Finite element study of the effect of support rotation on the horizontal behavior of elastomeric bearings

Laminated elastomeric bearings are used widely in both seismic and non-seismic structural engineering applications. The behavior of these bearings under pure loading (compression, shear, or bending) and under combined compression-shear loading has been studied at various levels in previous studies. However, very few studies have considered the behavior of elastomeric bearings under combined loading that includes rotation, and, to the best of the authors' knowledge, there has been no previous study on the effect of rotation on the lateral stability of elastomeric bearings. In bridge applications and some novel seismic isolation applications, e.g., isolation of high-rise buildings and mid-height isolation, it is possible for elastomeric bearings to experience rotation, the effect of which is not well understood. This paper studies the effect of rotation on the horizontal behavior of elastomeric bearings using 3D Finite Element Analysis (FEA). It is observed that constitutive modeling assumptions can have a notable influence on the results, especially at low vertical pressure where the critical shear strain is large. Support rotation does not affect the critical displacement appreciably, but it significantly affects the critical shear force. It is observed that support rotation becomes important for bearings with low second shape factor, even if their first shape factor is large.