Distinct element modeling of the dynamic response of a rocking podium tested on a shake table

A blind prediction contest was organized to evaluate the ability of different modeling approaches to simulate the seismic rocking response of a full-scale four-column podium structure. The structure was tested on a shake table, and was subjected to two bidirectional ground motion ensembles comprising 100 synthetic records each. This short communication presents the main assumptions and results from the model, developed using the distinct element method, which provided the second-best prediction of the experimental results. A comparison of the model predictions and the experimental results demonstrates that the numerical model was generally able to reproduce the large displacements induced by the more intense ground motion ensemble, while tending to overestimate the displacements of the less intense earthquake ensemble. This overestimation of the response was reduced through the inclusion of damping in the system. However, the addition of damping greatly increased the solve time, which is problematic for a competition, and in the case of the more intense ground motion ensemble also resulted in an underprediction of the maximum response of the structure.

Automated summary

The study evaluated the ability of different modeling approaches to simulate the seismic rocking response of a full-scale four-column podium structure through a blind prediction contest. Experiment results showed that the numerical model was generally able to reproduce the large displacements induced by different ground motion ensembles, but tended to overestimate the displacements of the less intense earthquake ensemble. The inclusion of damping helped reduce this overestimation of the response, but also increased solve time and led to an underprediction of the maximum response in the more intense ground motion ensemble.