Although the behavior of friction sliding bearings is well understood, the failure behavior has not been thoroughly investigated. However, predicting and understanding the failure of bearings is an important key in designing isolated structures to minimize their collapse in extreme events, and thus, this study is critical. Because of its relative simplicity and particular availability in certain markets, the failure of the double friction pendulum (DFP) bearing at its physical displacement limit is investigated. The bearing is modeled with a rigid body model including inertia for each of the bearing components. A nonlinear viscoelastic impact model is included to simulate the impact between bearing components. As isolation systems are particularly vulnerable to long-period excitations, analytical pulses are used as input excitations to investigate the influences of pulse parameters on the failure of DFP. The influences of DFP design parameters are investigated as well. To confirm that the response to the analytical pulses correctly represents the behavior under long-period ground motions, wavelet analysis to is performed on 14 pairs of pulse-type ground motion records to extract their pulses, and the failure prediction made from the extracted analytical pulse is compared with the failure from the real ground motions. It is found that using the extracted pulses provides a good estimation for the failure prediction of the ground motions.

Summary A freestanding rigid block subjected to base excitation can exhibit complicated motion described by five response modes: rest, pure rocking, pure sliding, combined sliding‐rocking, and free flight. Previous studies on the dynamics of a rocking block have assumed that the block does not interact with neighboring objects. However, there are many applications in which the block may start or come in contact with an adjacent boundary during its motion, for example, a bookcase or cabinet colliding with a partition wall in an earthquake. This paper investigates the dynamics of a sliding‐rocking block considering impact with an adjacent wall. A model is developed in which the base and wall are assumed rigid, and impact is treated using the classical impulse and momentum principle. The model is verified by comparing its predictions in numerical simulations against those of an existing general‐purpose rigid‐body model in which impact is treated using a viscoelastic impact model. The developed model is used to investigate the effects of different parameters on the stability of a block subjected to analytical pulse excitations. It is found that wall placement (left or right) has a dominant effect on the shape of the overturning acceleration spectra for pulse excitations. In general, decreasing the gap distance, base friction coefficient, and wall coefficient of restitution enhance the stability of the block. Similar observations are made when evaluating the overturning probability of a block using earthquake floor motions.

Summary While isolation can provide significantly enhanced performance compared to fixed‐base counter parts in design level or even maximum considered level earthquakes, there is still uncertainty over the performance of isolation systems in extreme events. Researchers have looked at component level stability of rubber bearings and on the effect of moat impact on behavior of structures isolated on general bilinear isolators. However, testing of triple friction pendulum (TFP) sliding bearings has not been done dynamically or incorporated into a building system. Here, one‐third scale laboratory tests were conducted to on a 2‐story 2‐bay TFP‐isolated structure. Input motions were increasingly scaled until failure occurred at the isolation level. As the superstructure was designed with a yield force equivalent to the force of the bearing just at their ultimate displacement capacity, there was minimal yielding. A numerical model is presented to simulate the isolated building up to and including bearing failure. Forces transferred to the superstructure in extreme motions are examined using both experimental and numerical data. Additionally, the effect of the hardening stage of the TFP bearing is evaluated using the numerical model, finding slight benefits.

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