Modeling of high damping rubber bearings under bidirectional shear loading

The behavior of high damping rubber bearings is highly complex. The models that are currently available are generally limited to unidirectional motion and, in most cases, difficult to extend to general bidirectional loading. One of the major limitations is their inability to characterize the behavior of the bearings at different levels of shear deformation. In the present work, a set of bidirectional models are presented, obtained by combining relatively simple bi-dimensional formulations. The models are calibrated over a set of unidirectional test data
and are shown to accurately describe the response of the bearings at low, intermediate and high strain levels using a single set of parameters. Validation is carried out using bidirectional displacement-controlled tests available in the literature and numerical simulations are performed of a base-isolated building subjected to free vibration and bidirectional earthquake excitation.