Finite element analysis of the seismic shake‐table response of a rocking podium structure

Abstract

AbstractRocking podium structures consist of rocking columns supporting a platform to achieve kinematic seismic isolation of the superstructure above. This article presents detailed finite element (FE) analysis modeling and results of the benchmark rocking podium structure that was tested as part of a blind prediction contest organized by the Pacific Earthquake Engineering Research center (PEER) at UC Berkeley, the University of Bristol, and ETH Zurich in 2019. Details of the FE modeling approach, as well as a discussion on key results and findings of this study are outlined herein. It was found that the FE model of the rocking podium structure was not sensitive to the element type, mesh layout or maximum time step, while the choice of contact algorithm influences the stability of the predicted rocking behavior. Modeling of the friction interactions between the rocking interfaces also had a nontrivial influence on the dynamic rocking response as it represented the main source of energy dissipation in the system. Further, instead of assuming an arbitrary value for inherent damping which was deemed to be very low for such a structure, explicit modeling of the frictional dissipation mechanism at the column‐to‐podium interface was preferred in this study.