Three dimensional modeling of triple friction pendulum isolators

This paper presents techniques for modeling triple pendulum isolation bearings subjected to three-dimensional (3-D) excitation. The behavior of the triple pendulum bearing has been described in the XY plane. The XY plane includes the vertical degree freedom and one lateral degree of freedom. However, the bearing behavior is considerably more complex in three dimensions due to the interaction of the four sliding surfaces and their respective restraints. Although shake table tests have shown the bearings to have good performance under threecomponent earthquake excitations, it is important develop a robust analytical model capable of explicitly capturing the 3-D behavior of each internal component. A non-linear, kinematic model is used in the analysis of the bearing three-component motion. Experiments were conducted using the shake table at the University of California, Berkeley as part of an effort to characterize the 3-D behavior. A comparison between the experimental data and the corresponding results of the kinematic model shows favorable agreement.