suite of four ground motions with varying spectral qualities are used, and their amplitudes are scaled to represent various hazards—from service level earthquake (SLE), to design basis earthquake (DBE), and even maximum considered earthquake (MCE). The performance of the multi-functional FIS is established and is described in this paper.
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